This sensor is great for line following or to use as part of a wheel encoder.� It will supply ~0.5VDC (TTL Off) when over a ~.25" Thick black line and ~4.8 VDC (TTL Hi/On) when over a white service.� The sensor is a Fairchild QRB1134 sensor with the necessary resistors, capacitor and hardware to get your running in no time.� For wiring the sensor follow this link.� Example OOPic code is available on our download page.