Path tracking sensor uses a reflective infrared sensor (tcrt500). The infrared light is emitted and reflected back to the receiver, it's then inverted by 74LS14 and output to the output pin and the LED. The output signal is a digital signal.  There...

The infrared remote control kit for Arduino consists of the receiver module, remote control and the jumper wire. The receiver module uses HS0038, the integrated receving element, which includes the sensing, amplify, recitify, and outputs the TTL signal...