The Pololu QTRX-MD-13A reflectance sensor array is an analog, two-wire distance and reflective sensor that operates on a voltage range of 2.9 to 5.5 volts. It has thirteen independent channels on a single module, each featuring a reflected light LED and LED receiver. The module enables users to detect an object's position, proximity, or movement in either a line-of-sight or non-line-of-sight manner. As an analog sensor, it provides both a direct-current (DC) voltage as well as a digital output, both directly proportional to the distance of the object it is detecting. The QTRX-MD-13A is designed for stability, sensitivity, and accuracy in seeking out objects in even the most demanding applications.