Flight Computers

Gagarin

WiFi controlled, 6 output, 2 input channel flight computer

Compatible with Shepard tracker

From £115

Buy now

Grissom

WiFi controlled, 2 output channel flight computer

Compatible with Shepard tracker

From £65

Buy now

Trackers

Shepard

WiFi controlled, GNSS + LoRa tracker

Requires a Goddard ground station
Compatible with Gagarin and Grissom

From £75

Buy now

Goddard

WiFi controlled, LoRa receiver and ground station

Requires a Shepard tracker
Compatible with Gagarin and Grissom

From £75

Buy now

Titov

433MHz direction finder

Tiny form factor, frequency and beep pattern programmable

From £45

Buy now

Purchase facility coming soon. Meanwhile, contact trullock@gmail.com

Gagarin is a WiFi controlled flight computer with an advanced but simple to use interface.

It provides ample features for the most advanced use-cases, whilst supporting simple setup and use through a clean and modern web-based interface.

Configure, arm, disarm and view flight log all online without any custom apps, hardware or cables.

Connect via your phone's WiFi hotspot to benefit from additional features such as free cloud backup of configurations and flight logs and geolocation - no more connecting to each flight device separately!

The extremely detailed flight log viewer shows the most detailed breakdown of flight events of any computer on the market, making debug and diagnostics very easy.

• IMPORTANT: Gagarin users MUST NOT update to version 1.2.241. Go straight to 1.3.x or above.
• Descent Velocity triggers currently occur after just one speed sample exceeds the set threshold. If you have a particularly noisy descent, either due to vent-hole effects or other buffeting, you may get speed spikes which exceed this threshold but do not reliably indicate a fast, sustained descent. We recommend either not using this mode until a future firmware update is released which add additional smoothing/sampling, or use a high threshold value.
• Some captive browsers (the browser you get when connecting to Gagarin by clicking Sign In To WiFi) do not handle file downloads very well. If you are connected in this way and are struggling to download flight logs, try connecting directly using your normal browser. See the Quickstart guide for connectivity advice.

If you dont need this many outputs or input channels check out Grissom.

Dimensions can be found on the specifications page.

Warranty

The devices are provided "as-is" and we make no warranties, whether express, implied, or statutory, regarding or relating to the products or any materials or services furnished or provided. To the fullest extent allowed by law, we specifically disclaim all implied warranties of title, merchantability, non-infringement, and fitness for a particular purpose (even if we has been informed of such purpose).

The devices we provide are part-assembled and therefore we have not performed any testing to ensure their function in accordance with any expectations or ensured they are fit for any particular purpose. It is the end user's responsibility to ensure the final, assembled device along with any firmware installed functions as they would expect and the end user assumes all liability for the use of the device and any outcomes from using the device.

The firmware provided is for demonstration purposes only and we make no warranties, whether express, implied, or statutory and we specifically disclaim all implied warranties of title, merchantability, non-infringement, and fitness for a particular purpose.

Compliance statement

The Gagarin hardware is an educational device intended to help you learn how to build similar devices. The devices come part assembled for any reseller or end user to finalise. The devices come with no system on chip attached however one is provided with example firmware for demonstration purposes only.

Not a product

CE/UKCA: What we sell is very specifically a "part-assembled PCB", a "component", and not itself a "finished product". It has no case, leads, or power supply. Whilst the example system on chip provided has a CE mark in itself, we don't make any CE/UKCA conformance statement for this as a product as it is not a product. If someone resells/installs these devices in a form closer to the definition of a product then they need to ensure compliance with legislation.

Other regulations: It is unclear if the UK law: The Product Security and Telecommunications Infrastructure Act 2022, and The Product Security and Telecommunications Infrastructure (Security Requirements for Relevant Connectable Products) Regulations 2023 apply here or not. As we say, it is not a "finished product". However, just in case it does apply, this statement is an attempt to meet the requirements.

As the Gagarin hardware can be assembled and distributed by anyone, obviously, if they make it, they have to consider compliance, so this statement only applies to cases where we have made the Gagarin hardware, which we do not do anyway.

The product (if somehow it is deemed a product)

As the Gagarin hardware is a general purpose module / circuit, it only really makes sense to make any statement about it "as supplied", which is with the demonstration Gagarin software pre-loaded for your convenience.

If you choose to load any other software, or even build a variation of the Gagarin software with your own (or someone else's) changes, then it is no longer "as supplied", and you now have a different "product" (if it is a "product") that you have made, so compliance is then up to you.

Type/batch

So, the "product" (which it isn't) is the software provided on the demonstration system on chip, all batches and builds, on the Gagarin hardware made and supplied by Ivelop Consulting Ltd, and "as supplied", or as updated from the OTA server.

Who

The software is made by Andrew Bullock, and other open source contributors. However, I can only speak for me (Andrew Bullock), I have no idea if any and all OS library contributors also need to make a compliance statement.

When Ivelop Consulting Ltd manufactures and distributes boards, its name is "Ivelop Consulting Ltd", UK company 14434046, and its registered office address is 4 Cross Street, Beeston, Nottingham, Nottinghamshire, United Kingdom, NG9 2NX.

Statement made by manufacturer

The hardware covered here is made by/for Ivelop Consulting Ltd. This statement is prepared by Andrew Bullock, director Ivelop Consulting Ltd, on behalf of the "manufacturer".

Compliance

It is the opinion of the manufacturer that we have complied with Schedule 1 & 2, and 5.1-1 of ETSI EN 303 645. Specifically that where passwords are used, they are user specified, and that we have a vulnerability disclosure policy, etc.

• Normal web access to controls for your device have no passwords.
• Access to settings can have no password, or can have a user specified password.

Vulnerability disclosure policy

Please raise any security issue by contacting us. I would expect to reply promptly but at the very least within one month, and will reply to provide any status updates. As the demonstration software provided is free with no contract or warranty, saying I'll reply in a month is not a contractual statement. In practice I usually reply within hours.

Please note that not all issues are security issues, and this policy applies only to "security issues".

Support / updates

Updates are made via an OTA server.

Support period

I plan to continue to support this product until I get bored, or drop dead, whichever is sooner. I expect that to be many more years.

Issued

2024-09-19

Processor

First, you should attach the processor. Position it so that all the castellations neatly line up with the receiving pads. Hold the processor in place with some tape. Using a fine tipped soldering iron and fine flux-cored solder, work your way around the castellations, flowing solder into the joint.

The Red pins are attached to the ground plane and will require much more heat from your iron to get them up to soldering temperature, we recommend you do these pins last.

We recommend starting with the Blue pin, followed by the Yellow pin. If you do not alternate the sides initially, soldering all along one side can cause the processor to lift up, creating a gap on the opposite side.

Use a mignifying eyepiece to fully inspect each solder joint and ensure all are properly and cleanly connected with no bridged pins.

It is not necessary to solder the ground pad (Green) underneath the processor, but a small blob of thermal conductive paste won't hurt.

Processor positioning

System test

Before you attach the next components you should power up the board and navigate to the system-test page (under Menu -> Device info -> System test) and ensure you are getting a reading from the altimeter. If it is reading 0m constantly then there is a problem with your board. Check the soldering joints on the processor. If the problem remains please contact your vendor for assistance.

Rectifier

The orientation for the rectifier should be obvious. Ensure you properly solder the tab and both legs properly.

Rectifier positioning

Through-hole components

Attach the buzzer (blue cricle), getting the correct orientation (note the + marked on the board and component).

Attach the FET (red rectangle). Note that the metal tab on the back of the component faces east (to the right on the picture), towards the centre of the board.

Attach the output and input/touch connector blocks (green rectangles), ensure they are properly seated and the right way around before soldering all pins.

Through-hole component positioning

System test

Power up the board and navigate to the system-test page (under menu -> Device info -> System test) and ensure you are still getting a reading from the altimeter. If it is reading 0m constantly then there is a problem with your board. Check the soldering joints on the processor. If the problem remains please contact your vendor for assistance.

Perform a system-test with indicator loads (we recommend mini 9V filament bulbs) on the output channels and ensure they all fire properly.

If you purchased your Gagarin as a kit you will first need to assemble it.

Next you need to decide how you're going to power your Gagarin. Fully read the Power documentation to avoid damaging your device.

When you power your Gagarin up, it will make 3 beeps if booting into ultra-low-power mode, and 6 beeps when it boots up fully either directly or by being woken from ultra-low-power mode. If it makes 2 beeps, looping indefinitely then there is a hardware issue and you should contact your vendor. Do not fly your device in this state.

Once your Gagarin is assembled and powered up, it will create a WiFi Access Point which you can connect to with any compatible device.

The WiFi SSID will be of the form "Gagarin AABBCC", where AABBCC is a unique ID for device. The default password is blank, you should change this straight away once connected.

Use the WiFi settings on your phone/laptop to connect to your Gagarin's Access Point. After you connect, your phone/laptop will tell you to "Sign In" to the WiFi network. This is a feature of WiFi networks that allows a webpage to be opened immediately after connecting. Usually this is used by public WiFi networks to authenticate you. Here it's used as a convenience so you don't need to remember or type in an IP addresses to get started. If this message doesn't pop up automatically, there should be a Sign In button in your device's WiFi settings page to click.

If your device says something to the effect of "This network does not provide Internet connectivity, do you want to stay connected?" Choose Yes, otherwise you will be disconnected and have to start again.

Some devices' default behaviour is to automatically disconnect you from WiFi networks that do not provide Internet connectivity. If you are struggling with this, disable your mobile Internet.

The first thing you will see on the device's Flight Control page is a warning about insecure WiFi.

Click the Configure Connectivity button to fix this.

Provide a memorable password for the device's Access Point to secure it against unwanted users. If you forget this and can't otherwise connect to your device you'll need to do a Factory Reset.

We strongly advise using your Gagarin in Station mode. This means having it connect to another WiFi network such as one hosted by your phone's hotspot. This gives your device the ability to talk to the Internet and as such you get additional features: cloud backup of Flight Configurations and Flight Logs, Firmware updates and Geolocation.

The access point must be 2.4GHz, if using your phone's hotspot you may need to enable "Enhanced compatability mode" or similarly named feature to activate 2.4GHz mode.

The changes you make to your WiFi settings will not take effect until you have disconnected from Gagarin.

When you come to use Gagarin again you will either need to connect to the device's Access Point using the password you just created, or connect to it via the external WiFi network whos details you provided. To do this:

1. If your connected device supports mDNS (most do, but it can be flakey) you can visit http://gagarin_aabbcc.local (where aabbccdd are the same as the device's Default Access Point SSID)
2. If (2) doesn't work or mDNS is not available, you need to connect to your device by it's IP Address. To find this, you have 3 options:
   • Connect to your Gagarin's Access Point and goto the Device Info page under the main menu. Here it will tell you the device's Station IP (it can be connected to an access point and BE an access point at the same time). Make a note of this, disconnect from the Gagarin's Access Point and reconnect to the same network as the Gagarin and then visit that IP Address in your browser.
   • Consult your WiFi's router DHCP table to find the IP it gave your Gagarin
   • Connect a UART adaptor to the Gnd, Rx, Tx pins and observe the Serial output on boot, it will report it's Station IP.

If you are connected to your Gagarin in Station Mode, you may see an "Update available" hint. We recommend connecting this way at least initially and then periodically over time in order to check for updates which are published regularly.

If you see this, follow the onscreen instructions to update your device to the latest firmware to benefit from bug fixes and new features. You should not fly on out-of-date firmware.

See the Flight configurations page on exactly how to create a Flight Configuration.

Once you have activated a Flight Configuration, you're ready to do a bench test.

With a Flight Configuration activated, arm your device by clicking the Unlock slider and within 3 seconds press the Arm button.

Place one end of a drinking straw over the barometer on the board creating a reasonable seal. Suck the other end of the straw for as long as you can, first quickly increasing the suction and then gently releasing it, simulating the pressure change curve of a real flight.

5 seconds after the pressure has stabilised back to room conditions the device will automatically disarm and the Flight Control page will update accordingly.

You can then navigate to the Flight Log for the flight and correlate what it says the "flight" looked like and what events occured with what really happened to the output channels on your bench.

Hopefully everything happened as expected. Use this methodology to become familiar with Flight Configurations and their Rules before your first real flight.

12V is the absolute maximum voltage you should apply to the Battery terminals and 24V is the maximum you should apply to the Deployment Battery terminals.

5V is the minimum you should provide to the Battery terminals.

