Re: IR Question

[ian.bird@xxxxxxx]

Nigel's circuit takes the demodulated signal from a TSOP and the 'bus'
is
just this going from 0 to 5 volts. Normal state is high. The rest of
the
extender simply takes this signal and uses it to turn a 555 circuit on
and
off to produce the 38KHz IR.  Not RF, that would be too easy.

What Stuart needs is something that will pull this 'bus' low when IR is
to
be transmit and let it go high when no IR is needed. This obviously
happens
at the speed of the demodulated IR encoding .

My guess is your penultimate paragraph covers it but you will need to
explain it in much more layman terms. Stuart is not an expert in
electronics.

Ian

Ian Bird
CibaVision UK Ltd.
Direct dial 01489 775570
Fax           01489
779570


                                                                                                                                
                     
"Dan"                                                                                                     
                     
<dtoma@xxxxxxx>           
To:      
<ukha_d@xxxxxxx>                                               
                                              
cc:                                                                              
                     
22/10/02 14:38          
Subject:  Re: [ukha_d] IR
Question                                               
                     
Please respond
to                                                                                         
                     
ukha_d                                                                                                    
                                                                                                                                
                                                                                                                                




> I currently have an IR extender (a'la Nigel Orr) between my bedroom
and
my
> Digibox in the living room.  What I want to do is have the output
from
Dan's
> Autom8it plugin controlling the Digibox as well.

It is perfectly possible right now.


> I would rather not have an IR emitter on the back of my PC
pointing
straight
> at a TSOP IR Receiver to add the signal onto the IR extender
bus.  Is it
> possible to put the output from the PC straight onto the bus??

I don't know your extender, but I have done it with the Alcad IR
extender
(through the mains version).
If it is RF based, then is much more simple (no need for opto
couplers).

You can take the signal from the DTR pin and using a single transistor
with
the collector connected to the output of the IR receiver IC (TSOP 17xx
or
similar). This is all.

Another simple posibility is to put a LED at the TxD output through a
small
resistor and a reverse diode(for protection) in the front of the
extender
receiver....then put IRM or infrared plugin in Tx mode and.. again this
is
all... is after you which way you choose.

BR,
Dan




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