Since first introduction of the BBBMINI and then BBBMINI-PCB beginning of the year, there are a lot of improvements and test flights done. As the result we get a low-priced, reliable and up-to-date DIY Linux Autopilot runs ArduPilot software.
With the merge of EKF2 (Extended Kalman Filter) in ArduPilot master, you can add easily a second IMU as its own instance to the BBBMINI. I tried that and attached a second MPU-9250 (GY-9250 breakout board, about 6$) to the unused BBBMINI SPI0 pin header. With a small patch I get the second IMU (and compass) up and running. After changing the ArduPilot configuration, both IMUs appears at the GSC and in the log files. Finally I have to do a compass and accel calibration.
After some “flight” checks with dismounted propellers my “250 BBBMINI Indoor Test Quad” was ready for the first dual IMU flight.
The Quadcopter is not yet tuned, but it fly much better than expected. I flew indoor 7 minutes in Alt-Hold and the Quadcopter only moves about +/- 50cm in height, I only did some small pitch and roll commands to keep the Quadcopter in position. I am happy with EKF2 dual IMU and I am looking forward to test it outside (with GPS) when the weather conditions allow it.
The film below shows what happens when you unplugged one IMU “in flight”, the Quadcopter should be still flyable, but that is not tested ;-)