AVR-Chat

If you can find or figure out the bitstream for each command, then
you won't need to capture into the micro, but just program them
into EEProm.  You can usually find the bitstreams somewhere on-line
or from the manufacturer - at least this is true most TV remotes.
To observe and note the bistreams, attach your scope to the
demodulator output.  Set the transmitter and receiver at a moderate
distance apart, and keep ambient flourescent lighting to a minimum;
as you noted, the pulse widths do vary somewhat depending on
condtions.

Ken



>              My first idea is not to use a receiver with built-in
> demodulator, because i don't now how to reproduce the
> modulation, and if is a larger modulation start bit or
> wherever (I'm saying this because i've tried to see a little
> of the signal in a "Communication Analyzer" and the start and
> stop bits is different of the middle.
>  I'm thinking in reproduce the signal already modulated, since is only 1
> and 0, i think its easier, or not?
>     Aren't you using the common 38Khz receiver that has a built-in
> demodulator?  That will automatically produce the slow command  data
> that can then be easily captured by the micro, by sampling or edge
> interrupts.             Hi again,  My objective is to read a Infrared
> command signal (Airconditioner remote command), that is modulated in
> 38Khz, to later reproduze the commands, i've past the signal to TTL
> and the question is, what is the best way to read that signal?  I'm
> using ATMega128 and a crystal of 15.3Mhz to be 100% with USART.
> External Interrupts? Timer/Counter? 8bit? 16bit? Counter1? Counter2? I
> will need to read at least at 76Khz (2x38Khz), right? My first idea is
> to use a internal interrupt that occurs at a rate bigger 76Khz, and
> see if the signal is at 1 or 0, is this the best?        Yahoo! Groups
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