The sensor we use to pick up the position was a potentiometer with end instead of an encoder.
This represent a problem for us because the complete rotation of the chair can damage the potentiometer.
At beginning we thought to made a concrete stop for the chair ’s rotation but
this was a bit triky to do in the few time we have.
Another problem was that the potentiometer under the human pressure of the body work
wrong, giving wrong angles.
We notice this just the last days because without someone sitting on it, the prototype doesn’t
give any problem.
We fix the sensor in many ways (at the bottom with a wood base and drilling an hole into the metal
in the upper part of it where is connected with the chair).
Unfortunately, after all our efforts, the potentiometer still moves while someone is sitting.
We realize the the problem consists in the bench’s structure and not in the sensor’s twisting.