For the transmitter, he turned an Arduino Pro Micro into a USB sound card which he could plug into his laptop. That outputs both the audio signal and a 40 kHz carrier signal, implemented using the ...

Initially we build a transmitter and receiver to communicate between Arduinos using Morse code sent by pulses of light waves. Next, we consider digital music, which we create by switching a voltage on ...

An Arduino Pro Mini talks to a NRF24L01 which handles the wireless communication. At that point, it’s up to you – throw in as few or as many controls as you like.