Re: Re: Hmevision ir transmitter

["Frank Mc Alinden" <armagh@xxxxxxx>]

Hi Ian + Ian
                   
I think i confused myself more than Andy . Anyway its
probably better if only one person advises Andy . I will keep dabbling
with
my idea for transmitting until  i get the bloody thing to work.

Frank Mc
----- Original Message -----
From: "Ian B" <Ian@xxxxxxx>
To: <ukha_d@xxxxxxx>
Sent: Saturday, June 01, 2002 7:15 PM
Subject: RE: [ukha_d] Re: Hmevision ir transmitter


> Good catch on the design. It was late last night after a fun time with
the
> new baby.
>
> I agree about the recent post of messages being confusing to say
the
least.
> Your design is better than mine and I have set it up as a pdf for
simplicity
> and recording at my end. I am still learning after all.
>
> Both of the designs achieve the same aim of zoned output controlled by
one
> of HV ports. I thought some of the previous discussion was going off
track
a
> bit and all that negative logic was horrid.
>
> As soon as I find out the path on the web server to my web site I
will
post
> the pdf's there but in the mean time here is another apology and
another
4k
> attachment. All down to playing primary domain controller removal and
it
> deleted my accounts as well - dohh.
>
> Andy - sorry if all this is confusing and shout if anything (apart
from
> everything, oh well, that as well) is unclear.
>
> A quick lesson on transistors!!
> These other transistors we are talking about with the arrow going into
the
> base rather that out of it operate in a different way. You can think
of
the
> ones where the arrow goes out of the base BC182 etc. as having the
turning
> on power flow into the base and out of the emitter. The other ones
like a
> BC327 etc. have the turning on power flow into the collector and OUT
of
the
> base. This is very simplistic and of course current is negligible
when
> referring to the base. In both types the main flow of current when
the
> device is active is from collector to base. Hopefully this makes
sense
(and
> I am correct).
>
> Ian B
>
> >-----Original Message-----
> >From: Ian Davidson [mailto:ian@xxxxxxx]
> >Sent: 01 June 2002 09:32
> >To: ukha_d@xxxxxxx
> >Subject: Re: [ukha_d] Re: Hmevision ir transmitter
> >
> >
> >Hi Ian B
> >
> >If you wish to do it the way you suggest an easier circuit would
be
> >
> >http://galeforce9.dnsalias.org/dsc0_0069.jpg
> >
> >A few less components and current draw off the ports of HV
still
> >well within
> >the limits.
> >
> >As I've said I don't have HV (maybe one day!) but if the members
that do
> >have it and require the IR say which port they would prefer to use
and
the
> >maximum ratings they would want to control then I'm sure we could
design
a
> >circuit with minimum components that most people even with
minimum
> >electronics experience could build.
> >
> >At the moment things keep changing so I think any designs should
be
shelved
> >until a common goal is reached as to what is required, if not the
poor
> >people trying to understand basic electronics from that last batch
of
> >messages will be frightened off for life !!!
> >
> >Ian D
> >
> >----- Original Message -----
> >From: "Ian B" <Ian@xxxxxxx>
> >To: <ukha_d@xxxxxxx>
> >Sent: Saturday, June 01, 2002 12:46 AM
> >Subject: RE: [ukha_d] Re: Hmevision ir transmitter
> >
> >
> >> Your circuit looks like I had in mind back in year dot. I
have sat down
> >and
> >> had a think about this and we have been leading you up the
garden path
a
> >> bit. Fun trip though wasn't it. Anyway, here are my
thoughts..........
> >>
> >> I have attached (for my sins) a very small pdf with the
circuit (not
> >quite)
> >> as I saw it in my minds eye.  Things have changed a bit
and the TR1
codes
> >> etc. no longer refer to the same transistors so pay
