GP2Y0A21YK0F is a distance measuring sensor unit, composed of an integrated combination of PSD (position sensitive detector), IRED (infrared emitting diode) and signal processing circuit. The variety of the reflectivity of the object, the environmental temperature and the operating durationare not influenced easily to the distance detection because of adopting the triangulation method. This device outputs the voltage corresponding to thedetection distance. So this sensor can also be used as a proximity sensor.

GP2Y0A21YK0F optical sensor, detection distance 10-80cm
Sensing distance:10 ~ 80cm
Output Type:Analog
Voltage – Supply:4.5 V ~ 5.5 V
Current – Supply:30mA
When the voltage is different from the - output difference (typical):1.9V @ 10 ~ 80cm
Different voltages distance - the output (typical value):400mV @ 80cm