This article describes how to setup the PX4FLOW (Optical Flow) Sensor which can be used in place of a GPS.

HOME SOLUTIONS DRIVE AGX DRIVE Hyperion DRIVE Software DRIVE OS DriveWorks DRIVE AV DRIVE Perception DRIVE Mapping DRIVE Planning DRIVE IX DRIVE Constellation DRIVE Sim NVIDIA DGX DOWNLOADS DOCUMENTATION TRAINING COMMUNITY This page provides access to software for developers using NVIDIA DRIVE™ AGX, DRIVE Hyperion and DRIVE PX 2 Developer Kits. Open PuTTY; on the main screen, use the following settings: Serial / COM14 / 115200. Replace COM14 with the COM port number you wrote down previously. Feel free to type in a name and hit “Save” to remember this configuration. After the installation of Net Framework 4.0, you can download the Mission Planner Installation Package. (The latest version is recommended) Note: two different versions, MSI and ZIP are provided on the download page. MSI is an application installation package, PIXHAW USB driver will be installed together with the Mission.

Warning

The PX4FLOW is not yet supported in Plane or Rover.

Overview¶

The PX4FLOW (Optical Flow) Sensor is aspecialized high resolution downward pointing camera module and a 3-axis gyro that usesthe ground texture and visible features to determine aircraft ground velocity.Although the sensor may be supplied with a built-in Maxbotix LZ-EZ4 sonar to measureheight, this has not been reliable enough over a range of surfaces in testing, so itsreadings are not used. It is recommended to purchase a PX4Flow device without the sonar.Instead a separate Range Findersuch as the LightWare SF10bshould also be attached to the vehicle.

Warning

To best use this flow sensor you will need to purchase a separate rangefinder like the LightWare SF10b

Install Drivers (Windows only)¶

On a Windows machine a “PX4Flow” device should appear in Connection drop-down of the Mission Planner (and the Windows Device Manager), or be automatically recognized by QGroundControl. If it does not you may need to download, unzip and manually install the px4flow windows driver which may in turn require allowing installing unsigned drivers.

Using MissionPlanner¶

1. Download and unzip the PX4Flow-KLT firmware(source code here)

2. Connect the PX4Flow sensor to your computer using a micro USB cable.

3. Open the Initial Setup, Install Firmware screen, select the COM port and click the “Load custom firmware” link. Select the px4flow-klt-06dec2014.px4 binary you downloaded in Step 1. You may need to unplug and plug back in the sensor to start the upload.

4. Disconnect and reconnect the sensor/USB cable

5. Select the appropriate COM port and press Connect

6. Open the Initial Setup > Optional Hardware > PX4Flow screen

7. 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

Using QGroundControl¶

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.

1. Select the Vehicle Setup page, and click the Firmware tab.
2. Connect the PX4Flow sensor to your computer using a micro USB cable.
3. 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.
4. Unplug and replug the sensor. Two extra tabs should appear: “PX4Flow” and “Parameters”.
5. 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.
6. Download and unzip the PX4Flow-KLT firmware(source code here)
7. Unplug the sensor, click on the “Firmware” tab and replug the sensor.
8. 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. Inmost cases an I2C splitter should be used to allow other I2C devices (like the external RGB LED andGPS/Compass module’s compass) to share the same port.

PX4 FLOW (COM14) Driver Download

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 experienceangular angular vibration that could blur the image.

Note

The default mounting orientation is different to that shown onthe ETH PX4FLOW wiki. If youmount the board as shown in the ETH PX4FLOW wiki, you will need to setFLOW_ORIENT_YAW to -9000.

Enabling the sensor¶

Px4 Flow (com14) Driver Download Windows 10

The sensor can be enabled by connecting to the autopilot with the Mission Planner andthen on the Initial Setup | Optional Hardware | Optical Flow pagecheck the Enable checkbox. Alternatively the FLOW_TYPEparameter should be set to “1” through the full parameters list. Thesensor will be initialised once the Pixhawk board is rebooted.

Testing and Setup¶

See Optical Flow Sensor Testing and Setup

QGroundControldesktop versions can install PX4 Pro or ArduPilot firmware onto Pixhawk-family flight-controller boards. By default QGC will install the current stable version of the selected autopilot, but you can also choose to install beta builds, daily builds, or custom firmware files.

QGroundControl can also install the firmware for SiK Radios and PX4 Flow devices.

Loading Firmware is currently not available on tablet or phone versions of QGroundControl.

Connect Device for Firmware Update

Px4 Flow (com14) Driver Download Pc

Before you start installing Firmware all USB connections to you vehicle must be disconnected (both direct or through a telemetry radio). The vehicle must not be powered by a battery.

1. First select the Gear icon (Vehicle Setup) in the top toolbar and then Firmware in the sidebar.

2. Connect your device (Pixhawk, SiK Radio, PX4 Flow) directly to your computer via USB.

   Connect directly to a powered USB port on your machine (do not connect through a USB hub).

Select Firmware to Load

Once the device is connected you can choose which firmware to load (QGroundControl presents sensible options based on the connected hardware).

1. For a Pixhawk-compatible board choose either PX4 Flight Stack vX.X.X Stable Release or ArduPilot Flight Stack radio buttons to download the current stable release.

   If you select ArduPilot you will also have to choose the specific firmware the type of vehicle (as shown below).

2. Check Advanced settings to select specific developer releases or install firmware from your local file system.

Update the firmware

1. Click the OK button to start the update.

   The firmware will then proceed through a number of upgrade steps (downloading new firmware, erasing old firmware etc.). Each step is printed to the screen and overall progress is displayed on a progress bar.

Once the firmware has completed loading the device/vehicle will reboot and reconnect. Next you will need to configure the airframe (and then sensors, radio, etc.)