ARK Flow

ARK Flow is an open source DroneCAN optical flow, distance sensor, and IMU module.

Hardware Specifications

• Open Source Schematic and BOM

• Sensors

  • PixArt PAW3902 Optical Flow Sensor

    • Tracks under super low light condition of >9 lux

    • Wide working range from 80mm up to 30m

    • Up to 7.4 rad/s

  • 40mW IR LED built onto board for improved low light operation

  • Broadcom AFBR-S50LV85D Time-of-Flight Distance Sensor

    • Integrated 850 nm laser light source

    • Field-of-View (FoV) of 12.4° x 6.2° with 32 pixels

    • Typical distance range up to 30m

    • Operation of up to 200k Lux ambient light

    • Works well on all surface conditions

    • Transmitter beam of 2° x 2° to illuminate between 1 and 3 pixels

  • Bosch BMI088 6-Axis IMU or Invensense ICM-42688-P 6-Axis IMU

• STM32F412CEU6 MCU

• Two Pixhawk Standard CAN Connectors (4 Pin JST GH)

• Pixhawk Standard Debug Connector (6 Pin JST SH)

• Software-toggleable built in CAN termination resistor

• Small Form Factor

  • 3cm x 3cm x 1.4cm

• LED Indicators

• USA Built

LED Meanings

You will see both red and blue LEDs on the ARK Flow when it is being flashed, and a solid blue LED if it is running properly.

If you see a solid red LED there is an error and you should check the following:

• Make sure the flight controller has an SD card installed.

• Make sure the Ark Flow has ark_can-flow_canbootloader installed prior to flashing ark_can-flow_default.

• Remove binaries from the root and ufw directories of the SD card and try to build and flash again.

Video

Video

PX4 holding position using the ARK Flow sensor for velocity estimation (in Position Mode).

Pinout

CAN - 4 Pin JST-GH

Pin Number	Signal Name	Voltage
1	5V	5.0V
2	CAN_P	5.0V
3	CAN_N	5.0V
4	GND	GND

CAN - 4 Pin JST-GH

Pin Number	Signal Name	Voltage
1	5V	5.0V
2	CAN_P	5.0V
3	CAN_N	5.0V
4	GND	GND

Debug - 6 Pin JST-SH

Pin Number	Signal Name	Voltage
1	3.3V	3.3V
2	USART2_TX	3.3V
3	USART2_RX	3.3V
4	FMU_SWDIO	3.3V
5	FMU_SWCLK	3.3V
6	GND	GND

Firmware

395KB

80-1.16.3c45b562.uavcan.bin

Open

ARK Flow Firmware

9KB

ark_can-flow_canbootloader.bin

Open

ARK Flow Bootloader

Release Notes

• 80-1.16.3c45b562 - 2025-9-26

  • Migrate to build server

• 80-1.16.afb2c08b - 2025-8-6

  • AFBRS50: Fix long range measurement publishing

• 80-1.16.2248a40e - 2025-7-10

  • AFBRS40: fix Range Mode switching

• 80-1.16.d0bfa548 - 2025-6-12

  • AFBRS50 fix scheduling and refactor

• 80-1.15.82ff8744 - 2025-6-11

  • Add DroneCAN RawIMU publisher

• 80-1.16.61036f77 - 2025-2-7

  • Update to AFBR 1.6.5 API

    • Improved distance sensor performance