USB HID with Infrared Feature

The project was designed with capability of converting CIR signals from a remote control to keystrokes and/or mouse movements.

An ATmega8 AVR microcontroller is being used on this gadget along with the Objective Development firmware-only USB driver stack. A TSOP1738 infrared receiver and demodulator are contained in the device which is responsible for picking up the signals from the remote control. A combo HID device is implemented by the microcontroller by simulating a mouse and a keyboard. This is how the movements of the mouse can be sent together with double clicks, and keystrokes to the PC.

One good feature about this device is that it works out-of-the-box without requiring any special software since most modern operating systems or Windows have built-in HID drivers. A TV tuner unit with Leadtek CoolCommand RM-100 label was used as remote control. The protocol applied is constant-length, space encoded revealed by LIRC analysis using xmode2 and IR record. This signifies that all codes have the same total length of around 108mS.

Since the IR receiver has open-collector output, the VS pin of TSOP1738 is connected directly to the +5V line of USB instead of the 3.3V Vcc.

Rest of the project