This circuit is used to test a usb IR "PC Remote" receiver available on eBay. The USB-Serial bridge is used to communicate with the ATxmega128A1 with the custom firmware provided below. Bytes received over serial are retransmitted over IR. Alternatively, commands may be selected by pressing SW0-SW6 and then sent by pressing the SW7.
The IR transmitter circuit is simply an IR LED with a 180 Ohm resistor in series. This is fine for testing purposes, but the range is not great. A transmitter circuit can be added to increase the range of the signal.