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Problems with Bar30 and ArduSUB on Pixhawk 4


I’m trying to build an ROV which should hold the depth and control the pitch angle in an aquarium.
I’m able to read the ATTITUDE values with a Python-script.
For the depth I tried to connect the new ordered Bar30 to my Pixhawk. For that I needed to change the plug to the new I2C one.
After solder the wires together like the descriptions said, I plugged the sensor in, but calibration fails on ardusub.
I changed the software to ardupilot and there the calibration was succesful, but i cant read any data.

I hope for some help to get the sensor work under ArduSub.

Thanks for ur help.



You may need to change BARO_EXT_BUS so it is able to find the sensor in the correct bus.
I’m not sure of what is the correct bus in the Pixhawk 4, so you may need to experiment.

If you get it working, please report back so we can add that as a default in the Firmware.

Thank u for ur fast answer.

I tried the possibilities disabled, bus 0 and bus 1, but no one worked for me.
I’ve already tried it because of other entries in the forum.

It says:
‘Requesting pressure calibration…
Depth sensor is not connected.
Pressure calibration fail’

The Pixhawk 4 seems to have 4 i2c buses, so try to increase it up to 4. and reboot the autopilot each time.

Have you tried -1?

Hi @Hans12323, welcome to the forum :slight_smile:

The Pixhawk 4 hasn’t been supported until very recently, so there isn’t a stable release for it. To use it with ArduSub you’ll need to use the Development release (ArduSub 4.2) or the Bar30 won’t work, as covered in this thread:

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After changing to the dev build 4.2.0 and putting the BARO_EXT_BUS to 3 the calibration finally works.

Thanks guys, keep up your great work.