Arnaud_M:
My problem is that the value from sensor (after treatment ) is still moving up or down.
I can memorize max end min angle, (thx to clever functions) but how to code in order to stabilize position ?
It's normal for a gyro to output constant movement even when at rest. This is referred to as "drift". A drift around 10 degrees/second is typical.
If you can add some point of reference for the position of the wiper blade then you can eliminate the drift error everytime the blade passes that point. In other words, if you used a limit switch, hall sensor/magnet, or optical sensor that would tell you everytime the blade is at the midpoint between the min/max sweep then you would know that you need to turn a set amount of degrees more from that point. The drift would not be a big issue then.
Regarding inclinometers, those still employ accelerometers. They're not going to help you here.