LIRC guide for FreeBSD

Andrew Milton akm at
Sat Mar 17 08:07:10 UTC 2007

+-------[ Joe Auty ]----------------------
| Cool, so this is just a matter of software configuration then?

You need some strobing code.. this is assuming you don't have something neat like
a niveus IR blaster.

| Any
| ideas how I can setup LIRC to do this?

For your device that you want to send to, you need to know two things (other
than the codes).

Pulse width, and the carrier frequency.

The pulse usually consists of an on then an off period,
so a '1' is an on/off period, and a '0' is an all off period.

 |   |
-+   +---+--------
 |   |   |   |   |
 |-  1  -|-  0  -|

OK, now inside the part of the pulse that's high, you need to strobe the
correct control line at the carrier frequency. These are normally in the 
range of 37Khz - 40Khz for consumer infrared.

You need to find out the remote codes for your device, there's plenty of
remote sites out there that have CCF files or whatever (if there's no LIRC
config that has them), that should give you what you need to send.

Once you have that you simply set up your lirc config to run your 'send' app
when ever it receives your incoming button and tell it to send the write code. 
You can also then use this to directly send commands to it etc from the
commandline or whatever.

I used to have code to handle all this (as well as an IR receiver app that had
dvico USB receiver code, it had a LIRC output mode, so that applications that
used the LIRC lib could work with it). I had a look on a few DLT cartridges,
but, I can't find it. I basically had learnt codes for heaps of remotes that I
had lying around, TV Remotes, DVD Remotes, XBOX, PS2. I guess I should make a
better effort to find it.

It's not really rocket science to build a receiver / sender system. The
"hard" problem is if you want to learn codes from remotes in some sane fashion.

Andrew Milton
akm at

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