Quoted from Valorguy:
I am so confused by the pinguy app. Do i lay it on a flat (hopefully flat) surface and calibrate, then turn 180 around and do the same, BEFORE i put this on the playfield?
It doesn't explain very well and I'm no field engineer.
Correct, the calibration procedure should take out any error in level of the surface you are calibrating it on. That is why you are asked to turn the phone 180 degrees. True level must be between these to measurements. Same way you calibrate other digital levels (ones that I’ve used) and traditional bubble levels.
The only thing to watch out for using you phone is the pesky camera bump on the back. It may rock back and fourth. Most cases are thick enough such that the camera bump is recessed, but ensure the back of your case is a flat plane. I’ve had to make a couple 3D prints to get around some of these issues.
I would try a couple dozen games and then adjust the pitch and see how it plays at a few different pitches. It took me a while to dial in JP2, I think I’m at 6.8 degrees. Two or three tenths makes a big difference on that game.