Applications: 
Smart car or robot hunt (including black and white lines), walking path along the black line, also known as tracing. 
smart car to avoid the cliff, fall. 
Smart car to avoid obstacles.
detection of reflective material, such as paper, tape, card, non-contact IC card and so on.

How to use: 
sensor interface 3 pin, VCC, OUT, GND. VCC and GND to the supply terminal, and OUT is a signal output terminal. Detected objects output low signal terminal; does not detect objects, signal-side output high.
determination signal output terminal is 0 or 1, and will be able to determine whether the object exists.

Performance parameters: 
detection distance detection White about 2 cm. Depending on the color of the different distances from different white furthest. Supply voltage: 2.5V to 12V, should not exceed 12V. (Note: The best low-voltage power supply, shortens the life of the supply voltage is too high sensor. 5V supply is better.)
operating current, from 5V when 18 to 20ma. After extensive testing, the sensor hardware is set to 18 ~ 20ma current best performance, mainly in the anti-jamming capability. If a customer needs a small power consumption, the shop also can modify the minimum can be done 5ma. Can photographed Message marked. Detected objects, output low signal terminal; does not detect an object, signal-side output high.Sensor output TTL level, can be connected directly with 3.3V or 5V single-chip IO.

Black line or white line detection principle
using the black light reflectance this feature, when the plane of the color is not black, the sensor emitted infrared light is reflected back. Thus the sensor outputs a low level 0 when there is a black line in the plane, the sensor when black line side, due to the weak black reflectance infrared light reflected back up to the level of no sensor operation, the sensor output 1.
as long as we judge with SCM sensor output of 0 or 1, black lines can be detected.
principle of detecting white line and black line detection principle to detect the white line, white line surrounding the color should be relatively close to the black, then adjust the infrared sensor above the adjustable resistance will reduce the sensitivity, has been transferred to just the surrounding colors undetectable until, as can be detected white line.