IR is an acronym for Infrared. Infrared is electromagnetic radiation with longer wavelengths than those of visible light. It starts on the red end of visible light and extends well beyond what the human eye can see. IR is used in cameras for night vision along with read objects temperature. The most common way most people have used IR in everyday life is the TV remote. It uses IR to transmit signals to the TV. It is simple and effective way to transmit the signals and since humans can't see that light is doesn't cause any issues. The only limitation is that the remote and the device receiving the signal have to be in line of sights. The is a newer technology the uses radio frequencies know as RF remotes which don't have to be line of sight, but they are still not that popular.