We recommend using at least a 400mAh 2S LiPo, which should last around 3 hours. If you need to use a smaller capacity LiPo we recommend enabling ultra-low-power boot mode to save battery.

7.4V (2S LiPo) is the minimum recommended voltage for the Deployment Battery. You can use less, but the continuity tests will not function correctly unless you have at least 6.7V for a zero resistance load (ignitor).

If you are testing on a bench power supply, we recommend using no more than 7V.

You need to consider the power dissipation of the onboard voltage regulator, the higher voltage battery you use the more power (heat) the regulator will have to dissipate. Ensure you mount your Gagarin so there is room for air to circulate under the board.

We do not recommend 9V PPP batteries as they cannot supply enough current to the ignitors and avoid CPU brownout.

If you want to use a single battery for both the logic and deployment, solder-bridge the "D. BATT Jumper" on the top of the board. We do not recommend putting two wires into a single screw-terminal connector as it can fail to grip properly, resulting in power loss mid-flight.

You should not power-up the Deployment Battery before the Battery, otherwise continuity tests and activation of the output channels may not function correctly.

With WiFi running and active connected clients (e.g. your smartphone whilst setting up your device) current consumption is approx. 140mA.

Typically flight electronics are enabled at the pad with a physical switch. Gagarin gives you the option to eliminate this point of failure by allowing you to boot the device into ultra-low-power mode, and then awaken it at the pad using a capacitive touch input. When in ultra-low-power mode current consumption is approx. 7mA. See Flight Configurations for more info.

You can additionally reduce power consumption by enabling low-power mode when Armed. In this mode, about 77mA is consumed. See Flight Configurations for more info.

The Dashboard of your Gagarin will show you the voltages of the Deployment Battery and Battery.

You can improve the accuracy of the voltage measurements by providing exact resistances for 4 resistors.

Measure the resistances of R6, R7, R8 and R9 and record their exact resistences with the board unpowered.

Hardware version 1.1.x

Once your board is assembled and up and running, navigate to the Settings page and input the measured values. This will provide improved voltage reporting. Be accurate, even a small resistance deviation can produce meaningful measurement differences.

The PCB is 28.6mm x 83.4mm and 1.6mm thick.

The mounting holes are 3mm diameter at 75.75mm x 20.75mm centres.

Fully populated, the device weighs approx. 20g.

The brain of Gagarin is an ESP32, dual-core, 240MHz, 32bit Xtensa LX6 microprocessor. It is designed to achieve the best power and RF performance, showing robustness, versatility and reliability in a wide variety of applications and power scenarios. It communicates via WiFi 802.11b/g/n in the unlicensed 2.4GHz. To comply with radio licensing laws you must build Gagarin exactly as specified and not modify the radio module in any way.

The input channels are optically isolated (ACPL-227) from the microprocessor, providing excellent electrical protection.

The output channels are individually driven by dedicated high-side grounded-load drivers (VN5E160STR-E). These have an internal current limiting feature of 10A, which is more than enough to power a hot-wire cutter for several seconds. Additional protection is provided by a MOSFET (NTD3055L104-1G) which isolates the negative connections of all the outputs until the device is armed.

Settings, Flight logs and Flight configurations are stored in the onboard NAND flash chip. This has an expected block-write-lifetime of 10,000 cycles which does put a finite lifespan on the device. The file system employs a wear-leveling algorithm to reduce flash wear and so this is unlikely to be a practical problem. If you had one flight a day, every day, we wouldn't expect this to be a problem within 3000 years.

The ground test page allows you to directly control the output channels of your Gagarin. This is useful for ensuring all your outputs are working properly and for testing ejection charges.

You can test:

• Output: Turn on then off
• Output: PWM
• Beeper: Beep n times
• LEDs

The continuity status of a selected output will be tested and shown. The continuity will either pass or fail. If the Deployment Battery voltage is insufficient, testing cannot happen.

Once you are ready to test, click the Unlock slider and press Conduct Test within 3 seconds. If you wait longer you'll need to unlock it again. This prevents accidental testing.

This is the main page of your Gagarin and is where you arm it for flight.

In order to fly you'll need/want to:

Click the Manage button under the Flight Configurations box to create a new or activate an existing Flight Configuration.

Your Gagarin will boot up with the previously activated Flight Configuration re-activated and ready to go.

The flight computer and deployment battery voltages are shown. They will be highlighted red if they are of a value that is low for a LiPo battery.

You will not be able to fly if you don't have enough free log space. Go to Flight Logs and delete some old logs if this is affecting you (See Flight Logs section for more information).

If your active Flight Configuration relies on any inputs, they will be shown with their current state to review and ensure they are as expected.

Your Gagarin will warn if you you have Rule Triggers or Rule Conditions which rely on a changing input state, where the input is already in the final state. This may or may not be a problem depending on your rocket's configuration. Only you will know what state inputs are supposed to be in pre-arming. Double check everything is as you expect.

If your active Flight Configuration turns output channels on or off, their continuity status will be shown for you to review and ensure they are as expected.

Your Gagarin will warn you if used output channels do not have continuity. This may be a false alarm for high-resistance hot-wire-cutters or other electronic components. Do bench tests and understand what your expected continuity results are.

You can still arm your Gagarin with continuity fails, so ensure you review the continuity results properly before launch. If you do not want this behaviour, you may use a Continuity Condition in a Rule within your Flight Configuration to prevent this.

Your deployment battery must be at least 6.7V in order for continuity detection to work. Your Gagarin will warn you if not.

Optionally you can record the location of the flight. If you are accessing your Gagarin via WiFi Station Mode you can click the Geolocate button to fill this in automatically.

Your browser will ask permission to share your location with your Gagarin. When asked click Allow or Yes, otherwise geolocation will fail.

Once you are ready to Arm, click the Unlock slider and press Arm within 3 seconds. If you wait longer you'll need to unlock it again. This prevents accidental arming.

Once armed, your Gagarin will not make a sound unless you've configured a Rule for this in your Flight Configuration. We recommend doing this for peace-of-mind.

There is no need to close your browser at this point, but there is no danger in doing so. If you remain connected to your Gagarin via WiFi, the Flight Control page will update itself continuously showing the battery, inputs and output continuity statuses. If you try to navigate away from the Flight Control page when armed, you will be warned that this will disarm your Gagarin. Closing your browser or disconnecting from WiFi will not affect your Gagarin's armed-state.

Your Gagarin can save and store many Flight Configurations at once, allowing you to preconfigure the behaviour you want ahead of your launch. Then, once you're on site and prepping your rocket you can activate the appropriate Flight Configuration without having to worry about working out or having to remember all the settings then-and-there.

You can add, edit, delete and activate Flight Configurations from the Flight Configurations page under the menu.

When creating a new Flight Configuration you have the option of choosing from some pre-made, quick-start examples or starting from scratch with a blank Flight Configuration. The quick-start examples not only demonstrate what is possible but also get you up and running quickly for common configurations.

Once you are editing/creating your Flight Configuration you need to give it a name - allowing you to reference this configuration from your others later on - and define the rules that make up the Flight Configuration.

A Rule has a Description - to let you know what the rule is for, a Trigger - an event that triggers the rule and an Action - something that happens when the Rule is triggered. An example of a Rule might be:

• Description: Drogue at Apogee
• Triggered by: Apogee
• Action: Turn Channel 1 on for 2000ms

The Trigger consists of the trigger type itself, an optional Delay, and any trigger-specific values.

Full list and descriptions of all triggers.

Triggers are what cause a Rule's Action to take effect, however only if certain Conditions are met. These conditions are defined per Rule and vary in parameters depending on the chosen Trigger.

When a certain Trigger has more than one Condition, they are logically ANDed.

Full list and descriptions of all conditions.

A Rule's Action is what to do once the Rule has been triggered.

Full list and descriptions of all actions.

Gagarin has 6 Output Channels plus a Beeper. The Beeper only automatically makes a sound on boot/wake up. If you want it to make a sound under any other conditions you must create a Rule for this.

This is the altitude above the pad at which to consider the rocket as having launched. You want this value to be high enough that winds and changing ambient pressure at ground level do not accidentally trigger this, but not so high as to affect the detection of other in-flight events (e.g. apogee).

This controls the PWM Freqency for any PWM Output Actions. All PWM output channels use this same frequency. The value must be between 10Hz and 40kHz

To save battery power when preparing your rocket, a common technique is to have a physical switch in series with your battery and flight electronics. This is a point of failure as well as added physical complexity which Gagarin avoids.

Enabling low-power mode causes Gagarin to power up using minimal battery power. When you are on the pad and ready to fly you can wake up GagarinGagarin and have it turn on all its peripheral hardware and begin functioning fully. This feature works using a capacitive touch sensor.

Run a wire from the Touch pin to the outside of the airframe on your electronics bay, usually by exposing a screw head on the outside of the airframe and connecting the wire to the inside. Keep the wire as short as possible and ideally away from other metallic (capacitive) items.

Fully assemble your electronics bay as you would for flight, power on your Gagarin (and any other devices in your electronics bay).

Observe the Touch Sensor Value bar under the Advanced settings in the Flight Configuration. Touch your finger on the exposed Touch Pin (e.g. screw head) and observe the change in the Touch Sensor Value. Repeat this a few times to get a good feel for what the finger-on vs finger-off values look like. Set the Detection Threshold slider to somewhere in bettwen the finger-on and finger-off values to calibrate the touch detector.

Warning: The capactive touch sensor is affected by nearby wires and objects - especially those connected to the same ground as the Gagarin. Don't configure the touch threshold in a setup that isnt inside your finalised rocket electronics bay, otherwise you may not be able to wake Gagarin due to changed environmental capacitance. If this happens you can force Gagarin to wake by shorting the PGM pins together. Do not keep them shorted together when powering Gagarin on else it will enter firmware flashing mode and not boot properly.

The next time you power on your Gagarin it will boot into Ultra-Low-Power mode and beep 3 times to indicate an ultra-low-power boot. To wake it, you must touch the Touch pin (in the same manner as you did during calibration) 5 times, it will beep on each touch to indicate a successful reading. Once awake, Gagarin will beep 6 times.

You can put your Gagarin back to sleep by touching the Touch Pin 5 times again. This will not work if your rocket is armed.

See the Power page for details on current consumption.

You can have Gagarin shut down non-flight critical peripherals (like WiFi) when armed by checking "Enter low-power mode when armed". 20s after arming, WiFi will be turned off. Your Gagarin will remain armed and flight-ready. To re-enable WiFi, you must touch the Touch Pin 5 times. You must have calibrated the sensitivity as above.

See the Power page for details on current consumption.

If you are accessing your Gagarin using Station mode (i.e. it's connected to an external WiFi hotspot such as your phone) then you can benefit from cloud backup. The Flight Configurations and Flight Logs screens will notify you if any of your data are not synced with your cloud backup and allow you to back them up.

In the sad event that your Gagarin is lost, you can re-download your data to a new unit without having to recreate them from scratch.

The complete Trigger consists of the trigger itself, an optional Delay, and any trigger-specific values.

The possible Triggers are:

Triggers when you arm the rocket for flight.

• You might want to use this to turn the Beeper on for an audible confirmation of successful arming, or maybe you turn a Channel on to activate a radio tracker or maybe you set the initial position of a servo.

This is launch detection.

• The Lift-Off trigger plus a Delay is useful for timed air-starts. For example use "Lift-Off plus 3000ms" to ignite a 2nd stage.
• Lift-Off is defined by the altitude of the rocket rising above the Launch Detection Altitude which defaults to 60 metres and can be adjusted under the Advanced Settings section of the Flight Configuration.
• Delays take the delay between real lift-off and Detected Lift-Off into account. For example, if your rocket is stationary on the pad, and then takes 0.1s to reach the Launch Detection Altitude after ignition and you have a Rule with a "Lift-Off plus 2000ms delay" trigger set up, the Rule will be triggered 1900ms after Lift-Off was detected (2000ms - 100ms = 1900ms). Unless you have a very slow lift off you can usually ignore this detection delay.

This is max-altitude detection.

• Apogee is defined as having encountered the maximum altitude over 1000ms ago.
• This will therefore be triggered 1000ms after Real Apogee.
• Delays take the delay between Real Apogee and Detected Apogee into account. For example, if you have a Rule with an "Apogee plus 1500ms delay" trigger set up, the Rule will be triggered 500ms after Apogee was detected (1500ms - 1000ms = 500ms).

