The Sharp GP2Y0A21YK0F infrared distance measuring sensor uses a beam of infrared light to reflect off an object to measure its distance. Because it uses triangulation of the beam of light to calculate the distance, it is able to provide consistent and reliable readings which are less sensitive to temperature variation or the object's reflectivity. The sensor outputs an analog voltage corresponding to the distance of the object, and can easily be read using an inexpensive analog to digital converter (ADC) chip.
The Sharp IR Sensor Stand kit (725-28995) provides a very convenient method of mounting the sensor, and the Sharp IR Sensor to Servo Cable (805-28995) makes it easy to wire up to a breadboard or microcontroller board.
Distance measurement range: 10 to 80 cm (3.9 to 31.5 inches)