CXOF (also known as Holybro Optical Flow Module) is a production-ready optical-flow module built around the PMW3901 chip. Designed for direct ArduPilot integration over UART, no driver development needed.
Spec card
| Spec | Value |
|---|---|
| Underlying chip | PixArt PMW3901 |
| Range (altitude) | 8 cm – 4 m typical indoor |
| Interface | UART 19200 baud, ArduPilot protocol |
| ArduPilot setup | FLOW_TYPE = 6 |
| Power | 5 V, ~50 mA |
| Weight | ~10 g |
| Connector | 4-pin GH (VCC, GND, TX, RX) |
Why CXOF over raw PMW3901
- No driver work — ArduPilot already supports the protocol.
- Properly tested — Holybro publishes calibration data.
- 5× more expensive (~$50 vs ~$10 for raw chip) but the time saved is worth it for most users.
Where to go next
- Setup — ArduPilot wiring recipe
- Limits — when CXOF works and doesn’t
- PMW3901 limits — same chip, same physical constraints