Home Hacking Projects for Geeks

98

Part II: Home Entertainment

Infrared Signal Processor (Linux)

Now that you have a completed IR receiver module, you’re going to want to

make it control your computer. In this section, you’ll be building the infra-

red signal processor. Conveniently, there is free software available that’s

meant to do just that. The Linux Infrared Remote Control project (LIRC)

was created specifically for the hardware you’ve just built, but over the years

it has been significantly expanded to support an impressive array of devices

(including the IR remote that comes with the Hauppauge PVR-250 used in

the HTPC projects later in this book). There are also ports to Windows and

Mac OS X.

Take a look at the driver model in Figure 5-8. The model is made up of two

major layers: hardware and software. The hardware layer (i.e., the serial

port IR module you just built or purchased), is responsible for receiving IR

signals and transmitting them to the serial port. Of course, these signals

need something to “listen” for them; this is where the software comes in.

LIRC uses a kernel module to connect to the serial port, intercept these

signals, and pass them, unaltered, up to the decoder daemon (lircd). This is

where the real action is—the daemon decodes the raw input and dispatches

messages to other applications as directed by the .lircrc resource file.

Of course, before