RE: Re: Electronics Gurus brain required...

["i.bird@xxxxxxx" <Ian@xxxxxxx>]

Hmmm. I would have said not on tweaking the relay board much as I would
like you to have one. I assume from what I remember of these posts that you
are planning to take the HV IR out jack and then split that into 8
individally controlled outputs using portA. From there you want to split
each output again into X extensions. The extensions are all one zone if you
like and flash together.

Assuming all the above I would go back to the drawing board and build
something using the same principals but a separate power supply. Poor old
HV is limited in both its source and sink current capability.

So, using transistors and a nice power supply it should be quite easy to
do. Don't forget some nice decoupling capacitors as the IR LEDs draw a
reasonable current and better safe than sorry.
*********************HOW TO*************************
Basically and without thinking it through too much you would have
HV power from the jack running to the collector (the in) of a
transistor.
The emitter (the out) from said transistor would run to to base of another
transistor (resistors would be needed).
The first tranny would be switched by PORTA somehow. This gives the zoning.
Can't remember how PORTA works so I cannot say more now.

All you need then is a power supply through the IR LEDs to the collector
(the in) of the second transistor
As above this is being switched by the 'zoning' transistor.
Connect the emitter to ground and off you go. Again resistors may be needed
to stop the LEDs going pop.
******************END HOW TO**********************
For every tranistor added there will be a degrdation in the signal but we
only have two deep (ad only one switching rapidly) here so should be OK.
Try it and see. Pick fast switching trannys as well. Maybe Dr John could
advise you there. This should be nice and cheap as well. Care in your
choice of components is advisable as 8 LEDs might draw quite a current.

If you were really cautious you might want to opto isolate it but that is
probably another project.

If I have made any glaring errors then point them out to me. If you need a
piccy it will have to wait as I am at work and not working!!!!

Ian B



Original Message:
-----------------
From: andy_powell_is ukha@xxxxxxx
Date: Mon, 27 May 2002 10:41:31 -0000
To: ukha_d@xxxxxxx
Subject: [ukha_d] Re: Electronics Gurus brain required...



Ok, so when I looked at this at first I thought 

"ok, this will provide me with 1 IR output for each zone, if I want
more then I plug each zone into a Xantech IR splitter."

Then I saw the price! ( a 10 way splitter is nearly 80 quid - without 
psu) ... So I got to thinking...

The circuit it clearly simple, so how do I go about making it 
something like an 8 Zone with 8 outputs per zone system?

That's where I stopped :( 

Should I be using relays? From what Dr John was saying I don't want 
to be pluging 64 emitters into Homevisions IR output jack at the back.

I'm wondering if a tweaked version of Ian's relay board is what I'm 
after?? 

Any ideas... (especially Ian :P )

Andy


--- In ukha_d@y..., "andy_powell_is" <ukha@b...> wrote:
> Ok,
> 
> So Keith is busy working on KAT5 (which makes sense) so I decided 
to 
> take another look at the El Cheapo Homevision IR Zone interface 
thing 
> again to see if I could work it out...
> 
> http://groups.yahoo.com/group/ukha_d/files/HVIR.jpg
is what I came 
up 
> with...
> 
> Could one of you electronics Gurus take a look and see if my logic
is 
> correct or if I have totally got the wrong idea...
> 
> I'm expecting 2 things to happen.. the IR emitters to - err emit 
the 
> ir and the LEDs for whichever zones to flash at the same time...
> 
> Thanks,
> 
> Andy



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