An opto-interrupter is like a tiny trip line, when something solid passes between the emitter and the receiver it is detectable as a change in the digital output. These are great for making very low cost rotary encoders and optical end stops. Use this with our Encoder Disk to create a simple rotary encoder.

To use this sensor simply connect the LED Anode to 5VDC and the Cathode to ground through a ~150 Ohm resistor. On the receiver side connect the Collector to 5VDC and the Emitter to a ~10K Ohm resistor (going to ground) as well as your Arduino or other microcontroller digital input.

Please Note: Encoder Disk sold separately.