This is a Canon ESM and at the left is an Arduino Nano with an infrared LED hooked up to it. The Nano is telling the LED to flash about every 5 seconds and when the LED flash is in front of the camera where the infrared sensor is, the camera takes a photo. Here the same thing is happening but this is an infrared video so you can see the infrared LED flash at the same time the little LED on the Nano flashes. But the flashes are pretty weak here. There's a shield on the other side of the Nano that makes it easy to connect things to it. You can see the infrared flashes better here and also the simultaneous LED on the Nano below the green power LED. The infrared LED is not just flashing but it's emitting two bursts of really short pulses, each one just 15 millions of a second long. The pause between the two bursts is of a precise length and this is the signal the camera's program to respond to. Right next to the camera's infrared sensor it has an indicator LED which flashes when a photo is taken. The sensor picks up the infrared signal whenever the infrared LED is in front of the camera. It even works to bounce the infrared light off the filter on the front of the video camera.