myke predko wrote:
>
> Hi Gang,
>
> I *finally* got a couple of hours last night to try and dink around a bit
> with coming up with a simple TV Remote control I/R interface.  I used an LCD
> Display for showing the read-in values (more on this below).  I used a cheap
> universal remote set up as a "Sony" transimtter.

I did a lot of work on IR decoding some time ago, using a PIC chip.
I used a fast clock. Interrupt every 50 microseconds. Increment memory
counter every interrupt. Non-interrupt code zero'd the counter each transition
(change in state of I/O pin connected to the IR receiver module). The counter
values for each transition are stored in a buffer (I used a PIC chip with 192
bytes of RAM). When a long time elapsed without a transition, an end of
character was declared. Then the buffer of timer values was sent to a host
via RS232 from the PIC. The host decoded the character using an algorithm I
schemed up. That algorithm could run in the PIC chip - it's small enough.

With this, I was able to get a consistent decode of some 5 different remote
control hand-helds around the house. To emit IR from the PIC, the timer list
values are merely sent to the PIC chip and used to toggle an output bit
which controls a 38KHz 555 timer driving an IR LED.

Some remotes with which this won't work include really old General Instruments
cable boxes.

The challenge is the lack of IR character coding conventions. But...

"The nice thing about standards is that there are so many from which to choose."

stevech@pacbell.net