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Warning, Critically High Internal Pressure

What could be the cause of the alarm ‘Warning, Critically High Internal Pressure’?
Where is the pressure sensor located?

Hi, the pressure sensor may be show a warning if the pi has over throttled and heated the interior of the electronics enclosure, or if you’ve had an increase in temp over the last few day’s.
Remove the vent plug and allow the machine to rest for a bit, (if bench testing leave the plug out, just remember to reinstall it before a dive)


Thanks Craig. I was asking for a friend who had spent a long time with the vehicle powered up out of the water.

Agreed with @murf - the electronics enclosure isn’t intended to be run extensively out of the water, because it can overheat. If it needs to be run for a while in air then keeping it vented is a good idea. To avoid thermal throttling it would likely require either an aluminium enclosure, or taking the enclosure off the e-tray so it’s able to get consistent air-flow.

The Pixhawk has a barometer as part of its inbuilt sensor suite. I believe that’s mostly there for detecting altitude while flying (since the Pixhawk specification was designed for primarily aerial vehicles).

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Thanks guys. I knew you shouldn’t leave the BR2 powered up in air for any length of time, but I didn’t know the PIxhawk had an internal barometer. You learn something new every day!

If you’re interested in knowing more about the Pixhawk, our Autopilot docs link to the PX4 organisation’s Pixhawk 1 docs. As far as I’m aware the only difference from the original design is that the FMUv3 specification is now used instead of FMUv2, to correct “a bug that limited the original Pixhawk 1 to 1MB of flash [memory]”, but that’s a minor firmware difference so all the sensors and other hardware components should be the same as what’s specified on that page :slight_smile: