The Aim IR Pick Up Sensors (719 Plug, 300cm Cable) work using a specific light sensor, to detect a select light wavelength in the Infra-Red.
IR Sensors work by using a specific light sensor to detect a select light wavelength in the Infra-Red (IR) spectrum. By using an LED which produces light at the same wavelength as what the sensor is looking for, you can look at the intensity of the received light.
When an object is close to the sensor, the light from the LED bounces off the object and into the light sensor. This results in a large jump in the intensity.
Infrared optical receiver 90cm or 3m lenght