IR Infrared Obstacle Avoidance Sensor (2pcs) IR Transmitting and Receiving Tube Photoelectric Switch 3-pin Compatible with Ar-duino Smart Car Robot

By simply placing an Infrared Sensing Stickers, the range is much greater than 12 inches.

Total waste of money. Doesn't really work and if you see some reviews stating how good it is and works, be weary. I sent it back.

There are equivalent offerings available at a much lower price. The divergence of the IR LED beam - like most 5 mm LEDs - is about +- 30 degrees. Consequently, the detection range is limited to about 5-6 inches, as advertised. (Note: Polishing the LED flat increases the beam divergence to about +- 60 degrees.) Also, black objects tend not to reflect well at the wavelength (0.9 um) of the IR LED, and so are not seen. I converted this product into a broken-beam sensor by demounting and remoting the LED and photodiode facing each other. The broken-beam sensor I made works at a separation up to roughly 11-12 inches.

The units I got were assembled using 1-turn potentiometers which don't have nearly enough resolution to allow you to adjust the sensitivity correctly. Working units of this design will use 10-turn potentiometers.

So... they do work. and will likely work well for you if you don't mind the max sense distance to be around 3CM not 30CM. I tested this at 5V.The pot is only really useful in about 40% of the range and set any higher will just cause a full on state even with out any light from the emitter. Yes in a dark room too. I also covered both sides with electrical tape. Its just not a good pot or maybe the circuit is sub optimal.

The product description on the Amazon site is unintelligible. It would be useful to have a link to the data sheet.