Model Rocket & ESP32 Flight Computer

The Build

• Built the flight computer from discrete parts on soldered perfboard instead of buying an off-the-shelf altimeter — ESP32-S3, BME280 barometer on I²C, TPS61023 boost converter for the rail
• Firmware averages ten pressure samples on boot for a ground baseline, then logs time, pressure, temperature, and derived altitude at 20 Hz with the pressure reading oversampled 16×
• Each power cycle opens a new flight_N.csv, flushed to flash every second, so an unexpected power loss costs at most one second of data and never overwrites an earlier flight
• Serial console at 115200 baud lists stored logs, dumps them for retrieval, erases flash, and pauses capture
• Fin can, nose cone, and launch-rail clamp modeled in SOLIDWORKS and 3D printed; recovery is a parachute deployed by the motor's ejection charge
• Launched on a hand-built nichrome igniter fired from a 9 V controller with a two-stage interlock — an arming switch in series with a momentary button, so no single press can energize the igniter

Measured vs. Predicted

The OpenRocket model was built before the flight. 401 samples came back off the flash afterward.

• Apogee and timing landed within a fraction of a percent. The velocity gap is expected — there is no accelerometer on board, so climb rate is finite-differenced from barometric altitude, which lags during the two-second burn and smooths the true peak
• Ground samples before launch and after landing spread ±0.2 m, which is the practical altitude resolution of the BME280 here — small enough to resolve a 119 m apogee to better than 0.2%
• Descent under parachute settled at 7.6 m/s