A power tool includes a housing, an output shaft having a tool axis, and a motion sensor that senses motion of the tool housing. A control circuit receives an input signal from the motion sensor, to make a first determination, based on the input signal, wh...

Device comprises a light source (2) emitting light beam (25), first (110) and second (120) two-dimensional opto- electronic sensors. The two sensors can be aligned so that light incident of the opto-electronic surface of the first sensor is partially refle...