This is an altitude threshold when descending, i.e. it will not trigger on ascent.

• The most common use-case for this is deploying your main parachute once the rocket has descended to a given altitude.
• If Apogee occurs at a lower altitude than a Descent Altitude Trigger you have set up, the trigger will immediately fire after Apogee Detection.
• You must provide an associated Trigger Altitude value.
• The Trigger Altitude is compared against the launch-pad altitude, not sea level. I.e. if you set a Trigger Value of 300m, this will be treated as 300m above the launch pad's altitude.

This is a minimum velocity threshold when descending. i.e. it will not trigger when ascending.

• This is useful as a failsafe, if your rocket is descending too fast you might want to fire separation charges or take other remedial action.
• You must provide an associated Trigger Velocity value.

There are two input channels on the Gagarin which can be used as Triggers for Rules. You might use these with a breakwire for separation detection or as an input from external hardware.

You can choose if you want to trigger when the input becomes closed i.e. the + and - pins of the input channel become connected together, or when it becomes opened, i.e. the + and - pins of the input channel becomes disconnected.

This is when the rocket has detected itself as landed.

Landing is defined as: after the rocket has descended to less than half the apogee altitude and the altitude does not change by more than 3 metres in 5 seconds.

Triggers are what cause a Rule's Action to take effect, however only if certain Conditions are met. These conditions are defined per Rule and vary in parameters depending on the chosen Trigger.

When a certain Trigger has more than one Condition, they are logically ANDed.

The following conditions can be defined for each trigger:

Inputs: Input conditions allow you to specify a input-state constraints. For example, to create a physical arm-interlock you could create a rule that disarms the rocket as soon as it's armed, if an Input isn't closed.

Continuity: This allows you to put a constraint on the continuity of your used (non PWM) output channels.

Inputs: Input conditions allow you to specify input-state constraints. For example, you may wish to only ignite a 2nd stage if a breakwire between the 1st and 2nd stages has been broken, indicating separation has occurred.

Continuity: This allows you to put a constraint on the continuity of your used (non PWM) output channels.

Altitude Threshold: This allows you to specify a minimum or maximum altitude constraint. This condition only makes sense when used with a Delay. For example, you may wish to ignite a 2nd stage 3000ms after lift off, but only if you're above a certain altitude.

Velocity Threshold: This allows you to specify a minimum or maximum velocity constraint. This condition only makes sense when used with a Delay. For example, you may wish to ignite a 2nd stage 3000ms after lift off, but only if you're above a certain velocity.

Inputs: Input conditions allow you to specify input-state constraints. This allows you to only trigger an action if the inputs are in the required states.

Continuity: This allows you to put a constraint on the continuity of your used (non PWM) output channels.

Altitude Threshold: This allows you to specify a minimum or maximum altitude constraint. For example, if Apogee of the upper stage of a two stage rocket has occurred too low (probably due to a flight problem like a failed air start), you can fire the main parachute immediately instead of waiting for descent.

Inputs: Input conditions allow you to specify input-state constraints. This allows you to only trigger an action if the inputs are in the required states.

Continuity: This allows you to put a constraint on the continuity of your used (non PWM) output channels.

Descent Velocity: This allows you to specific a minimum or maximum decent velocity when a given descent altitude is reached.

Inputs: Input conditions allow you to specify input-state constraints. This allows you to only trigger an action if the inputs are in the required states.

Continuity: This allows you to put a constraint on the continuity of your used (non PWM) output channels.

Descent Altitude: This allows you to specific a minimum or maximum decent altitude when a given descent velocity is reached.

Descent Velocity: This allows you to specific a minimum or maximum decent velocity when a given descent altitude is reached.

Descent Altitude: This allows you to specific a minimum or maximum decent altitude when a given descent velocity is reached.

Inputs: Input conditions allow you to specify input-state constraints. For Input triggers, you can only specify input constraints for the other inputs on the device. This allows you to only trigger an action if the inputs are in the required states.

Continuity: This allows you to put a constraint on the continuity of your used (non PWM) output channels.

Inputs: Input conditions allow you to specify input-state constraints. This allows you to only trigger an action if the inputs are in the required states.

Continuity: This allows you to put a constraint on the continuity of your used (non PWM) output channels.

A Rule's Action is what to do once the Rule has been triggered.

The possible Actions are:

This turns an output channel on.

• You must specify which Channel to turn on
• The Channel will stay on until the rocket is disarmed or another Action turns it off. Landing does not automatically turn Channels off.
• Another Rule's Action can turn it back off
• If a Channel is already on when the Turn Channel On Action is applied to it, the Channel will remain on, this does not cause a problem.
• This is useful for activating external electronics or trackers

This turns an output channel off.

• You must specify which Channel to turn off
• Another Rule's Action can turn it back on. Landing does not automatically turn a Channel off. If you want this to happen you must create an appropriate Rule.
• If a Channel is already off when the Turn Channel Off Action is applied to it, the Channel will remain off, this does not cause a problem.

This turns a Channel on for a defined period of time, and then turns it off again.

• This is the recommended Action for e-match ignition, typically enabling the Channel for 2000ms is enough to ignite most e-matches, although test this with your chosen brand.
• You must define the On-duration
• If a Channel is already on when the Turn Channel On Then Off Action is applied to it, the Channel will remain on for the On-Duration, but will then be turned off. It will not stay on because it was already on.
• Beware advanced configurations with overlapping two On-Off actions for the same channel in time. For example, if you have an action to turn channel 1 On for 2000ms and then Off and this fires at Apogee, but then you have another On-Off rule to fire at Apogee + 500ms, the on-duration of the second action could be cut short as the first one elapses and turns off.

This will output a PWM signal at the given duty cycle and frequency

• You must provide the Channel and Pulse Width for the Action. The PWM Freqency is controlled under Advanced Settings for the Flight Configuration, meaning all PWM output channels use the same frequency.
• You cannot mix On/Off Actions with PWM Actions for a given channel.

This will turn the beeper on constantly.

This will turn the beeper off.

This will cause the beeper to beep n times and then stop.

This will cause the beeper beep out the maximum altitude achieved in the flight. If the apogee altitude was 802m, it would beep 8 times, pause slightly, beep 10 times (signifying a zero), pause slightly, beep 2 times, pause for a longer time, then repeat ad infinitum.

This will will disarm your rocket. This action can only be used with the Armed trigger and a Condition set. Use this to "prevent" arming under undesired conditions by immediately disarming the rocket when arming is attempted.

The Flight Logs page lets you review the flight data from all previous flights, as well as showing you the total used and remaining flight log space.

Once you have recovered your Gagarin after flight, we recommend accessing the Flight Log page as soon as possible with your device in WiFi Station Mode. From the Flight Log page you will be prompted to backup the new flight log to cloud storage where it will be safely stored for ever.

Click the View button next to the Flight Log you wish to view.

From here you can download the flight data as CSV, view the flight telemetery and see a detailed event log of everything that happened (or didnt in the case of Flight Configuration Rules with Conditions) during the flight.

The Flight Details section shows you a summary of the flight information and lets you download the flight data as a CSV.

The Visualisation section shows a graph of your rockets altitude and speed from just before launch to 5 seconds after landing.

Additionally if your Flight Configuration utilises input channels, the state of the used channels is shown throughout the flight.

You can toggle the visibility of annotations showing the actions taken and the events that occured. Note that actions/events which occurred long before launch (e.g. arming) are not shown on the graph.

Here we can see a simple flight, showing the drogue (Channel 1) being fired at apogee and the main (Channel 2) being fired at 150m. The rocket contained a breakwire across the main section connected to Input 1, you can see from the graph how this breaks as the main charge separates the two halves of the rocket.

The continuity bars show when continuity was lost for each channel. This is useful for debugging failed flights when continuity was lost unexpectedly.

Note that input states are only logged if they feature in the flight configuration.

The Stats section shows you the key metrics of the flight.

The Configuration section shows you what happened with each Rule during the flight. This can be extremely useful for debugging.

Here we can see that our first four rules were triggered, but our Emergency freefall main rule didn't trigger as we didn't descend fast enough - a good thing in this case.

The event log details everything Gagarin either did or tried to do, and the telemetry from that moment in time.

Here we can see the event log from a simple flight with a drogue at apogee and a main at 150m/500ft.

In the event that your Gagarin is running low on storage, you can delete previous flight logs. We recommend enabling Cloud Backup before you do this, as your logs can be preserved for ever without worring about local storage issues. When connected to the Internet you can view all previous logs made with your Gagarin. Logs which exist only in cloud backup and not on your device will show in the Flight Log list, but do not take up any space on the device.

By default, your Gagarin will show it's unique MAC address at the top, allowing you to diffrentiate one Gagarin you own from another.

These seemingly random collection of letters and number howwver are not that memorable, and two devices you own may have very similar MAC addresses. If you have two Gagarins in one rocket you might easily get confused as to which is which.

To combat this, you can give your device a nickname which will then show at the top in place of the MAC address.

The Dashboard of your Gagarin will show you the voltages of the Deployment Battery and Battery. The accuracy of these measurements depend on accurate resistance reading of electronic components (resistors) on the device itself. See the Power page for a detailed description and explanation of what to do here.

Gagarin supports connecting to Shepard which can relay flight telementry and output events to your ground station (Goddard), forwarding all flight information. You can either connect your Gagarin and Shepard via UART (see I/O page for details) or have them communicate over Bluetooth. The advantage of Bluetooth is that Shepard can concurrently pair with upto 3 Gagarins where as UART is limited to 1, and you don't need wires, meaning you can physically separate the devices and have them still communicate.

Shepard will automatically discover and connect to enabled Gagarins, provided they share the same PIN number. Choose a random 6 digit PIN and enter this into your Gagarin and Shepard.

Note that a Gagarin can only connect to one Shepard at a time.

Do not enable the Bluetooth functionality if you won't be using it, as this will put additional, unnecessary load on your battery.

Gagarin can integrate directly with UKRA's Members Portal and Flight Logging tool, to enable Gagarin's flight log data to be directly attached to a flight in your UKRA Flight Log.

Visit https://members.ukra.org.uk/account/security and generate an API key. Copy and paste it into the Settings page on your Gagarin.

Then from the View Flight Log page, use the ⋮ menu to "Upload to UKRA".

To save battery power when preparing your rocket, a common technique is to have a physical switch in series with your battery and flight electronics. This is a point of failure as well as added physical complexity which Gagarin avoids.

Enabling low-power mode causes Gagarin to power up using minimal battery power. When you are on the pad and ready to fly you can wake up Gagarin and have it turn on all its peripheral hardware and begin functioning fully. This feature works using capacitive touch functionality.

Run a wire from the Touch pin to the outside of the airframe on your electronics bay, usually by exposing a screw head on the outside of the airframe and connecting the wire to the inside. Keep the wire as short as possible and ideally away from other metallic (capacitive) items.

Fully assemble your electronics bay as you would for flight, power on your Gagarin (and any other devices in your electronics bay).

Visit the settings page for Gagarin and observe the Touch Sensor Value bar. Touch your finger on the exposed Touch Pin (screw head) and observe the change in the Touch Sensor Value. Repeat this a few times to get a good feel for what the finger-on vs finger-off values look like. Set the Detection Threshold slider to somewhere in bettwen the finger-on and finger-off values to calibrate the touch detector.

The next time you power on your Gagarin it will boot into Low-Power mode and beep 3 times to indicate a low-power boot. To wake it, you must touch the Touch pin (in the same manner as you did during calibration).

See the Power page for details on current consumption.

Each of the 6 outputs on your Gagarin can be controlled independently and are numbered 1-6. Outputs need not be used for a predetermined purpose (e.g. Drogue parachute), you can use any channel for any purpose. This can be useful for cable routing, allowing you to use the most convenient terminals for your application.

You should connect your ignitor between then + and - terminals labelled for the output channel, do not share a ground directly with your battery. The -ve terminal of the output is electronically switched as well as the +ve, providing extra safety on the pad.

If you want to use the output to trigger logic on an external device, e.g. turn a radio transmitter on, you should ensure you have a common ground to avoid floating-ground issues.

This feature is still under development, contact your vendor before purchase if you will rely on this feature.

Gagarin can drive any of the common 1-wire chainable LED chipsets:

• Neopixel / WS2811 / WS2812(B) / WS2813
• TM1809/4
• TM1803
• UCS1903
• GW6205

Gagarin ships with a number of predefined effects.

