Holybro PMW3901 Optical Flow Sensor
by Holybro

The Holybro PMW3901 Optical Flow Sensor (SKU: 19005) is an ultra-compact, UART-based downward-facing optical flow module engineered to enable precise horizontal position hold and drift-free velocity estimation in GPS-denied environments. Built around the PixArt PMW3901 optical tracking sensor with an integrated onboard BEC, this module allows autonomous drones and robotic platforms to maintain stable indoor hover, warehouse navigation, and low-altitude precision landings where satellite GNSS signals are unavailable or unreliable.

Designed for rapid integration with Pixhawk-standard autopilots, the sensor comes factory pre-soldered with a 170mm 6-pin JST-GH latching cable that plugs directly into the TELEM port of most flight controllers. Measuring just 14 x 11 x 5 mm and weighing 0.6 grams, the module outputs X/Y motion vectors and surface quality metrics at 95Hz over a 19200-baud UART connection. It supports both PX4 and ArduPilot firmware (utilizing the standard 9-byte CX-OF serial data protocol) and ships with a custom-molded TPU protective shell for durable airframe mounting.

Key Features

• GPS-Denied Position Stabilization: Tracks ground surface texture and X/Y translational movement from 80mm upward, preventing horizontal drift indoors, under canopies, or in urban canyons.

• Plug-and-Play 6-Pin JST-GH Interface: Arrives pre-soldered with a 170mm 6-pin JST-GH 1.25mm cable wired for direct connection to standard Pixhawk TELEM ports.

• Integrated Onboard BEC: Built-in voltage regulation accepts 3.3V to 5.2V DC input directly from flight controller telemetry rails while consuming only 10mA of current.

• PX4 & ArduPilot Native Compatibility: Fully supported in PX4 EKF2 optical flow estimation and natively compatible with ArduPilot via the 9-byte CX-OF serial protocol.

• Ultralight 0.6g Micro Footprint: Compact 14 x 11 x 5 mm PCB design adds negligible mass, making it ideal for micro autonomous quadcopters, indoor inspection rigs, and research UAVs.

• Included TPU Protective Case: Ships with a flexible, form-fitting TPU shell that shields delicate surface-mount electronics during mounting and operation.

Technical Specifications

• Brand / Manufacturer: Holybro

• Model Identifier: PMW3901 Optical Flow Sensor

• Manufacturer SKU / Part Number: 19005

• Optical Sensing Element: PixArt PMW3901

• Communication Interface: UART (Serial TTL)

• Baud Rate: 19200 bps

• Frame Rate / Update Rate: 95 Hz

• Field of View (FoV): 42°

• Working Distance Range: ~80 mm to infinity (requires adequate ambient lighting and surface texture)

• Max Motion Detection Speed: 7.4 rad/s

• Serial Data Format: 9-Byte Packet (0xFE Header, 0x04 Length, X-Motion High/Low, Y-Motion High/Low, Checksum, Surface Quality, 0xAA Footer)

• Input Voltage Range: 3.3V – 5.2V DC (Integrated onboard BEC; sensor core 2.0V–3.6V)

• Current Consumption: 10 mA

• Connector Type: Pre-installed 6-Pin JST-GH 1.25mm Latching Connector (170 mm cable length)

• Firmware Compatibility: PX4 Autopilot, ArduPilot (CX-OF Optical Flow Protocol)

• Dimensions: 14 mm x 11 mm x 5 mm

• Net Weight: 0.6 grams (sensor PCB only)

• Enclosure: Included Molded TPU Protective Shell

What Is Included

• (1) Holybro PMW3901 Optical Flow Sensor Module (SKU: 19005)

• (1) Pre-Installed 6-Pin JST-GH 1.25mm Cable (170 mm)

• (1) TPU Protective Case Shell