Brand-new Pixhawk not starting

[EliotBR (Eliot)]

Hi @monsterbacke,

@monsterbacke

When everything is connected and we start QGC, we get the video from the companion without issues, but QGC keeps saying “Disconnected” in the top left corner and the Pixhawk also can’t be reached via mavlink or QGC’s Firmware Setup page.

Please try going through our troubleshooting steps, and if they don’t manage to fix the connection issue then please let us know the results from each step

@monsterbacke

Here is a video of the behaviour on start-up:

https://owncloud.fraunhofer.de/index.php/s/W6PWgnvkBsEx6ra

Note the big LED is quickly changing between amber and a light purple colour, but FMU and IO seem to be fine.

And this is the sound it makes, a bit like a fire alarm:

https://owncloud.fraunhofer.de/index.php/s/pAAZ0McHuVoeSqx

ArduSub by default expects a Leak Sensor to be connected to AUX port 6. That leak sensor is effectively a ‘normally closed’ switch, which becomes ‘open’ when one of the probes comes into contact with water, so if it’s not plugged in ArduSub thinks there’s a leak and engages the Leak Failsafe.

If you don’t have a leak sensor then you should be able to disable the leak sensor failsafe in QGC on the Safety Setup Page. If it’s annoying while you’re trying to get the connection working via Companion, plug the Pixhawk directly into the topside computer and turn off the failsafe before reconnecting it to Companion and continuing the troubleshooting steps

@monsterbacke

In the documentation for ArduPilot/Copter I found a page on the meaning of several LED combinations and sounds. However, none of these seem to apply to what we are observing. What could be wrong?

While the ArduPilot docs match our behaviour for the most part, we don’t yet have proper documentation for how the various LEDs/sounds work with ArduSub. It is something that’s in the pipeline, but we unfortunately haven’t yet had the time to complete it.