We have a Hitachi ED-A101 projector. It has a moving mirror, i.e. when it turns on, the mirror opens, and when it turns off, the mirror closes. For this to work, the projector has a DC motor, plastic gears and a metal axe for one of the gears. It is not a good combination, that plastic gear easily wears out because of the sharp edges of the axe. This is a typical problem with this projector. We tried to repair the gears (it is not easy to replace the gearbox), we even printed that gear, but it did not work for too long. So we tought of solving this problem in a different way: fix the mirror and simulate the opening/closing process for the projector.