DEEED

DEEED Open-Source Flight Computer

The DEEED Flight Computer is an easy-to-build, open-source flight computer / altimeter for model rockets. It is designed around commonly available breakout boards, so it is simple to assemble and use. I designed it as a good first PCB project for myself and for every hobbyist.

The programming side of the project was mostly done by Claude AI, as I can't really program myself – this accelerated that part enormously. I recommend you write your own code or improve the existing code and design if you can or want to. I hope you have a great experience!

⚠️ Safety notice This is a hobby project, provided without any warranty (see LICENSE). It is not a certified recovery system. In the original setup the ejection charge is fired by the rocket motor itself; the igniter output is an additional function. Follow the laws and safety codes of your rocketry association, and always test the igniter output without any igniter connected.

I Build my own fully custom and 3D printed model Rocket around this Flightcomputer. The Rocket can be found on Makerworld. I also uploaded some of my Flight on YouTube ELG_Space https://www.youtube.com/@ELG_Space

Technical overview

The board is 24 mm wide and 106 mm tall, so it fits into a 35mm airframe.

Pinout

Recommended for each MOSFET: 330 Ω in series with the gate and a 10 kΩ pulldown from gate to GND, so the output can never switch while the MCU is booting.

Code overview

The current software is DEEEDSoft V0.2. It can:

• detect the flight phases automatically: PAD → BOOST → COAST → APOGEE → DESCENT → LANDED
• detect apogee using a median-filtered barometric altitude, a vertical-speed window, a plausibility check and a 15 s backup timer
• fire the igniter output at apogee
• record flight data into RAM during the flight (2000 records, 3 s pre-launch buffer; 50 Hz up to apogee, 5 Hz during descent) and write it after landing to the SD card as flightNNN.csv plus a summary flightNNN.txt
• help you find the rocket: buzzer and a Bluetooth beacon named "Rocket-Recovery" after landing
• show its status on the board's RGB LED (green = IMU, barometer and SD OK; red = something is missing)
• keep running if the barometer misbehaves: it uses its own software I2C with timeouts, powers the BMP280 from D6 and automatically power-cycles it after repeated read errors; a hardware watchdog covers everything else

Serial commands (115200 baud)

Ground test

Pull D0 briefly to GND to step to the next state (PAD → BOOST → … → LANDED). Do this without any igniter connected.

Build and flash

Requires PlatformIO.

Repository layout

The firmware lives in Software/DEEEDSoft 0.2/. Open that folder in VS Code / PlatformIO to build and flash it.

src/main.cpp           main loop, serial console, setup
lib/Sensors/           IMU, BMP280, software I2C
lib/StateMachine/      flight phases and detection logic
lib/Actuators/         igniter and buzzer
lib/DataLogger/        RAM buffer, CSV and summary files on SD
hardware/              KiCad project (schematic and PCB)

All detection thresholds are named constants at the top of lib/StateMachine/StateMachine.cpp.

Known limitations

• Tuned for small model rockets and tested on only a few flights.
• Barometric altitude can be disturbed by airflow or ejection pressure; hence the plausibility check and the backup timer.
• During a BMP280 outage the last valid altitude is held.

Contributing

Issues and pull requests are welcome – especially flight data and improvements to the apogee detection.

License

GPL-3.0