I'm working on a free space optics project to send data wirelessly between two points. To accomplish this I'm using an IR LED connected to an Arduino Uno that pulses with a 56 kHz carrier frequency for the transmitter and a second Arduino with a 56 kHz IR detector module for the receiver.

I tried using delayMicroseconds() between pin high and pin low commands in order to create the carrier frequency. This kind of works, but the frequency isn't always the same and any additional delays for pulsing the signal (i.e. the time required to call the function and decrementing) can change it.

Reading the datasheet for the ATmega328 it appears that there is a way to set a more accurate pulse using the chip's timers. Is that possible, and if so, how do you create a 56 kHz pulse using the timers?