Sharp I.R. modules (RX) are sold by Dick Smiths, 38KHz.
You MUST use an AGC pulse unless the PWM bursts are exceedingly long, as
to the S/W implementation, try to arange TMR0 ISR to be greater than the
total code burst for easy code writing.
regards,
Graham Daniel.

Jinx wrote:

> Hello helpful all. I'm starting the last stage of a project which
> needs two synchronisedcount-down clocks. Think I know how I'd like to
> do it but would appreciateany thoughts members have. Each clock is
> built around an F84. Readout is a 4-digit 12mm LCD,showing either
> Hh:Mm or Mm:Ss. The two clocks are separated by 30feet. They are
> identical except that one is a master, the other a slave.The slave
> needs to start with whatever time is set on the master. Itshould also
> Pause/Unpause or Reset when told to by the master. Thenecessity is for
> one-way IR communication from master to slave. Onepossibility which
> may foul this up from time to time is coinciding IRQs. The plan is to
> have the master enable its Timer0 IRQ first and the slaveonly enable
> its IRQ after receiving the first pulse of IR from the master.
> Theslave would delay about 1/2 an IRQ period, so that the IRQs of the
> masterand slave are well and truly separated in time. As each digit is
> in the range0-9 I could send a wake-up pulse of 2 IRQs length and then
> 4x4-bit nybbles,using 1bit per IRQ. Both clocks would then start their
> count-down as soonas the IR transmission had finished. The time
> difference between the displayswould be the 1/2 IRQ. Pause/Unpause and
> Reset could be 1010 and 1011. Is there anything glaringly obvious I've
> overlooked ? The IR receiver has been taken from a trashed VCR. I've
> tried a few discretedesigns in the past but never managed to come up
> with anything as effective.Although the power consumption is sort of
> OK at 1.5mA at 5V (the slaveclock is on battery power), if anyone
> knows of a circuit as good as a VCRreceiver at lower power I'd be
> interested. regards, Joe PS there's a printer utility called FinePrint
> that will condense several pagesonto one sheet. I've used it for a
> while to save paper when printing listings. 4pages per sheet is about
> the limit of readability. I found it at download.comunder Utilities /
> Printer.