On Mon, Nov 12, 2001 at 07:04:57PM +0530, Ramana B.V wrote:
> Hi,
> I am also looking out for a cheap IR for home. Just need to send a key press
> information.
> Can someone point me to cheap IR transmitters, receivers.

The cheapest transmitter by far is any universal remote. I've seen them on sale
as cheap as tax (buy 1 and send in a mail in rebate for the price of the unit).

Receivers are as close as the local TV/VCR repair shop. Most every VCR has
a IR receiver/demodulator built in. Simply scavenge busted VCRs for parts.
Or if you're in a hurry you can pick one up new at a Radio Shack or similar
retail electronics store.

IR is on my ever increasing list of things to do. The Sony protocol seems to
be the easiest to decode. From my original study of the protocol it seems
to have a 2.4ms start bit followed by a string of Manchester encoded bits
with 0's encoded as a 0.6ms low followed by a 0.6ms high. 1's are encoded by a
0.6ms low followed by a 1.2ms high. So all that needs to be measured is the
length of the high pulse: 2.4ms -> start, 1.2ms -> 1, 0.6ms -> 0. Should be
easy to do with the CCP module if you have it.

Just some thoughts,

BAJ
> rgds
> Ramana B.V
>
>
> -----Original Message-----
> From: Simon-Thijs de Feber [mailto:stdf23173@YAHOO.CO.UK]
> Sent: Sunday, November 11, 2001 2:03 PM
> To: PICLIST@MITVMA.MIT.EDU
> Subject: [EE]: IR transceivers
>
>
> Hello,
>
> I am thinking of making an Home security system with
> IR as means of communication.
>
> As i have no experience with IR except for Remote
> controls, i'd like some advice on which devices to use
> !
>
> I can use the standard IR receivers (40KHz) but how on
> the transmitter side. ( i have to have and 40Khz
> source and have to modulate the signal on to it).
> No problem in making this, but i think this can be
> done more effiecient and simple !
>
>
> Any one an idea ?
>
>
> grtz,
>
>
> SImon
>
>
>
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