Great drone....except that barometer changes when battery and GPS plugged in

ArduCopter Copter 4.0
1

Using Copter 4.0.5 on a kakute F7 board with a BN-880 GPS & Compass, the barometer reading is fine when plugged into USB, the moment that I plug battery in Altitude changes erratically from approx -3000 m and back to 0 m.

Strange thing though is that if I disconnect the BN-880 GPS (RX6/TX6) & Compass (I2C) and plug the battery in then the barometer is fine?

I’ve attached a log file, taken with drone on my desk, no props with everything plugged in, the Baro - ALT shows this erratic behavior. Spent the last 3 days trying to figure this out with no success, ANY advice would be greatly appreciated.

4 1970-01-01 02-00-00.bin (650.0 KB)

2

OK so figured this out, seems so damn obvious now but gave me a lot of issues, hopefully this can help someone else with a Kakute F7 board and a BN-880 compass/gps. Wiring your BN-880 to the 3.3V rail and not the 5V rail as instructed in the manual, barometer issues solved immediately. My assumption is that this is because the kakute i2c baro works on 3.3V so if you connect the i2c compass to the 5V rail it conflicted the signals.