ON Semiconductor Miniature Reflective Object Sensor. The ON Semiconductor QRE1113 a reflective object sensor in a miniature through hole package format. This small 4 pin package is just 3.6 x 2.9 x 1.7mm and is also available in gull wing form ( ; 761-3984 761-3984 ). The sensor uses a diode to emit a signal then the phototransistor detects this signal back to detect objects within a given range. Phototransistor output No contact surface sensing 4-Pin configuration Miniature Through hole package 2.9 x 3.6 mm footprint