This page lists some frequently asked questions and problems that often occur, and how to solve these issues. Please have a look at this page before you ask for help in the community.
Many problems are solved by simply switching the device off and on. This goes for both the RDDRONE-FMUK66 and your computer. If you can't connect with your drone, first try to switch it on and off, and also try restarting the software you are using, or reboot your PC.
Originally there were some issues with the Windows driver that comes with QGroundControl. It did not recognize and support the RDDRONE-FMUK66. If this occurs again in future then once again Flashing firmware via QGC may be impossible.
Flashing firmware using the debugger should always work, even under Windows. Otherwise, it might be a good idea to setup a virtual machine with a Linux OS. The Linux version of QGroundControl does recognize the FMU, and this also works in a virtual machine if you set up the USB passthrough correctly. Note that the FMU has a bootloader which is seen as a separate device during boot, you will also have to add this device.
One of the HoverGames reported the following issue: "I had FMU communications issues recently. QGroundControl was no longer detecting FMU/Telemetry. In my case, it turned out the Bluetooth controller included in my laptop (Dell Latitude E7450) was creating UARTs COM ports conflicting with FMU/Telemetry, preventing QGC to detect the new ports. To work around this connection issue, just temporarily disable the Bluetooth in Windows 10 (for example, in the bottom right notification area menu, set the Bluetooth OFF), unplug FMU or Telemetry cables, then restart QGroundControl."
Make sure there is actually a bootloader on the board, and that the firmware is working correctly. When first powered on the Bootloader will flash the yellow LED while in bootloader mode. If you are having difficulty you can follow the flashing instructions, and re-flash both the bootloader and firmware using the debugger.
Check if you can power the FMU at all. If the FMU works fine when the battery is connected, but not when only USB is connected, it could be that fuse F3 is blown. Please see the page about the fuses on the RDDRONE-FMUK66 board.
If the motors are not spinning at the right speed, or are not reacting properly to changes in the throttle input coming from the controller, there are quite a few things to check.
Check the electrical connections, see if the bullet connectors coming from the motors are completely plugged into the ESCs, and check if the ESCs are soldered in the right way and if they receive power.
Also make sure to check your RC configuration on both the transmitter (controller) and the FMU. Also check with the information in the radio tab in QGroundControl if the signal is properly received.
The airframe must be set, and to get accurate results the motor calibration should be completed. After ensuring the propellers are removed for safety, from the console you can issue the following commands to directly test and exercise the PWM outputs:
- The fmu test command will sweep all the PWMS up and down repeatedly
- The pwm command will let you individually control the pwm output channels as configured by your specific airframe and mixer settings.
>pwm test -c 1234 -p 1300
>pwm -test -c 24 -p 1630
You can use the -c parameter to select which channels you want to use. With the -p parameter you can select the pwm value.
It was reported that MAVLink v2 is not always used when it should. By default, PX4 uses MAVLink v1, unless v2 is supported and requested to be used by the connected device.
A possible solution is to set the
2, to force all MAVLink connections to use MAVLink v2. Note that this makes it impossible to use devices that only support MAVLink v1!