This calculator is useful for working out the power requirements for your LEDs.

You should ensure the ground pin is shared between your LEDs' power supply and Gagarin to avoid floating-ground issues.

The LED output data pin connects directly to the GPIO port of the microcontroller, so take care not to do anything to damage the MCU. There is no series resistor in place which is sometimes useful for anti-ringing and current limiting purposes. This article provides some good insight into the necessity of a series resistor.

Inputs can be used as triggers to affect actions or as conditions on other triggers, giving you huge flexibility to produce complex flight configurations.

The inputs can be configured to respond to being Closed (+ and - becoming connected together) and Opened (+ and - being disconnected from each other).

You should only connect one input's + and - together, do not connect them to anything else.

The Touch pin is used for waking your Gagarin from low-power mode. See the Power page for more information on this.

Gagarin exposes a standard UART/Serial port running at 115200 baud.

Connect an FTDI UART (or similar) adaptor at 3.3V to the Gnd, Tx and Rx pins.

Gagarin will output a host of information on boot and during use which can be helpful to advanced users when debugging issues.

Gagarin can be connected to other Trullock Aerospace devices (e.g. Shepard) in order to relay flight information back to the ground.

This can be achieved in either wired mode, using the UART pins, or wireless mode using Bluetooth. We recommend the latter as there is less chance of wiring failures.

For wired interconnectivity, connect the Tx pin from Shepard to the Rx pin on Gagarin, and the Rx pin from Shepard to the Tx pin on Gagarin. Connect the Gnd pin from Gagarin to the Gnd pin on Shepard.

See the Specifications page for the pinout information.

You can access the firmware update page via the Update button on the Device Info page accessible via the menu.

If you are connected to WiFi via Station mode and a new firmware version is available, you will be given the option to automatically update.

If you are connected to WiFi via Station mode you can rollback to a previous firmware version. You should only need to do this if you are experiencing issues with a newer version. Contact your vendor before going down this route.

You can perform a factory reset from the firmware update page.

This will clear all data from your device and reset all your settings, as well as rolling back to the stock firmware the device shipped with.

If you are unable to connect to your device you can initiate a factory reset by shorting the Factory Reset (Rst) pads on the board. Note that you need to use a good conductor to short the pads, and ensure they are well connected to the pads. If you experience issues here you can try tinning the pads with a little solder to provide a more conductive surface.

Gagarin creates its own 2.4GHz WiFi access point which you can connect to using any modern device. You can either set Gagarin to use the its default access point SSID, or have it use the device's nickname, or have it be the current active flight configuration. Note that you should choose a memorable password as the last setting will cause the SSID to change.

Gagarin will also attemp to connect to upto 3 WiFi access points as a station. When you are not connected to Gagarin's access point, it will periodically attempt to connect to each saved access point in order.

Gagarin's access point is still available when it is connected as a station to an external access point. However, be aware that if you connect to Gagarin's Access Point before it has connected to any external Access Points, it will not attempt to do so. If you need both modes of operation at once, ensure your external Access Point is on and working before powering on Gagarin.

You should not connect Gagarin to any WiFi network that you do not have complete control over. For example, do not connect it to a public WiFi network at a launch site as any other users of the network will be able to control your device, potentially changing the configuration or firing output channels.

Grissom is a WiFi controlled flight computer with an advanced but simple to use interface.

It provides ample features for the most advanced use-cases, whilst supporting simple setup and use through a clean and modern web-based interface.

Configure, arm, disarm and view flight log all online without any custom apps, hardware or cables.

Connect via your phone's WiFi hotspot to benefit from additional features such as free cloud backup of configurations and flight logs and geolocation.

The extremely detailed flight log viewer shows the most detailed breakdown of flight events of any computer on the market, making debug and diagnostics very easy.

• IMPORTANT Grissom users on a firmware version below 1.2.241 MUST update to 1.2.241 before updating to 1.3.x or above in order to fix a bug with firmware updating.
• Descent Velocity triggers currently occur after just one speed sample exceeds the set threshold. If you have a particularly noisy descent, either due to vent-hole effects or other buffeting, you may get speed spikes which exceed this threshold but do not reliably indicate a fast, sustained descent. We recommend either not using this mode until a future firmware update is released which add additional smoothing/sampling, or use a high threshold value.
• Some captive browsers (the browser you get when connecting to Grissom by clicking Sign In To WiFi) do not handle file downloads very well. If you are connected in this way and are struggling to download flight logs, try connecting directly using your normal browser. See the Quickstart guide for connectivity advice.

If you need more outputs or input channels check out Gagarin.

Warranty

The devices are provided "as-is" and we make no warranties, whether express, implied, or statutory, regarding or relating to the products or any materials or services furnished or provided. To the fullest extent allowed by law, we specifically disclaim all implied warranties of title, merchantability, non-infringement, and fitness for a particular purpose (even if we has been informed of such purpose).

The devices we provide are part-assembled and therefore we have not performed any testing to ensure their function in accordance with any expectations or ensured they are fit for any particular purpose. It is the end user's responsibility to ensure the final, assembled device along with any firmware installed functions as they would expect and the end user assumes all liability for the use of the device and any outcomes from using the device.

The firmware provided is for demonstration purposes only and we make no warranties, whether express, implied, or statutory and we specifically disclaim all implied warranties of title, merchantability, non-infringement, and fitness for a particular purpose.

Compliance statement

The Grissom hardware is an educational device intended to help you learn how to build similar devices. The devices come part assembled for any reseller or end user to finalise. The devices come with no system on chip attached however one is provided with example firmware for demonstration purposes only.

Not a product

CE/UKCA: What we sell is very specifically a "part-assembled PCB", a "component", and not itself a "finished product". It has no case, leads, or power supply. Whilst the example system on chip provided has a CE mark in itself, we don't make any CE/UKCA conformance statement for this as a product as it is not a product. If someone resells/installs these devices in a form closer to the definition of a product then they need to ensure compliance with legislation.

Other regulations: It is unclear if the UK law: The Product Security and Telecommunications Infrastructure Act 2022, and The Product Security and Telecommunications Infrastructure (Security Requirements for Relevant Connectable Products) Regulations 2023 apply here or not. As we say, it is not a "finished product". However, just in case it does apply, this statement is an attempt to meet the requirements.

As the Grissom hardware can be assembled and distributed by anyone, obviously, if they make it, they have to consider compliance, so this statement only applies to cases where we have made the Grissom hardware, which we do not do anyway.

The product (if somehow it is deemed a product)

As the Grissom hardware is a general purpose module / circuit, it only really makes sense to make any statement about it "as supplied", which is with the demonstration Grissom software pre-loaded for your convenience.

If you choose to load any other software, or even build a variation of the Grissom software with your own (or someone else's) changes, then it is no longer "as supplied", and you now have a different "product" (if it is a "product") that you have made, so compliance is then up to you.

Type/batch

So, the "product" (which it isn't) is the software provided on the demonstration system on chip, all batches and builds, on the Grissom hardware made and supplied by Ivelop Consulting Ltd, and "as supplied", or as updated from the OTA server.

Who

The software is made by Andrew Bullock, and other open source contributors. However, I can only speak for me (Andrew Bullock), I have no idea if any and all OS library contributors also need to make a compliance statement.

When Ivelop Consulting Ltd manufactures and distributes boards, its name is "Ivelop Consulting Ltd", UK company 14434046, and its registered office address is 4 Cross Street, Beeston, Nottingham, Nottinghamshire, United Kingdom, NG9 2NX.

Statement made by manufacturer

The hardware covered here is made by/for Ivelop Consulting Ltd. This statement is prepared by Andrew Bullock, director Ivelop Consulting Ltd, on behalf of the "manufacturer".

Compliance

It is the opinion of the manufacturer that we have complied with Schedule 1 & 2, and 5.1-1 of ETSI EN 303 645. Specifically that where passwords are used, they are user specified, and that we have a vulnerability disclosure policy, etc.

• Normal web access to controls for your device have no passwords.
• Access to settings can have no password, or can have a user specified password.

Vulnerability disclosure policy

Please raise any security issue by contacting us. I would expect to reply promptly but at the very least within one month, and will reply to provide any status updates. As the demonstration software provided is free with no contract or warranty, saying I'll reply in a month is not a contractual statement. In practice I usually reply within hours.

Please note that not all issues are security issues, and this policy applies only to "security issues".

Support / updates

Updates are made via an OTA server.

Support period

I plan to continue to support this product until I get bored, or drop dead, whichever is sooner. I expect that to be many more years.

Issued

2024-09-19

Processor

First, you should attach the processor. Position it so that all the castellations neatly line up with the receiving pads. Hold the processor in place with some tape. Using a fine tipped soldering iron and fine flux-cored solder, work your way around the castellations, flowing solder into the joint.

The Red pins are attached to the ground plane and will require much more heat from your iron to get them up to soldering temperature, we recommend you do these pins last.

We recommend starting with the Blue pin, followed by the Yellow pin. If you do not alternate the sides initially, soldering all along one side can cause the processor to lift up, creating a gap on the opposite side.

Use a mignifying eyepiece to fully inspect each solder joint and ensure all are properly and cleanly connected with no bridged pins.

It is not necessary to solder the ground pad (Green) underneath the processor, but a small blob of thermal conductive paste won't hurt.

Processor positioning

System test

Before you attach the next components you should power up the board and navigate to the system-test page (under Menu -> Device info -> System test) and ensure you are getting a reading from the altimeter. If it is reading 0m constantly then there is a problem with your board. Check the soldering joints on the processor. If the problem remains please contact your vendor for assistance.

Rectifier

The orientation for the rectifier should be obvious. Ensure you properly solder the tab and both legs properly.

Rectifier positioning

Through-hole components

Attach the buzzer (blue cricle), getting the correct orientation (note the + marked on the board and component).

Attach the FET (red rectangle). Note that the metal tab on the back of the component faces outwards (to the right on the picture), away from the power terminals.

Attach the output/touch connector block (green rectangle), ensure it is properly seated and the right way around before soldering all pins.

Through-hole component positioning

System test

Power up the board and navigate to the system-test page (under menu -> Device info -> System test) and ensure you are still getting a reading from the altimeter. If it is reading 0m constantly then there is a problem with your board. Check the soldering joints on the processor. If the problem remains please contact your vendor for assistance.

Perform a system-test with indicator loads (we recommend mini 9V filament bulbs) on the output channels and ensure they all fire properly.

If you purchased your Grissom as a kit you will first need to assemble it.

Next you need to decide how you're going to power your Grissom. Fully read the Power documentation to avoid damaging your device.

When you power your Grissom up, it will make 3 beeps if booting into ultra-low-power mode, and 6 beeps when it boots up fully either directly or by being woken from ultra-low-power mode. If it makes 2 beeps, looping indefinitely then there is a hardware issue and you should contact your vendor. Do not fly your device in this state.

Once your Grissom is assembled and powered up, it will create a WiFi Access Point which you can connect to with any compatible device.

The WiFi SSID will be of the form "Grissom AABBCC", where AABBCC is a unique ID for device. The default password is blank, you should change this straight away once connected.

Use the WiFi settings on your phone/laptop to connect to your Grissom's Access Point. After you connect, your phone/laptop will tell you to "Sign In" to the WiFi network. This is a feature of WiFi networks that allows a webpage to be opened immediately after connecting. Usually this is used by public WiFi networks to authenticate you. Here it's used as a convenience so you don't need to remember or type in an IP addresses to get started. If this message doesn't pop up automatically, there should be a Sign In button in your device's WiFi settings page to click.

If your device says something to the effect of "This network does not provide Internet connectivity, do you want to stay connected?" Choose Yes, otherwise you will be disconnected and have to start again.

Some devices' default behaviour is to automatically disconnect you from WiFi networks that do not provide Internet connectivity. If you are struggling with this, disable your cellular Internet.

The first thing you will see on the device's Flight Control page is a warning about insecure WiFi.

Click the Configure Connectivity button to fix this.

Provide a memorable password for the device's Access Point to secure it against unwanted users. If you forget this and can't otherwise connect to your device you'll need to do a Factory Reset.

We strongly advise using your Grissom in Station mode. This means having it connect to another WiFi network such as one hosted by your phone's hotspot. This gives your device the ability to talk to the Internet and as such you get additional features: cloud backup of Flight Configurations and Flight Logs, Firmware updates and Geolocation.

