RE: Electronics help with IR TX-RX

["Graham Howe" <graham@xxxxxxx>]

Thanks for that James, that could have been one of my problems but I have
now solved everything. At the risk of embarassing myself still further,
here
is what went wrong.

First I did somehow manage to blow a TSOP on the board that I had glued
into
the PIR.
I opened the PIR (having first deleted the zone from Comfort to avoid
tamper
alarm) and took out the board.
In the office I tried the board on a battery and with a meter and confirmed
the TSOP was dead.
I then tried another TSOP on the battery and it worked, tried it on Comfort
and it worked, tried it in conjunction with the transmitter and got
nothing.
Several more test confirmed the transmitter was dead (I haven't worked out
which component yet) with the LED on regardless of signal.
I then tried another transmitter with my working receiver on the battery
and
everything was fine.
I then tried the two direct from a Comfort output and everything was fine
(shows I was talking complete crap about a problem with the voltage).
So full of enthusiasm I connected the receiver back onto the PIR (but
didn't
glue it or close up the PIR at this point) and connected the transmitter
via
the Krone blocks in the office.
The LED on the transmitter was on continuously (and if anyone has worked
out
why at this point without reading the next line, then I will buy them a
pint
and bow to their supperior intellect).
I went back downstairs, about to trash the whole idea of putting IR
receivers inside PIRs, but as soon as I looked at the open PIR with the
receiver dangling by the wires, I realised my mistake, the LED on the PIR
was on continuously because the case had been opened, my RX-TX pair were
correctly relaying the signal from this back up to the office!
As soon as I disconnected the LED in the PIR, everything worked fine.

Graham

-----Original Message-----
From: James Hoye [mailto:james.hoye@xxxxxxx]
Sent: 15 May 2001 22:00
To: ukha_d@xxxxxxx
Subject: RE: [ukha_d] Electronics help with IR TX-RX


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---------------------------------------------------------------
Where are you deriving the power (12v) for the TX board from?  Just
thinking
that the signal wire is going to be relative to Comfort's 0v - and if
you're
using another power source for the TX board.....

Just a thought - Keith will probably shed more light....

James H

> -----Original Message-----
> From: Graham Howe [mailto:graham@xxxxxxx]
> Sent: Tuesday, May 15, 2001 9:53 PM
> To: ukha_d@xxxxxxx
> Subject: RE: [ukha_d] Electronics help with IR TX-RX
>
>
> I have the Zener diode and resistor combination in place and that
works
> fine, what seems to be the problem is that the signal generated by
this
> (0.5V drop) is not interpreted properly by the transmitter unit when
the
> high voltage is applied. As I said the receiver bit seems to work
> OK (I can
> see the voltage drop on the signal wire) but the signal does give
> rise to a
> corresponding flashing of the LED (and IR LED) on the transmitter unit
if
> the higher voltage is involved.
>
> Graham
>
>  -----Original Message-----
> From: 	James Hoye [mailto:james.hoye@xxxxxxx]
> Sent:	15 May 2001 20:45
> To:	ukha_d@xxxxxxx
> Subject:	RE: [ukha_d] Electronics help with IR TX-RX
>
> This email was delivered to you by The Free Internet,
> a Business Online Group company. http://www.thefreeinternet.net
> ---------------------------------------------------------------
> The TSOPs work at 5v and as such need some sort of regulation -
> either using
> a 39p voltage regulator from M***** or the combination of a 5.1v
> Zener diode
> and a resistor.  Ian B's PCBs utilise the Zener/resistor - I'm sure he
can
> provide you with the circuit details.
>
> I have a couple of spare TSOPs, and I'm sure Keith has quite a few
left.
>
> James H
>
> > -----Original Message-----
> > From: Graham Howe [mailto:graham@xxxxxxx]
> > Sent: Tuesday, May 15, 2001 7:20 PM
> > To: UKHA List (E-mail)
> > Subject: [ukha_d] Electronics help with IR TX-RX
> >
> >
> > As many of you know, I eventually managed to put together some
> working IR
> > transmitters and receivers with help from several on the list and
> > despite my
> > non-existent electronics knowledge. However I now have a
> problem, the kit
> > works fine when I use a 12V battery and connect both TX and RX
> to it (with
> > an additional wire between them for the signal). I am currently
in the
> > process of installing Comfort and so drilled a little hole in one
of the
> > PIRs and inserted an IR RX unit. I connected the 12V and 0V from
> > the PIR to
> > the unit and used a spare wire in the CAT5 cable for the signal.
Then I
> > connected up the TX unit via Krone blocks and patch panel and it
didn't
> > work. After I finished cursing myself for not testing the set up
before
> > gluing the RX inside the PIR I started to investigate. After
> much probing
> > with a voltmeter, I discovered that the 12V output from Comfort
> > was actually
> > 13.8V and that when fed with this voltage the kit wouldn't work,
> > in fact the
> > TS1308 (is that the right code? If not it is the things Keith
> was selling)
> > seemed to die after a while at this voltage (I now have 2 dead
> > ones). I then
> > tried having just the RX unit fed by Comfort and the TX fed by
> > the battery,
> > this didn't work either, even though I could see the 0.5V drop in
the
> > trigger wire when IR was received. At this point I started
> thinking that I
> > was well and truly out of my depth, so I started guessing what
might be
> > wrong. Here are my thoughts:
> >
> > The RX unit will operate correctly for at least a limited time
when
> > connected to the 13.8V, the trigger wire shows 5V which drops
> to 4.5V when
> > IR is received.
> >
> > The TX unit does not appear to like the higher voltage at all and
> > certainly
> > doesn't react correctly to the trigger when the higher voltage
> is applied
> > (could it be that the 0.5V drop is no longer sufficient to do
> the 'magic'.
> >
> > Both a RX and a TX unit appear to have been killed during my
> experiments,
> > possibly as a result of the high voltage.
> >
> > It seems I have two options, either use an alternative power
> > supply that is
> > closer to 12V and therefore put up with less convenient wiring
inside my
> > PIRs. Or use some sort of electronic trickery (possibly a
resistor?) to
> > reduce the voltage supplied from Comfort (after all the Comfort
> > outputs are
> > labeled 12V).
> >
> > Please can one of you electronic geniuses give me some advice,
> > with the DDAR
> > price increase this is turning out to be a very unsuccessful day!
> >
> > Graham
> >
> >
> >
> >
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> >
> >
> >
>
>
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