GP2Y0A21YK0F Sharp IR Analog Distance Sensor 10-80cm + Cable, Arduino Compatible;

This product is a combination of Sharp sensor and 12-inch (30-cm) JST cable, offered by RobotSimple.

The Sharp distance sensors are a popular choice for many projects that require accurate distance measurements. This IR sensor is more economical than sonar rangefinders, yet it provides much better performance than other IR alternatives. Interfacing to most microcontrollers is straightforward: the single analog output can be connected to an analog-to-digital converter for taking distance measurements, or the output can be connected to a comparator for threshold detection. The detection range of this version is approximately 10 cm to 80 cm (4in to 32in)
The GP2Y0A21 uses a 3-pin JST connector (included). It is also simple to solder three wires to the sensor where the connector pins are mounted. When looking at the back, the three connections from left to right are power, ground, and the output signal.