http://tinyurl.com/n37jvn4
WYPH TCRT5000 IR Barrier Line Track Sensor Infrared Reflective Photoelectric Switch
Using infrared reflection sensors TCRT5000
The working voltage of 3.3V to 5V
Output form: digital switch output (0 and 1)
Has a fixed bolt hole, convenient installation 8, small board PCB size: 3.2cm x 1.4cm
Quantity: 2pcs