So the new IMU + PCB + Raspberry Pi passed the first stage by having no I2C errors. Next step was 0g calibration at a reasonable temperature which produced good results. Final step then is to power up the motors and ensure I’ve got all 4 to spin the right direction (testcase 1 in the code).
And that’s the next problem: the front right prop didn’t spin and the ESC didn’t shut up (they whine annoying when they are missing a PWM signal), suggesting something was wrong with the PCB or model A+ itself.
Now, I had 2 spare model A+’s and a very vague memory one was duff in some way, but I couldn’t remember which or how. So I swapped the model A+ over, and at the same time double checked the PCB and resoldered a couple of joints that looked slightly dodgy.
The result? All four blades now spin, but the I2C errors are back! It’s enough to drive you nuts – luckily I was nuts anyway just to take on this project!