The access point must be 2.4GHz, if using your phone's hotspot you may need to enable "Enhanced compatability mode" or similarly named feature to activate 2.4GHz mode.

The changes you make to your WiFi settings will not take effect until you have disconnected from Grissom.

When you come to use Grissom again you will either need to connect to the device's Access Point using the password you just created, or connect to it via the external WiFi network whos details you provided. To do this:

1. If your connected device supports mDNS (most do, but it can be flakey) you can visit http://grissom_aabbcc.local (where aabbcc are the same as the device's Default Access Point SSID)
2. If (1) doesn't work or mDNS is not available, you need to connect to your device by it's IP Address. To find this, you have 3 options:
   • Connect to your Grissom's Access Point and goto the Device Info page under the main menu. Here it will tell you the device's Station IP (it can be connected to an access point and BE an access point at the same time). Make a note of this, disconnect from the Grissom's Access Point and reconnect to the same network as the Grissom and then visit that IP Address in your browser.
   • Consult your WiFi's router DHCP table to find the IP it gave your Grissom
   • Connect a UART adaptor to the Gnd, Rx, Tx pins and observe the Serial output on boot, it will report it's Station IP.

Technical Note: all internet based features are performed client-side in the browser, so only the client device (e.g. your phone/laptop) need internet access, but it also needs access to Grissom at the same time. This is why connecting both Grissom and your client device to the same Access Point is desirable.

If you are connected to your Grissom in Station Mode, you may see an "Update available" hint. We recommend connecting this way at least initially and then periodically over time in order to check for updates which are published regularly.

If you see this, follow the onscreen instructions to update your device to the latest firmware to benefit from bug fixes and new features. You should not fly on out-of-date firmware.

See the Flight configurations page on exactly how to create a Flight Configuration.

Once you have activated a Flight Configuration, you're ready to do a bench test.

With a Flight Configuration activated, arm your device by clicking the Unlock slider and within 3 seconds press the Arm button.

Place one end of a drinking straw over the barometer on the board creating a reasonable seal. Suck the other end of the straw for as long as you can, first quickly increasing the suction and then gently releasing it, simulating the pressure change curve of a real flight.

5 seconds after the pressure has stabilised back to room conditions the device will automatically disarm and the Flight Control page will update accordingly.

You can then navigate to the Flight Log for the flight and correlate what it says the "flight" looked like and what events occured with what really happened to the output channels on your bench.

Hopefully everything happened as expected. Use this methodology to become familiar with Flight Configurations and their Rules before your first real flight.

12V is the absolute maximum voltage you should apply to the Battery terminals and 24V is the maximum you should apply to the Deployment Battery terminals.

5V is the minimum you should provide to the Battery terminals.

We recommend using at least a 400mAh 2S LiPo, which should last around 3 hours. If you need to use a smaller capacity LiPo we recommend enabling ultra-low-power boot mode to save battery.

7.4V (2S LiPo) is the minimum recommended voltage for the Deployment Battery. You can use less, but the continuity tests will not function correctly unless you have at least 6.7V for a zero resistance load (ignitor).

If you are testing on a bench power supply, we recommend using no more than 7V.

You need to consider the power dissipation of the onboard voltage regulator, the higher voltage battery you use the more power (heat) the regulator will have to dissipate. Ensure you mount your Grissom so there is room for air to circulate under the board.

We do not recommend 9V PPP batteries as they cannot supply enough current to the ignitors and avoid CPU brownout.

If you want to use a single battery for both the logic and deployment, solder-bridge the "D. BATT Jumper" on the top of the board. We do not recommend putting two wires into a single screw-terminal connector as it can fail to grip properly, resulting in power loss mid-flight.

You should not power-up the Deployment Battery before the Battery, otherwise continuity tests and activation of the output channels may not function correctly.

With WiFi running and active connected clients (e.g. your smartphone whilst setting up your device) current consumption is approx. 140mA.

Typically flight electronics are enabled at the pad with a physical switch. Grissom gives you the option to eliminate this point of failure by allowing you to boot the device into ultra-low-power mode, and then awaken it at the pad using a capacitive touch input. When in ultra-low-power mode current consumption is approx. 7mA. See Flight Configurations for more info.

You can additionally reduce power consumption by enabling low-power mode when Armed. In this mode, about 77mA is consumed. See Flight Configurations for more info.

The Dashboard of your Grissom will show you the voltages of the Deployment Battery and Battery.

You can improve the accuracy of the voltage measurements by providing exact resistances for 4 resistors.

Measure the resistances of R6, R7, R8 and R9 and record their exact resistences with the board unpowered.

Hardware version 1.1.x

Once your board is assembled and up and running, navigate to the Settings page and input the measured values. This will provide improved voltage reporting. Be accurate, even a small resistance deviation can produce meaningful measurement differences.

The PCB is 26.3mm x 52.7mm made from 1.6mm FR-4.

The mounting holes are 3mm diameter at 19.5mm x 46.5mm centres.

Fully populated, the device weighs approx. 11g.

The brain of Grissom is an ESP32, dual-core, 240MHz, 32bit Xtensa LX6 microprocessor. It is designed to achieve the best power and RF performance, showing robustness, versatility and reliability in a wide variety of applications and power scenarios. It communicates via WiFi 802.11b/g/n in the unlicensed 2.4GHz. To comply with radio licensing laws you should build Grissom exactly as specified and not modify the radio module in any way.

The output channels are individually driven by dedicated high-side grounded-load drivers (VN5E160STR-E). These have an internal current limiting feature of 10A, which is more than enough to power a hot-wire cutter for several seconds. Additional protection is provided by a MOSFET (NTD3055L104-1G) which isolates the negative connections of all the outputs until the device is armed.

Settings, Flight logs and Flight configurations are stored in the onboard NAND flash chip. This has an expected block-write-lifetime of 10,000 cycles which does put a finite lifespan on the device. The file system employs a wear-leveling algorithm to reduce flash wear and so this is unlikely to be a practical problem. If you had one flight a day, every day, we wouldn't expect this to be a problem within 3000 years.

The ground test page allows you to directly control the output channels of your Grissom. This is useful for ensuring all your outputs are working properly and for testing ejection charges.

You can test:

• Output: Turn on then off
• Output: PWM
• Beeper: Beep n times
• LEDs

The continuity status of a selected output will be tested and shown. The continuity will either pass or fail. If the Deployment Battery voltage is insufficient, testing cannot happen.

Once you are ready to test, click the Unlock slider and press Conduct Test within 3 seconds. If you wait longer you'll need to unlock it again. This prevents accidental testing.

This is the main page of your Grissom and is where you arm it for flight.

In order to fly you'll need/want to:

Click the Manage button under the Flight Configurations box to create a new or activate an existing Flight Configuration.

Your Grissom will boot up with the previously activated Flight Configuration re-activated and ready to go.

The flight computer and deployment battery voltages are shown. They will be highlighted red if they are of a value that is low for a LiPo battery.

You will not be able to fly if you don't have enough free log space. Go to Flight Logs and delete some old logs if this is affecting you (See Flight Logs section for more information).

If your active Flight Configuration turns output channels on or off, their continuity status will be shown for you to review and ensure they are as expected.

Your Grissom will warn you if used output channels do not have continuity. This may be a false alarm for high-resistance hot-wire-cutters or other electronic components. Do bench tests and understand what your expected continuity results are.

You can still arm your Grissom with continuity fails, so ensure you review the continuity results properly before launch. If you do not want this behaviour, you may use a Continuity Condition in a Rule within your Flight Configuration to prevent this.

Your deployment battery must be at least 6.7V in order for continuity detection to work. Your Grissom will warn you if not.

Optionally you can record the location of the flight. If you are accessing your Grissom via WiFi Station Mode you can click the Geolocate button to fill this in automatically.

Your browser will ask permission to share your location with your Grissom. When asked click Allow or Yes, otherwise geolocation will fail.

Once you are ready to Arm, click the Unlock slider and press Arm within 3 seconds. If you wait longer you'll need to unlock it again. This prevents accidental arming.

Once armed, your Grissom will not make a sound unless you've configured a Rule for this in your Flight Configuration. We recommend doing this for peace-of-mind.

There is no need to close your browser at this point, but there is no danger in doing so. If you remain connected to your Grissom via WiFi, the Flight Control page will update itself continuously showing the battery, inputs and output continuity statuses. If you try to navigate away from the Flight Control page when armed, you will be warned that this will disarm your Grissom. Closing your browser or disconnecting from WiFi will not affect your Grissom's armed-state.

Your Grissom can save and store many Flight Configurations at once, allowing you to preconfigure the behaviour you want ahead of your launch. Then, once you're on site and prepping your rocket you can activate the appropriate Flight Configuration without having to worry about working out or having to remember all the settings then-and-there.

You can add, edit, delete and activate Flight Configurations from the Flight Configurations page under the menu.

When creating a new Flight Configuration you have the option of choosing from some pre-made, quick-start examples or starting from scratch with a blank Flight Configuration. The quick-start examples not only demonstrate what is possible but also get you up and running quickly for common configurations.

Once you are editing/creating your Flight Configuration you need to give it a name - allowing you to reference this configuration from your others later on - and define the rules that make up the Flight Configuration.

A Rule has a Description - to let you know what the rule is for, a Trigger - an event that triggers the rule and an Action - something that happens when the Rule is triggered. An example of a Rule might be:

• Description: Drogue at Apogee
• Triggered by: Apogee
• Action: Turn Channel 1 on for 2000ms

The Trigger consists of the trigger type itself, an optional Delay, and any trigger-specific values.

Full list and descriptions of all triggers.

Triggers are what cause a Rule's Action to take effect, however only if certain Conditions are met. These conditions are defined per Rule and vary in parameters depending on the chosen Trigger.

When a certain Trigger has more than one Condition, they are logically ANDed.

Full list and descriptions of all conditions.

A Rule's Action is what to do once the Rule has been triggered.

Full list and descriptions of all actions.

Grissom has 2 Output Channels plus a Beeper. The Beeper only automatically makes a sound on boot/wake up. If you want it to make a sound under any other conditions you must create a Rule for this.

This is the altitude above the pad at which to consider the rocket as having launched. You want this value to be high enough that winds and changing ambient pressure at ground level do not accidentally trigger this, but not so high as to affect the detection of other in-flight events (e.g. apogee).

This controls the PWM Freqency for any PWM Output Actions. All PWM output channels use this same frequency. The value must be between 10Hz and 40kHz

To save battery power when preparing your rocket, a common technique is to have a physical switch in series with your battery and flight electronics. This is a point of failure as well as added physical complexity which Grissom avoids.

Enabling low-power mode causes Grissom to power up using minimal battery power. When you are on the pad and ready to fly you can wake up Grissom and have it turn on all its peripheral hardware and begin functioning fully. This feature works using a capacitive touch sensor.

Run a wire from the Touch pin to the outside of the airframe on your electronics bay, usually by exposing a screw head on the outside of the airframe and connecting the wire to the inside. Keep the wire as short as possible and ideally away from other metallic (capacitive) items.

Fully assemble your electronics bay as you would for flight, power on your Grissom (and any other devices in your electronics bay).

Observe the Touch Sensor Value bar under the Advanced settings in the Flight Configuration. Touch your finger on the exposed Touch Pin (e.g. screw head) and observe the change in the Touch Sensor Value. Repeat this a few times to get a good feel for what the finger-on vs finger-off values look like. Set the Detection Threshold slider to somewhere in bettwen the finger-on and finger-off values to calibrate the touch detector.

Warning: The capactive touch sensor is affected by nearby wires and objects - especially those connected to the same ground as the Grissom. Don't configure the touch threshold in a setup that isnt inside your finalised rocket electronics bay, otherwise you may not be able to wake Grissom due to changed environmental capacitance. If this happens you can force Grissom to wake by shorting the PGM pins together. Do not keep them shorted together when powering Grissom on else it will enter firmware flashing mode and not boot properly.

The next time you power on your Grissom it will boot into Ultra-Low-Power mode and beep 3 times to indicate an ultra-low-power boot. To wake it, you must touch the Touch pin (in the same manner as you did during calibration) 5 times, it will beep on each touch to indicate a successful reading. Once awake, Grissom will beep 6 times.

You can put your Grissom back to sleep by touching the Touch Pin 5 times again. This will not work if your rocket is armed.

See the Power page for details on current consumption.

