Sharp GP2S40 Photointerrupter

The GP2S40 is a reflective surface sensor that combines an IR led and phototransistor in a single, compact package. This is one of the smallest reflective surface sensors available and features:

• Visible Light Filter
• Optimal Focal length of 3mm, usable over 6mm
• Compact Size - 4mm x 3mm x 2.4mm

This sensor is used in many of my line following robots with excellent results. The small size allows for placement of the sensors in tight spaces and it's long focal length allows for extra clearance between the sensor and the line.

Click here to view the Datasheet