This reflectance sensor module is designed for use with the Zumo shield for Arduino. It has six IR LED/phototransistor pairs that can be used for line following or edge detection; each sensor provides an independent, digital I/O-measurable output. The array draws approximately 40 mA when the emitters are on, and an optional input allows the emitters to be turned off for additional sensing or power-saving options.
The Zumo reflectance sensor array provides an easy way to add line sensing or edge detection to a Zumo robot. It features six separate reflectance sensors, each consisting of an IR emitter coupled with a phototransistor that responds based on how much emitter light is reflected back to it. The two outside sensors are positioned at the very edges of the module to maximize their usefulness as edge detectors (e.g. for seeing the white edge of a sumo ring) while the four inner sensors are closer together for better detecting lines. This sensor is included with the assembled version of the Zumo robot, but not with the kit version.
The sensor array plugs into the front expansion header of the Zumo shield, which provides it with power and the necessary I/O connections. The default I/O connections are to pins that are otherwise unused by the Zumo shield, but the sensor module makes it possible to remap these pins or disconnect specific sensors altogether to free up I/O lines. Please see the Zumo Shield user’s guide for detailed information about assembly and use with the Zumo robot.
More technical information at Pololu.