Project 03 · Rocket avionics

Custom ESP32 Flight Computer

A custom avionics board that reads pressure, temperature, and acceleration, detects flight events like apogee, and fires the parachute deployment circuits.

Period: June 2025 — Jan 2026
Role: Independent engineering project
Tools: KiCadESP32I²CPCB designSMD soldering

Sensors: 3 on I²C
Deployment: N-ch MOSFETs
Fab: JLCPCB
Status: Flown

§ 01

What it does

I designed this board in KiCad around an ESP32, with an MPL3115A2 barometric altimeter, an ADXL345 accelerometer, and an MCP9808 temperature sensor all sharing one I²C bus.

The firmware watches the sensor readings to work out where the rocket is in its flight, including the moment it reaches apogee, and then switches the parachute deployment circuits through N-channel MOSFETs. The recovery logic is configurable, so the same board can be set up for different rockets and deployment plans.

Fig. 03.01Latest revision, fully populated

Fig. 03.02Close-up of the power stage: LM2596 regulator and inductor

§ 02

Iterating on hardware

Each revision was fabricated through JLCPCB and hand-assembled by me, both surface-mount and through-hole parts. Early boards needed bodge wires and rework, and every fix got rolled into the next layout.

Throughout the process I worked with Pieter, an electrical engineer based in Sweden, who reviewed the designs and gave feedback I folded into each new iteration.

Fig. 03.03An earlier revision with rework wires and a flagged capacitor

Fig. 03.04Bench testing with a USB-serial adapter and scope probes

Fig. 03.05Probing the ESP32 module during bring-up

§ 03

Result

The board passed bench testing and was integrated into a rocket.

Next project · 04

Space Enterprise Berkeley