You can have Grissom shut down non-flight critical peripherals (like WiFi) when armed by checking "Enter low-power mode when armed". 20s after arming, WiFi will be turned off. Your Grissom will remain armed and flight-ready. To re-enable WiFi, you must touch the Touch Pin 5 times. You must have calibrated the sensitivity as above.

See the Power page for details on current consumption.

If you are accessing your Grissom using Station mode (i.e. it's connected to an external WiFi hotspot such as your phone) then you can benefit from cloud backup. The Flight Configurations and Flight Logs screens will notify you if any of your data are not synced with your cloud backup and allow you to back them up.

In the sad event that your Grissom is lost, you can re-download your data to a new unit without having to recreate them from scratch.

The complete Trigger consists of the trigger itself, an optional Delay, and any trigger-specific values.

The possible Triggers are:

Triggers when you arm the rocket for flight.

• You might want to use this to turn the Beeper on for an audible confirmation of successful arming, or maybe you turn a Channel on to activate a radio tracker or maybe you set the initial position of a servo.

This is launch detection.

• The Lift-Off trigger plus a Delay is useful for timed air-starts. For example use "Lift-Off plus 3000ms" to ignite a 2nd stage.
• Lift-Off is defined by the altitude of the rocket rising above the Launch Detection Altitude which defaults to 60 metres and can be adjusted under the Advanced Settings section of the Flight Configuration.
• Delays take the delay between real lift-off and Detected Lift-Off into account. For example, if your rocket is stationary on the pad, and then takes 0.1s to reach the Launch Detection Altitude after ignition and you have a Rule with a "Lift-Off plus 2000ms delay" trigger set up, the Rule will be triggered 1900ms after Lift-Off was detected (2000ms - 100ms = 1900ms). Unless you have a very slow lift off you can usually ignore this detection delay.

This is max-altitude detection.

• Apogee is defined as having encountered the maximum altitude over 1000ms ago.
• This will therefore be triggered 1000ms after Real Apogee.
• Delays take the delay between Real Apogee and Detected Apogee into account. For example, if you have a Rule with an "Apogee plus 1500ms delay" trigger set up, the Rule will be triggered 500ms after Apogee was detected (1500ms - 1000ms = 500ms).

This is an altitude threshold when descending, i.e. it will not trigger on ascent.

• The most common use-case for this is deploying your main parachute once the rocket has descended to a given altitude.
• If Apogee occurs at a lower altitude than a Descent Altitude Trigger you have set up, the trigger will immediately fire after Apogee Detection.
• You must provide an associated Trigger Altitude value.
• The Trigger Altitude is compared against the launch-pad altitude, not sea level. I.e. if you set a Trigger Value of 300m, this will be treated as 300m above the launch pad's altitude.

This is a minimum velocity threshold when descending. i.e. it will not trigger when ascending.

• This is useful as a failsafe, if your rocket is descending too fast you might want to fire separation charges or take other remedial action.
• You must provide an associated Trigger Velocity value.

This is when the rocket has detected itself as landed.

Landing is defined as: after the rocket has descended to less than half the apogee altitude and the altitude does not change by more than 3 metres in 5 seconds.

Triggers are what cause a Rule's Action to take effect, however only if certain Conditions are met. These conditions are defined per Rule and vary in parameters depending on the chosen Trigger.

When a certain Trigger has more than one Condition, they are logically ANDed.

The following conditions can be defined for each trigger:

Continuity: This allows you to put a constraint on the continuity of your used (non PWM) output channels.

Continuity: This allows you to put a constraint on the continuity of your used (non PWM) output channels.

Altitude Threshold: This allows you to specify a minimum or maximum altitude constraint. This condition only makes sense when used with a Delay. For example, you may wish to ignite a 2nd stage 3000ms after lift off, but only if you're above a certain altitude.

Velocity Threshold: This allows you to specify a minimum or maximum velocity constraint. This condition only makes sense when used with a Delay. For example, you may wish to ignite a 2nd stage 3000ms after lift off, but only if you're above a certain velocity.

Continuity: This allows you to put a constraint on the continuity of your used (non PWM) output channels.

Altitude Threshold: This allows you to specify a minimum or maximum altitude constraint. For example, if Apogee of the upper stage of a two stage rocket has occurred too low (probably due to a flight problem like a failed air start), you can fire the main parachute immediately instead of waiting for descent.

Continuity: This allows you to put a constraint on the continuity of your used (non PWM) output channels.

Descent Velocity: This allows you to specific a minimum or maximum decent velocity when a given descent altitude is reached.

Continuity: This allows you to put a constraint on the continuity of your used (non PWM) output channels.

Descent Altitude: This allows you to specific a minimum or maximum decent altitude when a given descent velocity is reached.

Continuity: This allows you to put a constraint on the continuity of your used (non PWM) output channels.

A Rule's Action is what to do once the Rule has been triggered.

The possible Actions are:

This turns an output channel on.

• You must specify which Channel to turn on
• The Channel will stay on until the rocket is disarmed or another Action turns it off. Landing does not automatically turn Channels off.
• Another Rule's Action can turn it back off
• If a Channel is already on when the Turn Channel On Action is applied to it, the Channel will remain on, this does not cause a problem.
• This is useful for activating external electronics or trackers

This turns an output channel off.

• You must specify which Channel to turn off
• Another Rule's Action can turn it back on. Landing does not automatically turn a Channel off. If you want this to happen you must create an appropriate Rule.
• If a Channel is already off when the Turn Channel Off Action is applied to it, the Channel will remain off, this does not cause a problem.

This turns a Channel on for a defined period of time, and then turns it off again.

• This is the recommended Action for e-match ignition, typically enabling the Channel for 2000ms is enough to ignite most e-matches, although test this with your chosen brand.
• You must define the On-duration
• If a Channel is already on when the Turn Channel On Then Off Action is applied to it, the Channel will remain on for the On-Duration, but will then be turned off. It will not stay on because it was already on.
• Beware advanced configurations with overlapping two On-Off actions for the same channel in time. For example, if you have an action to turn channel 1 On for 2000ms and then Off and this fires at Apogee, but then you have another On-Off rule to fire at Apogee + 500ms, the on-duration of the second action could be cut short as the first one elapses and turns off.

This will output a PWM signal at the given duty cycle and frequency

• You must provide the Channel and Pulse Width for the Action. The PWM Freqency is controlled under Advanced Settings for the Flight Configuration, meaning all PWM output channels use the same frequency.
• You cannot mix On/Off Actions with PWM Actions for a given channel.

This will turn the beeper on constantly.

This will turn the beeper off.

This will cause the beeper to beep n times and then stop.

This will cause the beeper beep out the maximum altitude achieved in the flight. If the apogee altitude was 802m, it would beep 8 times, pause slightly, beep 10 times (signifying a zero), pause slightly, beep 2 times, pause for a longer time, then repeat ad infinitum.

This will will disarm your rocket. This action can only be used with the Armed trigger and a Condition set. Use this to "prevent" arming under undesired conditions by immediately disarming the rocket when arming is attempted.

The Flight Logs page lets you review the flight data from all previous flights, as well as showing you the total used and remaining flight log space.

Once you have recovered your Grissom after flight, we recommend accessing the Flight Log page as soon as possible with your device in WiFi Station Mode. From the Flight Log page you will be prompted to backup the new flight log to cloud storage where it will be safely stored for ever.

Click the View button next to the Flight Log you wish to view.

From here you can download the flight data as CSV, view the flight telemetery and see a detailed event log of everything that happened (or didnt in the case of Flight Configuration Rules with Conditions) during the flight.

The Flight Details section shows you a summary of the flight information and lets you download the flight data as a CSV.

The Visualisation section shows a graph of your rockets altitude and speed from just before launch to 5 seconds after landing.

You can toggle the visibility of annotations showing the actions taken and the events that occured. Note that actions/events which occurred long before launch (e.g. arming) are not shown on the graph.

Here we can see a simple flight, showing the drogue (Channel 1) being fired at apogee and the main (Channel 2) being fired at 150m.

The continuity bars show when continuity was lost for each channel. This is useful for debugging failed flights when continuity was lost unexpectedly.

The Stats section shows you the key metrics of the flight.

The Configuration section shows you what happened with each Rule during the flight. This can be extremely useful for debugging.

Here we can see that our first four rules were triggered, but our Emergency freefall main rule didn't trigger as we didn't descend fast enough - a good thing in this case.

The event log details everything Grissom either did or tried to do, and the telemetry from that moment in time.

Here we can see the event log from a simple flight with a drogue at apogee and a main at 150m/500ft.

In the event that your Grissom is running low on storage, you can delete previous flight logs. We recommend enabling Cloud Backup before you do this, as your logs can be preserved for ever without worring about local storage issues. When connected to the Internet you can view all previous logs made with your Grissom. Logs which exist only in cloud backup and not on your device will show in the Flight Log list, but do not take up any space on the device.

By default, your Grissom will show it's unique MAC address at the top, allowing you to diffrentiate one Grissom you own from another.

These seemingly random collection of letters and number howwver are not that memorable, and two devices you own may have very similar MAC addresses. If you have two Grissoms in one rocket you might easily get confused as to which is which.

To combat this, you can give your device a nickname which will then show at the top in place of the MAC address.

The Dashboard of your Grissom will show you the voltages of the Deployment Battery and Battery. The accuracy of these measurements depend on accurate resistance reading of electronic components (resistors) on the device itself. See the Power page for a detailed description and explanation of what to do here.

Grissom supports connecting to Shepard which can relay flight telementry and output events to your ground station (Goddard), forwarding all flight information. You can either connect your Grissom and Shepard via UART (see I/O page for details) or have them communicate over Bluetooth. The advantage of Bluetooth is that Shepard can concurrently pair with upto 3 Grissoms where as UART is limited to 1, and you don't need wires, meaning you can physically separate the devices and have them still communicate.

Shepard will automatically discover and connect to enabled Grissoms, provided they share the same PIN number. Choose a random 6 digit PIN and enter this into your Grissom and Shepard.

Note that a Grissom can only connect to one Shepard at a time.

Do not enable the Bluetooth functionality if you won't be using it, as this will put additional, unnecessary load on your battery.

Grissom can integrate directly with UKRA's Members Portal and Flight Logging tool, to enable Grissom's flight log data to be directly attached to a flight in your UKRA Flight Log.

Visit https://members.ukra.org.uk/account/security and generate an API key. Copy and paste it into the Settings page on your Grissom.

Then from the View Flight Log page, use the ⋮ menu to "Upload to UKRA".

Each of the 2 outputs on your Grissom can be controlled independently and are numbered 1 and 2. Outputs need not be used for a predetermined purpose (e.g. Drogue parachute), you can use any channel for any purpose. This can be useful for cable routing, allowing you to use the most convenient terminals for your application.

You should connect your ignitor between then + and - terminals labelled for the output channel, do not share a ground directly with your battery. The -ve terminal of the output is electronically switched as well as the +ve, providing extra safety on the pad.

If you want to use the output to trigger logic on an external device, e.g. turn a radio transmitter on, you should ensure you have a common ground to avoid floating-ground issues.

This feature is still under development, contact your vendor before purchase if you will rely on this feature.

Grissom can drive any of the common 1-wire chainable LED chipsets:

• Neopixel / WS2811 / WS2812(B) / WS2813
• TM1809/4
• TM1803
• UCS1903
• GW6205

Grissom ships with a number of predefined effects.

This calculator is useful for working out the power requirements for your LEDs.

You should ensure the ground pin is shared between your LEDs' power supply and Grissom to avoid floating-ground issues.

The LED output data pin connects directly to the GPIO port of the microcontroller, so take care not to do anything to damage the MCU. There is no series resistor in place which is sometimes useful for anti-ringing and current limiting purposes. This article provides some good insight into the necessity of a series resistor.

The Touch pin is used for waking your Grissom from low-power mode. See the Power page for more information on this.

Grissom exposes a standard UART/Serial port running at 115200 baud.

Connect an FTDI UART (or similar) adaptor at 3.3V to the Gnd, Tx and Rx pins.

Grissom will output a host of information on boot and during use which can be helpful to advanced users when debugging issues.

Grissom can be connected to other Trullock Aerospace devices (e.g. Shepard) in order to relay flight information back to the ground.

This can be achieved in either wired mode, using the UART pins, or wireless mode using Bluetooth. We recommend the latter as there is less chance of wiring failures.

For wired interconnectivity, connect the Tx pin from Shepard to the Rx pin on Grissom, and the Rx pin from Shepard to the Tx pin on Grissom. Connect the Gnd pin from Grissom to the Gnd pin on Shepard.

