Impulse 1.0
Baseline Architecture
Teensy 4.1 with MPU6050/BMP280 and initial pyro circuitry; pyro path was non-functional.
Sisyphus — Subsystem
Flight Computer
Impulse 2.0 is the custom Sisyphus avionics board for flight sensing, actuator control, pyro events, and telemetry. This layout groups hardware photos, CAD, and specifications into one place for faster understanding.
PCB Specs
- Microcontroller: Teensy 4.1
- Barometer: DPS310
- IMU: BNO-055
- Pyro outputs: 4 channels at 7.4V, each with a continuity-check LED circuit
- Control outputs: 2 servo outputs
- Status and alerts: onboard buzzer and RGB LED
- Power system: two 7.4V LiPo batteries, one dedicated to pyros and one for all other electronics to isolate the circuits and avoid pyro-induced brownouts
PCB History
Development & Iterations
Scroll left to right
The flight computer went through several major hardware revisions. Each iteration solved problems revealed by the last, from basic pyro failures to full SMD layout and trace-width discovery.
Impulse 1.1-1.3
Output Expansion
Expanded servo outputs and switched to larger MOSFETs, but pyro reliability remained unresolved.
Impulse 1.4
Power Isolation
Added dedicated LiPo circuit for pyros to isolate high-current firing from core avionics.
Impulse 2.0
SMD Jump
Attempted ESP32-S2 full-SMD board and adopted BNO055 plus DPS310 sensor stack for future revisions.
Impulse 2.1
Teensy Return
Mostly-SMD layout with Teensy 4.1, continuity checks, and dedicated sensor power; pyro troubleshooting intensified.
Test Boards
Root-Cause Hunt
Isolated pyro and regulator boards exposed trace-width as the pyro ignition bottleneck.
Impulse 2.2
Pyro Success
Widened pyro traces enabled reliable firing and powered the first successful Sisyphus launch.
Impulse 2.3
Density Upgrade
Swapped to smaller SMD MOSFETs while preserving wide pyro routing for robust ignition.