Hi, is it right that you con not arm without a pressure sensor? Is it possible to use a bmp280? Thx
Hi @mszilagyi, welcome to the forum 
No, that’s incorrect, although given the pressure sensor is used to estimate the depth it may be challenging to navigate without one, and you won’t be able to use depth-hold stabilisation mode.
There’s an arming check for the pressure sensor, so if you really do want to operate without one you’ll need to disable that. In QGroundControl you can do that in the Safety section by unchecking the Barometer box:
For what purpose? It can be used to measure the internal pressure of the enclosure, but I’m not aware of packages that allow it to be used in water, so not sure if it’s possible to use as a depth sensor. If you do somehow get it in a suitably water-proof package it would only work down to about 10m.
I’m not sure if it would need to be enabled somehow in ArduSub, but there is at least an AP_Baro_BMP280.cpp file in the ArduPilot barometer library, so there’s at least some possibility it would “just work” if you plug it in.
Hi, thank you for your reply!
I have an Absolute Pressure Error and I thought that is the missing sensor.
I disabled all arming checks but it’s not arming…
I’m just testing and ordered the sensor already.
I wanted to see the motor spinning…
I tried the bmp280 but it didn’t work.
THX
Martin
I can’t seem to find a way to get a window like that to appear. Which versions of QGroundControl and ArduSub are you using?
Also, if you’re not using a joystick then arming requires clicking Arm and then sliding a slider at the bottom of the main view to confirm - any chance you’re forgetting to do the slider?
HI, got it…
It was the bmp280 still at the i2c port…
you get the screen clicking on the “Not Ready”
Thank you for your help!!!
Martin
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