See the Specifications page for the pinout information.

You can access the firmware update page via the Update button on the Device Info page accessible via the menu.

If you are connected to WiFi via Station mode and a new firmware version is available, you will be given the option to automatically update.

If you are connected to WiFi via Station mode you can rollback to a previous firmware version. You should only need to do this if you are experiencing issues with a newer version. Contact your vendor before going down this route.

You can perform a factory reset from the firmware update page.

This will clear all data from your device and reset all your settings, as well as rolling back to the stock firmware the device shipped with.

If you are unable to connect to your device you can initiate a factory reset by shorting the Factory Reset (Rst) pads on the board. Note that you need to use a good conductor to short the pads, and ensure they are well connected to the pads. If you experience issues here you can try tinning the pads with a little solder to provide a more conductive surface.

Grissom creates its own 2.4GHz WiFi access point which you can connect to using any modern device. You can either set Grissom to use the its default access point SSID, or have it use the device's nickname, or have it be the current active flight configuration. Note that you should choose a memorable password as the last setting will cause the SSID to change.

Grissom will also attemp to connect to upto 3 WiFi access points as a station. When you are not connected to Grissom's access point, it will periodically attempt to connect to each saved access point in order.

Grissom's access point is still available when it is connected as a station to an external access point. However, be aware that Grissom's access point will be briefly unavailable when it attempts to connect to any saved access points.

You should not connect Grissom to any WiFi network that you do not have complete control over. For example, do not connect it to a public WiFi network at a launch site as any other users of the network will be able to control your device, potentially changing the configuration or firing output channels.

Shepard is a GNSS based tracker with an advanced but simple to use interface.

It transmits its location to a ground station (Goddard) over LoRa, as well as forwarding flight data from any connected Gagarin/Grissom devices.

• 2.5m GNSS accuracy
• 915MHz LoRa long range radio
• 1-wire 800kHz digital LED output
• Connects to upto 3 Gagarin/Grissom devices over BLE to relay flight data
• Wake-on-touch low-power functionality
• Over-the-air firmware updates
• UART port for debug and expansion

Once your Shepard is assembled and powered up, it will create a WiFi Access Point which you can connect to with any compatible device.

The WiFi SSID will be of the form Shepard_AABBCCDD, where AABBCCDD is a unique ID for device. The default password is blank, you should change this straight away once connected.

Use the WiFi settings on your phone/laptop to connect to your Shepard's Access Point. After you connect, your phone/laptop will tell you to "Sign In" to the WiFi network. This is a feature of WiFi networks that allows a webpage to be opened immediately after connecting. Usually this is used by public WiFi networks to authenticate you. Here it's used as a convenience so you don't need to remember or type in an IP addresses to get started. If this message doesn't pop up automatically, there should be a Sign In button in your device's WiFi settings page to click.

If your device says something to the effect of "This network does not provide Internet connectivity, do you want to stay connected?" Choose Yes, otherwise you will be disconnected and have to start again.

Some devices' default behaviour is to automatically disconnect you from WiFi networks that do not provide Internet connectivity. If you are struggling with this, disable your cellular Internet.

The first thing you will see on the device's Flight Control page is a warning about insecure WiFi.

Click the Configure Connectivity button to fix this.

Provide a memorable password for the device's Access Point to secure it against unwanted users. If you forget this and can't otherwise connect to your device you'll need to do a Factory Reset.

We strongly advise using your Shepard in Station mode. This means having it connect to another WiFi network such as one hosted by your phone's hotspot. This gives your device the ability to talk to the Internet and as such you get additional features such as centralised control of all Trullock Aerospace devices without having to connect to each device separately.

The access point must be 2.4GHz, if using your phone's hotspot you may need to enable "Enhanced compatability mode" or similarly named feature to activate 2.4GHz mode.

After you save the WiFi settings your phone/laptop will be disconnected. You will either need to reconnect to the device's Access Point using the password you just created, or connect to it via the external WiFi network whos details you provided. To do this:

1. If your connected device supports mDNS (most do) you can visit http://shepard_aabbccdd.local (where aabbccdd are the same as the device's Access Point SSID)
2. If (2) doesn't work or mDNS is not available, you need to connect to your device by it's IP Address. To find this, you have 3 options:
   • Connect to your Shepard's Access Point and goto the Device Info page under the main menu. Here it will tell you the device's Station IP (it can be connected to an access point and BE an access point at the same time). Make a note of this, disconnect from the Shepard's Access Point and reconnect to the same network as the Shepard and then visit that IP Address in your browser.
   • Consult your WiFi's router DHCP table to find the IP it gave your Shepard.
   • Connect a UART adaptor to the Gnd, Rx, Tx pins and observe the Serial output on boot, it will report it's Station IP.

If you are connected to your Shepard in Station Mode, you may see an "Update available" hint.

If you see this, follow the onscreen instruction to update your device to the latest firmware to benefit from bug fixes and new features.

Go to the Settings page and configure LoRa and optionally Bluetooth.

15V is the maximum voltage you should apply to the Battery terminals.

5V is the minimum you should provide to the Battery terminals.

UART runs at 3.3V.

LED-Out is 3.3V. This is a 1-wire data protocol and not a high-current LED power supply.

We recommend a 7.4V (2S LiPo) battery with at least 450mAh capacity.

We do not recommend 9V PPP batteries.

With WiFi running and active connected clients (e.g. your smartphone whilst setting up your device), satellites fixed and Bluetooth enabled and connected the current consumption is approx. 220mA.

Typically flight electronics are enabled at the pad with a physical switch. Gagarin gives you the option to eliminate this point of failure by allowing you to boot the device into low-power mode, and then awaken it at the pad using a capacitive touch input. When in low-power mode current consumption is approx. 9mA.

The Dashboard of your Shepard will show you the voltages of the battery.

You can improve the accuracy of the voltage measurements by providing exact resistances for 2 resistors.

Measure the resistances of R2 and R3 and record their exact resistences preferrably before assembly but after is OK too with the board unpowered.

Hardware version 1.0.x

Once your board is assembled and up and running, navigate to the Settings page and input the measured values. This will provide improved voltage reporting. Be accurate, even a small resistance deviation can produce meaningful measurement differences.

The PCB is 20.2mm × 64.8mm made from 1.6mm FR-4.

The mounting holes are 3mm diameter.

Fully populated, the device weighs approx. 24g.

The brain of Shepard is an ESP32, dual-core, 240MHz, 32bit Xtensa LX6 microprocessor. It is designed to achieve the best power and RF performance, showing robustness, versatility and reliability in a wide variety of applications and power scenarios. It communicates via WiFi 802.11b/g/n in the unlicensed 2.4GHz. To comply with radio licensing laws you should build Shepard exactly as specified and not modify the radio module in any way.

The GNSS module is a Quectel L86 GNSS module with an embedded patch antenna (18.4mm × 18.4mm × 4mm) and LNA brings high performance of MTK positioning engine to the industrial applications. It is able to achieve the industry's highest level of sensitivity, accuracy and TTFF with the lowest power consumption in a small-footprint lead-free package.

The LoRa module is a HopeRF RMF95 which can achieve a sensitivity of over 148dBm using a low cost crystal and bill of materials. The high sensitivity combined with the integrated +20 dBm power amplifier yields industry leading link budget making it optimal for any application requiring range or robustness.

This is the main page of your Shepard and is where you ready it for flight.

In order to fly you'll need/want to:

Ensure your battery is healthy and has a good voltage, you will be warned if its within a low range for LiPos.

Shepard usually takes around 30s from power-on (or wake from low-power mode) to start finding satellites. We recommend allowing a good few minutes to achieve maximum satellite connectivity.

If you have enabled Bluetooth connectivity between a Gagarin/Grissom and Shepard and have set the PINs correctly on all devices, or are using wired UART connectivity after a few seconds of both devices being activated you should see them here.

By default, your Shepard will show it's unique MAC address at the top, allowing you to diffrentiate one device you own from another.

These seemingly random collection of letters and numbers however are not that memorable, and two devices you own may have very similar MAC addresses. If you have two Gagarins in one rocket you might easily get confused as to which is which.

To combat this, you can give your device a nickname which will then show at the top in place of the MAC address.

Shepard communicates to the ground station (Goddard) using LoRa. To avoid interference between other local LoRa communications (e.g. other fliers with LoRa devices) you must set a unique sync-word. This must be the same value on your transmitters and recievers.

Goddard supports receivng data from multiple Shepards, so if your rocket contains two Shepards (e.g. one in a booster and another in the upper stage) it will understand and render the data separately. If you accidentally set the same sync-word as another flier, you will see both devices on Goddard. If you set the same sync-word as a non-Shepard transmitter, the interfering signals could confuse Goddard.

Note that LoRa communication is not encrypted, meaning anyone within range will be able to read the data coming from your Shepard.

Shepard can also act as a relay between Gagarin/Grissom and your ground station (Goddard), forwarding all flight information. You can either connect your Gagarin/Grissom and Shepard via UART (see I/O page for details) or have them communicate over Bluetooth. The advantage of Bluetooth is that Shepard can concurrently pair with upto 3 Gagarin/Grissoms where as UART is limited to 1, and you don't need wires, meaning you can physically separate the devices and have them still communicate.

Shepard will automatically discover and connect to enabled Gagarin/Grissom devices, provided they share the same PIN number. Choose a random 6 digit PIN and enter this into your Gagarin/Grissoms and Shepard.

Note that a Gagarin/Grissom can only connect to one Shepard at a time.

Do not enable the Bluetooth functionality if you won't be using it, as this will put additional, unnecessary load on your battery.

The Dashboard of your Shepard will show you the voltage of the battery. The accuracy of this measurement depends on accurate resistance reading of electronic components (resistors) on the device itself. See the Power page for a detailed description and explanation of what to do here.

To save battery power when preparing your rocket, a common technique is to have a physical switch in series with your battery and flight electronics. This is a point of failure as well as added physical complexity which Shepard avoids.

Enabling low-power mode causes Shepard to power up using minimal battery power. When you are on the pad and ready to fly you can wake up Shepard and have it turn on all its peripheral hardware and begin functioning fully. This feature works using capacitive touch functionality.

Run a wire from the Touch pin to the outside of the airframe on your electronics bay, usually by exposing a screw head on the outside of the airframe and connecting the wire to the inside. Keep the wire as short as possible and ideally away from other metallic (capacitive) items.

Fully assemble your electronics bay as you would for flight, power on your Shepard (and any other devices in your electronics bay).

Visit the settings page for Shepard and observe the Touch Sensor Value bar. Touch your finger on the exposed Touch Pin (screw head) and observe the change in the Touch Sensor Value. Repeat this a few times to get a good feel for what the finger-on vs finger-off values look like. Set the Detection Threshold slider to somewhere in bettwen the finger-on and finger-off values to calibrate the touch detector.

The next time you power on your Shepard it will boot into Low-Power mode and beep 3 times to indicate a low-power boot. To wake it, you must touch the Touch pin (in the same manner as you did during calibration).

See the Power page for details on current consumption.

Shepard can drive any of the common 1-wire chainable LED chipsets:

• Neopixel / WS2811 / WS2812(B) / WS2813
• TM1809/4
• TM1803
• UCS1903
• GW6205

Shepard ships with a number of predefined effects which can be controlled from the Flight Control page.

This calculator is useful for working out the power requirements for your LEDs.

You should ensure the ground pin is shared between your LEDs' power supply and Shepard to avoid floating-ground issues.

The LED output data pin connects directly to the GPIO port of the microcontroller, so take care not to do anything to damage the MCU. There is no series resistor in place which is sometimes useful for anti-ringing and current limiting purposes. This article provides some good insight into the necessity of a series resistor.

See the Specifications page for the pinout information.

The Touch pin is used for waking your Shepard from low-power mode. See the Power page for more information on low power mode and see the Specifications page for pinout information.

Note that the Touch pin is also the UART Programming pin, and must not be grounded when you power on your Shepard else it will not boot correctly.

Shepard exposes a standard UART/Serial port running at 115200 baud.

Connect an FTDI UART (or similar) adaptor at 3.3V to the Gnd, Tx and Rx pins.

Shepard will output a host of information on boot and during use which can be helpful to advanced users when debugging issues.

Shepard can be connected to other Trullock Aerospace devices (e.g. Gagarin, Grissom) in order to relay flight information back to the ground.

