5PCs Optical Switches, Reflective, Phototransistor Output, Opto Interrupter, ITR-9608
$23.58
$32.78
Great for applications where you have to do something depending on the rotation. Simply put some paper to the rotating object and make sure it passes this switch. Then you can easily count the number of rotations.
Proximity / Tof / Ultrasonic / Pir / Microwave