Re: IR remote control

Umbe <l_umbe@yahoo.it> wrote:

Hello,
I am trying to make a decoder for IR remote control.
I have found many sites on the internet with a loto of information.
 
I would like to start from a very low level, from a microcontroller (no
Arduino).
From where do I can start?

Look at datasheet for chip like TSOP382.  Note that the chip must
be matched to your remote (remotes and receivers use one of few
possible carrier frequencies, both must use the same).  First
check that you get sequence of pulsed from receiver chip.
Your low-level code must record lengths of the pulses.  Rest
is purely software task, you need to convert time info into
command.  There are several different coding schemes.  Hard
way would be to reverse-engineer used coding looking at
recevied transmissions.  A variation of this could be:
- first record several specimens of commands sent by the reomote
- compute average times for each command
- in decoder compare received thing with known commands, return
  the best match

Of course this variation (and reverse-engineering) works only
for coding scheme of your remote, if you want to handle different
schemes you need to get another remote using different system.

Or you can do it easy way and look how existing libraries do
it.  In particulat Lirc (suggested in another message) has
routines and tables of data for several coding systems.

--
                              Waldek Hebisch