37 sensor kit box is shipped with a Infrared Transmitter sensor. Alike Line Tracking Sensor, this one also a single pin sensor, turned on infrared while got ON / High on Signal port.
Hardware Description :
The IRT sensor circuit is very simple, just consist of a Infrared LED. The sensor got 3 physical PIN, and only Signal marked as S. Well, the middle on is for Volt [5v], and last one is for GND.
S is connected to GPIO – 2.