Pololu QTR-1A Reflectance Sensor (2pk)

The Pololu QTR-1A Reflectance Sensor carries a single infrared LED and phototransistor pair in an inexpensive, tiny 0.5" x 0.3" sensor module that can be mounted almost anywhere and is great for edge detection and line following applications. The LED current-limiting resistor is set to deliver approximately 20-25 mA to the LED when VIN is 5V. The current requirement can be met by some microcontroller I/O lines, allowing the sensor to be powered up and down through an I/O line to conserve power.