Toshiba air-cooling IR remote

Hello.

Project is still in meditation phase. I have not checked yet with my
osciloscope, but I fear a coming problem.

I want to customise a Toshiba air-cooling system using an rPi and LIRC.
The hardware is the easiest part, for once. The AC terminal has an IR
receiver, I have all electronic blueprints, and I know exactly where is
the IR receiver, the type, and how it's connected to the "brain TTL chip".
This line is a classic TTL line; I will connect it to pins 13 and 14 on
the rPi which are IO 22 and 23. In the worst case, I will need a level
adaptor (to convert between 3.3 and 5V).

This will allow the rPi to listen to any incoming signal from the IR
remote, and also send orders to the AC terminal. The only "bad" side
effect is that any signal sent by the rPi will immediately be received; I
will have to ignore such frames.

I have to aims.

1: of course, send orders I like from the rPi (record orders from the
remote, and replay them later; that's the easy part).

2: over-write orders I dislike. Lirc will have to decode all incoming
orders, understand what they mean, and, if I don't like them, send new
orders to the AC terminal (within  30s).

The problem I suspect: AC systems do not have simple IR remotes like TV;
they contain multiple orders in the same IR frame; the same IR frame may
contain all this grouped together (not 100% certain yet, but that's what I
fear, and need to check):
- set terminal on
- set temperature to 19
- set fan speed to 3
- set oscilator with speed 2

As far as I know LIRC, it records static frames (buttons). But in my case,
if I am correct ... sending order to set 19° can have over 20 variations
(5 different fan speeds, 5 different osc speeds, plus timer issues). I can
not make LIRC learn all possible fan orders that may be grouped with every
single possible temperature. That would make a huge database, and it would
take me hours to produce each possible combination; and of course, I may
forget some.

My need, regarding LIRC, is to ask LIRC to only learn about bitrate, and
how to convert IR frames into binary words (convert timings into binary),
and then, send the received code to a shell script. Then, my shell script
will examine the content of the frame, and analyse which byte is the
temperature, which byte is the fan speed ...

Can LIRC do this ? How ?

I don't need LIRC to handle any button. There are no other IR devices
around; avec even if there are, my shell script will detect which frames
are for the AC, and which frames may be intended for a TV or something
else. I only need LIRC to convert frames into binary words, and launch
(call) my script, with that data as argument.

Then, my script will eventually build a frame to send, and ask to emit it.
The script will also handle the case where each frame sent by the rPi will
be received, and of course, ignore that frame if it's identical to the one
I just sent ... my problem.

-- 
 >o_/ DEMAINE Benoît-Pierre (aka DoubleHP) http://benoit.demaine.info/
If computing were an exact science, IT engineers would'nt have work \_o<

"So all that's left, Is the proof that love's not only blind but deaf."
(FAKE TALES OF SAN FRANCISCO, Arctic Monkeys)

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