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need help w/ I.R ckt.

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New Member
hello once again I'm back with a
much more intersting topic now that i've got
a decent ps to start my projects.
i need some help designing an I.R ckt
that will be able to send two different signals
to two different receivers without mixing them
I don't have much experiece (well almost none) :oops:
with these ckt's this is what i came up with.
could someone please help me with this.
I'm completely lost here. :( anything will be greatly appreciated.
oh and i appologize for the schematic i had to use ms-paint



Why use 2 ir leds when 1 will do ?

All you need to do is have 1 transistor driver fed with 2 different signals.

2 oscillators running at different frequencies will do the job, then your receivers need to be matched to each osc.

come back if you need any more help


New Member
so the ckt final ckt would have 1 emitter ckt 2 receiver ckts

now here's another one for u how do i go
'bout building the above ckt (the osc. and fed.)


This would seem to be a good application of the LM567 PLL tone decoder.

You could encode your IR signals at 2 different frequencies, and then have a separate decoder for each frequency.

Having given you a start, perhaps you can do the rest yourself - find out how to use this chip. Give us a shout if you need help.


I believe - but anyone can correct me - that the 567 can be used for encoded audio signals. I'm not sure how - I've never tried it, but I'll do some research and get back to you.


New Member
tnx for the info i'm going to look into it

are there any equivalents to the 567
'cause i have a couple of old modems and
was wondering if i could use any of those parts.

and on a different note while i was searching for parts the
i ccame across something i had forgotten about a very old pc
an 8088 :shock: now i have no idea where i got it from
so i was wondering what can i do w/ it
and could anyone get me the data sheet for it (the 8088)
tnx :D
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