Line Follower click carries an array of five QRE1113 miniature reflective object sensors. As the name implies, Line Follower click is best used for line following robots and cars. Each one of the QRE1113 sensors consist of an infrared transmitter and infrared receiver. Digital output.
IR reflect click carries a GP2S700HCP reflective photointerrupter and an onboard potentiometer. On this type of photointerrupter the infrared emitter and receiver are facing the same direction; the infrared beam from the emitter gets bounced back to the receiver when an object is placed within the detecting range of the sensor.