Specifications: 168 MHz Cortex M4F CPU (128 + 64 KB RAM) 752×480 MT9V034 image sensor, L3GD20 3D Gyro 16 mm M12 lens (IR block f
MT9V034 machine vision CMOS sensor with global shutter
Optical flow processing at 4×4 binned image at 120 (indoor) to 250 Hz (outdoor)
Superior light sensitivity with 24×24 μm super-pixels
Onboard 16bit gyroscope up to 2000°/s and 780 Hz update rate, default high precision-mode at 500°/s
Onboard sonar input and mount for Maxbotix sonar sensors. PX4 Flow comes with the sonar already mounted and installed. MB1043
USB serial up to 921600 baud (including live camera view with QGroundControl)
USB power option
In order to use QgroundControl, PX4Flow and ArduPilot, you will need to complete setup and focussing with the firmware loaded by QGroundControl, and then update the firmware to be compatible with ArduPilot.
Select the Vehicle Setup page, and click the Firmware tab.
Connect the PX4Flow sensor to your computer using a micro USB cable.
Check the “Standard Version (stable)” is selected in the right hand pane. Click “OK”. QGroundControl will flash a firmware that can be used to focus the lens.
Unplug and replug the sensor. Two extra tabs should appear: “PX4Flow” and “Parameters”.
Click “PX4Flow”, remove the lens cap and point the camera at a high contrast object at least 3m away. Remove the small screw that stops the lens from turning and adjust the focus until the image appears clearly. This will focus the device to infinity. Refit the screw.
Download and unzip the
Unplug the sensor, click on the “Firmware” tab and replug the sensor.
On the right hand side, click on the firmware version dropdown, and select “Custom firmware file”. Click “OK”. Then select the firmware downloaded above. QGroundControl should now flash a firmware compatible with ArduPilot. QGroundControl will now think that the sensor is a Pixhawk. Dont worry. Unplug it, and connect it to your autopilot.
Connect to the Pixhawk
The sensor should be connected to the autopilot via the 4-pin I2C port. In most cases an I2C splitter should be used to allow other I2C devices (like the external RGB LED and GPS/Compass module’s compass) to share the same port.
Mounting to the Frame
The default mounting of the flow sensor is for it to be pointing straight down with the micro USB port pointing towards the front of the vehicle. On the back of the sensor you should see the axis printed, the X axis should point forwards and the Y axis to the right. The FLOW_ORIENT_YAW parameter can be used to account for other yaw orientations.
It is important that the flow sensor be mounted where it does not experience angular angular vibration that could blur the image.
The default mounting orientation is different to that shown on the PX4FLOW wiki. If you mount the board as shown in the PX4FLOW wiki, you will need to set FLOW_ORIENT_YAW to -9000.
Enabling the sensor
The sensor can be enabled by connecting to the autopilot with the Mission Planner and then on the Initial Setup | Optional Hardware | Optical Flow page check the Enable checkbox. Alternatively the FLOW_TYPE parameter should be set to “1” through the full parameters list. The sensor will be initialised once the Pixhawk board is rebooted.
If the sensor is reported to be unhealthy, it may help to set BRD_BOOT_DELAY to 600 (0.6 seconds) and reboot the autopilot. This will give more time for the sensor to start-up before the autopilot probes for it on the I2C bus