This can be achieved in either wired mode, using the UART pins, or wireless mode using Bluetooth. We recommend the latter as there is less chance of wiring failures.

For wired interconnectivity, connect the Tx pin from Gagarin/Grissom to the Rx pin on Shepard, and the Rx pin from Gagarin/Grissom to the Tx pin on Shepard. Connect the Gnd pin from Gagarin/Grissom to the Gnd pin on Shepard.

See the Specifications page for the pinout information.

You can access the Firmware Update page via the Update button on the Device Info page accessible via the menu.

If you are connected to WiFi via Station mode and a new firmware version is available, you will be given the option to automatically update.

If you are connected to WiFi via Station mode you can rollback to a previous firmware version. You should only need to do this if you are experiencing issues with a newer version. Contact your vendor before going down this route.

You can perform a factory reset from the firmware update page.

This will clear all data from your device and reset all your settings, as well as rolling back to the stock firmware the device shipped with.

If you are unable to connect to your device you can initiate a factory reset by shorting the Factory Reset (Rst) pads on the board. Note that you need to use a good conductor to short the pads, and ensure they are well connected to the pads. If you experience issues here you can try tinning the pads with a little solder to provide a more conductive surface.

See the Specifications page for the pinout information.

Shepard creates its own 2.4GHz WiFi access point which you can connect to using any modern device.

Shepard will also attemp to connect to upto 3 WiFi access points as a station. When you are not connected to Shepard's access point, it will periodically attempt to connect to each saved access point in order.

Shepard's access point is still available when it is connected as a station to an external access point. However, be aware that Shepard's access point will be briefly unavailable when it attempts to connect to any saved access points.

You should not connect Shepard to any WiFi network that you do not have complete control over. For example, do not connect it to a public WiFi network at a launch site as any other users of the network will be able to control your device, potentially changing the configuration or firing output channels.

Goddard is the ground station companion to the Shepard tracker.

It receives location data from Shepard devices over LoRa, as well as flight data from any connected Gagarin/Grissom devices.

• Renders location and flight event information directly to your smartphone or laptop
• Receives data from unlimited Shepard devices
• Over-the-air firmware updates

Once your Goddard is assembled and powered up, it will create a WiFi Access Point which you can connect to with any compatible device.

The WiFi SSID will be of the form Goddard_AABBCCDD, where AABBCCDD is a unique ID for device. The default password is blank, you should change this straight away once connected.

Use the WiFi settings on your phone/laptop to connect to your Goddard's Access Point. After you connect, your phone/laptop will tell you to "Sign In" to the WiFi network. This is a feature of WiFi networks that allows a webpage to be opened immediately after connecting. Usually this is used by public WiFi networks to authenticate you. Here it's used as a convenience so you don't need to remember or type in an IP addresses to get started. If this message doesn't pop up automatically, there should be a Sign In button in your device's WiFi settings page to click.

If your device says something to the effect of "This network does not provide Internet connectivity, do you want to stay connected?" Choose Yes, otherwise you will be disconnected and have to start again.

Some devices' default behaviour is to automatically disconnect you from WiFi networks that do not provide Internet connectivity. If you are struggling with this, disable your cellular Internet.

The first thing you will see on the device's Flight Control page is a warning about insecure WiFi.

Click the Configure Connectivity button to fix this.

Provide a memorable password for the device's Access Point to secure it against unwanted users. If you forget this and can't otherwise connect to your device you'll need to do a Factory Reset.

We strongly advise using your Goddard in Station mode. This means having it connect to another WiFi network such as one hosted by your phone's hotspot. This gives your device the ability to talk to the Internet and as such you get additional features such as centralised control of all Trullock Aerospace devices without having to connect to each device separately.

The access point must be 2.4GHz, if using your phone's hotspot you may need to enable "Enhanced compatability mode" or similarly named feature to activate 2.4GHz mode.

After you save the WiFi settings your phone/laptop will be disconnected. You will either need to reconnect to the device's Access Point using the password you just created, or connect to it via the external WiFi network whos details you provided. To do this:

1. If your connected device supports mDNS (most do) you can visit http://goddard_aabbccdd.local (where aabbccdd are the same as the device's Access Point SSID)
2. If (2) doesn't work or mDNS is not available, you need to connect to your device by it's IP Address. To find this, you have 3 options:
   • Connect to your Goddard's Access Point and goto the Device Info page under the main menu. Here it will tell you the device's Station IP (it can be connected to an access point and BE an access point at the same time). Make a note of this, disconnect from the Goddard's Access Point and reconnect to the same network as the Goddard and then visit that IP Address in your browser.
   • Consult your WiFi's router DHCP table to find the IP it gave your Goddard.
   • Connect a UART adaptor to the Gnd, Rx, Tx pins and observe the Serial output on boot, it will report it's Station IP.

If you are connected to your Goddard in Station Mode, you may see an "Update available" hint.

If you see this, follow the onscreen instruction to update your device to the latest firmware to benefit from bug fixes and new features.

Go to the Settings page and configure LoRa.

15V is the maximum voltage you should apply to the Battery terminals.

5V is the minimum you should provide to the Battery terminals.

UART runs at 3.3V.

We recommend a 7.4V (2S LiPo) battery with at least 450mAh capacity. If you're going to be doing multiple flights all day, the bigger the better.

We do not recommend 9V PPP batteries.

With WiFi running and active connected clients (e.g. your smartphone whilst setting up your device) and satellites fixed the current consumption is approx. 220mA.

The Dashboard of your Goddard will show you the voltages of the battery.

You can improve the accuracy of the voltage measurements by providing exact resistances for 2 resistors.

Measure the resistances of R2 and R3 and record their exact resistences preferrably before assembly but after is OK too with the board unpowered.

Hardware version 1.0.x

Once your board is assembled and up and running, navigate to the Settings page and input the measured values. This will provide improved voltage reporting. Be accurate, even a small resistance deviation can produce meaningful measurement differences.

The PCB is XXmm × YYmm made from 1.6mm FR-4.

The mounting holes are 3mm diameter.

Fully populated, the device weighs approx. ZZg.

The brain of Goddard is an ESP32, dual-core, 240MHz, 32bit Xtensa LX6 microprocessor. It is designed to achieve the best power and RF performance, showing robustness, versatility and reliability in a wide variety of applications and power scenarios. It communicates via WiFi 802.11b/g/n in the unlicensed 2.4GHz. To comply with radio licensing laws you should build Goddard exactly as specified and not modify the radio module in any way.

The GNSS module is a Quectel L86 GNSS module with an embedded patch antenna (18.4mm × 18.4mm × 4mm) and LNA brings high performance of MTK positioning engine to the industrial applications. It is able to achieve the industry's highest level of sensitivity, accuracy and TTFF with the lowest power consumption in a small-footprint lead-free package.

The LoRa module is a HopeRF RMF95 which can achieve a sensitivity of over 148dBm using a low cost crystal and bill of materials. The high sensitivity combined with the integrated +20 dBm power amplifier yields industry leading link budget making it optimal for any application requiring range or robustness.

This is the main page of your Goddard and is where you ready it for flight.

In order to fly you'll need/want to:

Ensure your battery is healthy and has a good voltage, you will be warned if its within a low range for LiPos.

Goddard usually takes around 30s from power-on (or wake from low-power mode) to start finding satellites. We recommend allowing a good few minutes to achieve maximum satellite connectivity.

TODO

By default, your Goddard will show it's unique MAC address at the top, allowing you to diffrentiate one device you own from another.

These seemingly random collection of letters and numbers however are not that memorable, and two devices you own may have very similar MAC addresses. If you have two Gagarins in one rocket you might easily get confused as to which is which.

To combat this, you can give your device a nickname which will then show at the top in place of the MAC address.

Goddard communicates to the ground station (Goddard) using LoRa. To avoid interference between other local LoRa communications (e.g. other fliers with LoRa devices) you must set a unique sync-word. This must be the same value on your transmitters and recievers.

Goddard supports receivng data from multiple Goddards, so if your rocket contains two Goddards (e.g. one in a booster and another in the upper stage) it will understand and render the data separately. If you accidentally set the same sync-word as another flier, you will see both devices on Goddard. If you set the same sync-word as a non-Goddard transmitter, the interfering signals could confuse Goddard.

Note that LoRa communication is not encrypted, meaning anyone within range will be able to read the data any of your devices are transmitting.

Goddard can also act as a relay between Gagarin/Grissom and your ground station (Goddard), forwarding all flight information. You can either connect your Gagarin/Grissom and Goddard via UART (see I/O page for details) or have them communicate over Bluetooth. The advantage of Bluetooth is that Goddard can concurrently pair with upto 3 Gagarin/Grissoms where as UART is limited to 1, and you don't need wires, meaning you can physically separate the devices and have them still communicate.

Goddard will automatically discover and connect to enabled Gagarin/Grissom devices, provided they share the same PIN number. Choose a random 6 digit PIN and enter this into your Gagarin/Grissoms and Goddard.

Note that a Gagarin/Grissom can only connect to one Goddard at a time.

Do not enable the Bluetooth functionality if you won't be using it, as this will put additional, unnecessary load on your battery.

The Dashboard of your Goddard will show you the voltage of the Battery. The accuracy of these measurements depend on accurate resistance reading of electronic components (resistors) on the device itself. See the Power page for a detailed description and explanation of what to do here.

Goddard can drive any of the common 1-wire chainable LED chipsets:

• Neopixel / WS2811 / WS2812(B) / WS2813
• TM1809/4
• TM1803
• UCS1903
• GW6205

Goddard ships with a number of predefined effects which can be controlled from the Flight Control page.

This calculator is useful for working out the power requirements for your LEDs.

You should ensure the ground pin is shared between your LEDs' power supply and Goddard to avoid floating-ground issues.

The LED output data pin connects directly to the GPIO port of the microcontroller, so take care not to do anything to damage the MCU. There is no series resistor in place which is sometimes useful for anti-ringing and current limiting purposes. This article provides some good insight into the necessity of a series resistor.

See the Specifications page for the pinout information.

The Touch pin is used for waking your Goddard from low-power mode. See the Power page for more information on low power mode and see the Specifications page for pinout information.

Note that the Touch pin is also the UART Programming pin, and must not be grounded when you power on your Goddard else it will not boot correctly.

Goddard exposes a standard UART/Serial port running at 115200 baud.

Connect an FTDI UART (or similar) adaptor at 3.3V to the Gnd, Tx and Rx pins.

Goddard will output a host of information on boot and during use which can be helpful to advanced users when debugging issues.

Goddard can be connected to other Trullock Aerospace devices (e.g. Gagarin, Grissom) in order to relay flight information back to the ground.

This can be achieved in either wired mode, using the UART pins, or wireless mode using Bluetooth. We recommend the latter as there is less chance of wiring failures.

For wired interconnectivity, connect the Tx pin from Gagarin/Grissom to the Rx pin on Goddard, and the Rx pin from Gagarin/Grissom to the Tx pin on Goddard. Connect the Gnd pin from Gagarin/Grissom to the Gnd pin on Goddard.

See the Specifications page for the pinout information.

You can access the Firmware Update page via the Update button on the Device Info page accessible via the menu.

If you are connected to WiFi via Station mode and a new firmware version is available, you will be given the option to automatically update.

If you are connected to WiFi via Station mode you can rollback to a previous firmware version. You should only need to do this if you are experiencing issues with a newer version. Contact your vendor before going down this route.

You can perform a factory reset from the firmware update page.

This will clear all data from your device and reset all your settings, as well as rolling back to the stock firmware the device shipped with.

If you are unable to connect to your device you can initiate a factory reset by shorting the Factory Reset (Rst) pads on the board. Note that you need to use a good conductor to short the pads, and ensure they are well connected to the pads. If you experience issues here you can try tinning the pads with a little solder to provide a more conductive surface.

See the Specifications page for the pinout information.

Goddard creates its own 2.4GHz WiFi access point which you can connect to using any modern device.

Goddard will also attemp to connect to upto 3 WiFi access points as a station. When you are not connected to Goddard's access point, it will periodically attempt to connect to each saved access point in order.

Goddard's access point is still available when it is connected as a station to an external access point. However, be aware that Goddard's access point will be briefly unavailable when it attempts to connect to any saved access points.

You should not connect Goddard to any WiFi network that you do not have complete control over. For example, do not connect it to a public WiFi network at a launch site as any other users of the network will be able to control your device, potentially changing the configuration or firing output channels.