About this item

The SparkFun Line Sensor Breakout (QRE1113 Analog, ROB‑09453) is a compact, three-pin module optimized for line-following robotics and reflectance detection. It integrates an IR-emitting LED and phototransistor, with a 100 Ω resistor limiting LED current and a 10 kΩ pull-up resistor on the output. As IR light reflects off surfaces, the phototransistor's output voltage decreases—white surfaces reflect more, resulting in lower voltage, while darker surfaces produce higher voltage. It operates on 3.3 V or 5 V supplies, drawing about 25 mA, and has an optimal sensing distance of around 3 mm. The tiny PCB includes a mounting hole and measures roughly 7.6 × 14 mm.