The Crowbits-Adjustable Infrared Sensor features a high-sensitivity photo reflector to perform distance detection function, ranging from 3cm to 80cm. When the infrared light emitted by the emitter gets reflected on a surface that blocked it, the phototransistor can pick up the signal for distance calculation. Also a potentiometer for adjustment is arranged for easy and clear use. It is small, easy to use/assemble, and inexpensive. Useful for robotics, interactive media, industrial assembly line, etc.