Found this discussion, http://www.arduino.cc/cgi-bin/yabb2/YaBB.pl?num=1177181181/4
but can't understand the ir pulses format used for GetIRkey and SendIRkey subroutines. There are no examples of keys plus I don't have a IR receiver right now to catch them
As far as I know, you can't send IR info in LIRC format. The 2nd link you provided has a Flags sections that shows the IR protocols LIRC understands. You'd need to write (or find) a sketch that can output an IR signal that conforms to one or more of these protocols. Which one(s) should you use? That depends on the various devices you want to control. You may find that one device understands RC5 while another uses SIRC (Sony stuff mostly) or then again they might use an entirely different protocol.
The 2nd post in the forum link you provided will take you to a discussion (and sketches!) of the Sony and RC5 (also known as Manchester encoding I believe) protocols. You'll find both receive and transmit stuff there. I'm using the Sony receive code I found there to help me add IR capability to a wired Creative Megaworks 250D remote
For IR transmission you just use an IR led connected to a digital output, right?
Well I'd like to control my air conditioner units by mimicking their IR remote controls pulses. I think they use a custom coding for sending complex parameters like the temperature, the timer settings etc... that's why I looked for a way to get codes from LIRC files.
Anyway, seems it's better to catch the codes by myselft using a receiver.. on LIRC website there's a long list with some odds... do you have one to suggest that you're using?
I checked the first one, and he used an oscilloscope which costs 120 dollars. Really cheap for an oscilloscope (even it's software powered) but expensive for my DIY project.
I can't understand the correlation between the oscilloscope readings and the four numbers he got to simulate the commands.
Since the oscilloscope way to catch commands is ruled out, and I don't know at which frequency my IR remote modulates...
There are instructions for use an Arduino as a low res oscilloscope (i wonder if it can detect modulation freq.) or a solar cell connected to an audio card (i think it has more resolution). What can I do?
You have all the tools you need with the arduino. Set up a photo diode (or transistor) and use pulse in to measure what modulation you have. You will see bigger numbers coming out but that is only the gaps between codes. Then filter out the the modulation (hardware or software) and count the bigger numbers. These represent the gaps. Any command will consist of a number of bursts on for xmS off for ymS. You don't have to know what the numbers mean or even if you have repeated something in the sequence just repeat those numbers and play it out.
That's how I did it anyway back in 92, it was a different computer but the principal is the same.
Look here at the June issue:- http://www.doc.mmu.ac.uk/STAFF/A.Wiseman/Acorn/BodyBuild/BB92.html
Thank you Mike for sharing your experience. Wow a 1992 web page!
The only problem is how to achieve software demodulation... I have no clue on how to do that, but I'll try, maybe the solution comes up while looking at the numbers....
I could easily see the IR signals from my remote by hooking up an IR photodiode to my sound card mic input and using a sound card oscilloscope program such as xoscope. The resolution is sufficient to easily see the data pulses, but not to see the modulation. (It probably doesn't matter a whole lot if it's 38KHz or 40KHz modulation in any case.) The sound card oscilloscope isn't as good as a Tektronix TDS5034B oscilloscope, but it's about $12,000 cheaper