> For the complete documentation index, see [llms.txt](https://docs.arkelectron.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.arkelectron.com/products/sensor/ark-flow/hardware.md). # Hardware Reference ## Specifications | Specification | Value | | ------------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | | Optical flow sensor | [PixArt PAW3902](https://www.pixart.com/products-detail/93/PAW3902JF-TXQT) | | Flow working range | 80 mm to infinity | | Low light | Tracks under super low light conditions of >9 lux. 40 mW IR LED on the board for improved low light operation | | Max flow rate | 7.4 rad/s | | Distance sensor | [Broadcom AFBR-S50LV85D](https://www.broadcom.com/products/optical-sensors/time-of-flight-3d-sensors/afbr-s50lv85d) time-of-flight, integrated 850 nm laser light source | | Distance range | Typically up to 30 m | | Field of view | 12.4° × 6.2° with 32 pixels. 2° × 2° transmitter beam illuminates 1 to 3 pixels | | IMU | [Bosch BMI088](https://www.bosch-sensortec.com/products/motion-sensors/imus/bmi088/) or [InvenSense ICM-42688-P](https://invensense.tdk.com/products/motion-tracking/6-axis/icm-42688-p/), 6-axis | | MCU | STM32F412CEU6 | | CAN | 2× Pixhawk-standard 4-pin JST-GH, software-toggleable built-in termination resistor | | Debug | Pixhawk-standard 6-pin JST-SH | | Power | 5 V, 71 mA average, 76 mA max | | Dimensions | 3 × 3 × 1.4 cm | | Weight | 5 g | ## Pinout ### CAN (×2) — 4-pin JST-GH | Pin | Signal | Voltage | | --- | ------ | ------- | | 1 | 5V | 5.0 V | | 2 | CAN\_P | 5.0 V | | 3 | CAN\_N | 5.0 V | | 4 | GND | GND | ### Debug — 6-pin JST-SH | Pin | Signal | Voltage | | --- | ---------- | ------- | | 1 | 3.3V | 3.3 V | | 2 | USART2\_TX | 3.3 V | | 3 | USART2\_RX | 3.3 V | | 4 | FMU\_SWDIO | 3.3 V | | 5 | FMU\_SWCLK | 3.3 V | | 6 | GND | GND | ## LEDs 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. ## Wiring The ARK Flow is connected to the CAN bus using a Pixhawk standard 4 pin JST GH cable. For more information, refer to the [CAN Wiring](https://docs.px4.io/main/en/can/#wiring) instructions. Multiple sensors can be connected by plugging additional sensors into the ARK Flow's second CAN connector. ## Mounting The recommended mounting orientation is with the connectors on the board pointing towards **back of vehicle**, as shown in the following picture. ![ARK Flow align with Pixhawk](https://docs.px4.io/main/assets/ark_flow_orientation.auMVvxJ0.png) ## 3D Model and Case | File | Contents | | ------------------------------------------------------------------------------------------------------------------------------------------------------------- | ------------------------------------------- | | [ARK\_Flow\_Rev\_2\_3D\_Model.step](https://github.com/ARK-Electronics/ark-hardware/raw/main/ARK_Flow/model/ARK_Flow_Rev_2_3D_Model.step) | Board, rev 2 | | [ARK\_Flow\_Rev\_2\_3D\_Model\_With\_FOV.step](https://github.com/ARK-Electronics/ark-hardware/raw/main/ARK_Flow/model/ARK_Flow_Rev_2_3D_Model_With_FOV.step) | Board, rev 2, with the sensor field of view | | [Top\_Case\_Rev\_1.stl](https://github.com/ARK-Electronics/ark-hardware/raw/main/ARK_Flow/case/Top_Case_Rev_1.stl) | Case top, rev 1 | | [Bottom\_Case\_Rev\_1.stl](https://github.com/ARK-Electronics/ark-hardware/raw/main/ARK_Flow/case/Bottom_Case_Rev_1.stl) | Case bottom, rev 1 | All files: [ARK\_Flow in ark-hardware](https://github.com/ARK-Electronics/ark-hardware/tree/main/ARK_Flow) ## Schematic and BOM | File | Contents | | -------------------------------------------------------------------------------------------------------------------------------------------- | ------------------------ | | [ARK\_Flow\_Rev\_2\_Schematic.pdf](https://github.com/ARK-Electronics/ark-hardware/raw/main/ARK_Flow/schematic/ARK_Flow_Rev_2_Schematic.pdf) | Schematic, rev 2 | | [ARK\_Flow\_Rev\_2\_BOM.xlsx](https://github.com/ARK-Electronics/ark-hardware/raw/main/ARK_Flow/bom/ARK_Flow_Rev_2_BOM.xlsx) | Bill of materials, rev 2 | --- # Agent Instructions This documentation is published with GitBook. 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