attention. After
some
> >> (considerable) thought I figure the best way to do this is
use Port C
in
> >> OUTPUT mode. According to the specs it can drive TTL and
CMOS. This
means
> >> LED's so enough current for us.
> >>
> >> In off state PortC must be all zeros and we don't care what
the IR out
is
> >> doing. In this state TR2 is not conducting so the LED's are
never on.
> >>
> >> Right, from the left ($^%!) we have a pull up resistor
connecting to a
> >> tranny TR1. When HV transmits IR the base is pulled low and
the tranny
> >stops
> >> conducting. I assume here that HV switches the ground. This
in turn
sends
> >> the voltage through TR2 high. This is where the clever zoning
bit is.
If
> >> PortC pin x is high it drives the tranny TR2 base and the
voltage
reaches
> >> TR3 - zone ON. If however the PortC pin x was low the voltage
would
never
> >> reach TR3 and nothing happens. As soon as the voltage reaches
TR3 it
> >> conducts and the LED's come on! Voila...... Obviously the
LED's on the
> >right
> >> would be as many as you want i.e. 8 in your case.
> >>
> >> Well, that's the theory anyway.
> >>
> >> There may be a better way round this but it is late and I am
tired
> >(excuses
> >> excuses).
> >>
> >> I hope this is helpful and that I have got it somewhere near
correct.
> >>
> >> Off for a midnight snack, have fun. Let me know if the
diagram and text
> >are
> >> rubbish.
> >>
> >> Ian B
> >>
> >> p.s. you owe me one for making me think!! ;-))
> >>
> >> >-----Original Message-----
> >> >From: andy_powell_is [mailto:ukha@xxxxxxx]
> >> >Sent: 31 May 2002 20:25
> >> >To: ukha_d@xxxxxxx
> >> >Subject: [ukha_d] Re: Hmevision ir transmitter
> >> >
> >> >
> >> >
> >> >Ok, I'll try again.... (this is an abridged version!)
> >> >
> >> >I've got the original circuit working.. it was the 2N2222
that was..
> >> >err dead.. replaced it and it's all ok now...
> >> >
> >> >The circuit now consists of the diagram at
> >> >http://www.automated.it/homevision/HVIR2.jpg
but with the bit that
> >> >says Homevision port removed...
> >> >
> >> >
> >> >> I think I've read the relevant messages. IF I've
read them right
> >> >
> >> >There was a sudden rush of them, mainly due to my lack
of
> >> >intelligence :P
> >> >
> >> >> port a o/p is via a PNP which means it will source
the o/p and give
> >> >a +volts
> >> >> supply.
> >> >
> >> >I've used the phrase before, and I'm going to use it
again, err,
> >> >chicken soup...
> >> >
> >> >> This lunch I built up a simple circuit details are
here:
> >> >> http://galeforce9.dnsalias.org/dsc0_0064.jpg
> >> >
> >> >Thanks, I've saved them for reference...
> >> >
> >> >> You only need the one transistor. It is ZTX651 I had
on the bench
> >> >at work.
> >> >
> >> >Awwww, I have a big bag of 2N2222's and BC182's :(
> >> >
> >> >
> >> >> It will handling up to 2A and does not require any
form of
> >> >heatsink. It is
> >> >
> >> >I've put a 1k resistor in from the power supply to the
collector of
> >> >the first transistor and according to the Circuit maker
I'm pulling
> >> >2.995ma (the 1k resistor appears to drop the current from
32.5ma to
> >> >2.995ma, apparently)... is that a problem? am I going to
upset
> >> >homevision by putting that resistor in there? it still
works on the
> >> >breadboard...
> >> >
> >> >Bearing in mind that this is only 1/8 of the circuit, if
I add 7 more
> >> >am I going to pull too much current?
> >> >
> >> >> an e-line transistor and has a very low on
resistance. It will only
> >> >take
> >> >> about 1mA of current to drive it from homevision. If
the led's you
> >> >use are
> >> >> 20mA devices then each transistor will drive 100 of
them. If this
> >> >is OTT
> >> >
> >> >Phoaaaarrrrr!! 8 zones of 100 emitters :P
> >> >
> >> >> The circuit is wired just to show it working ie the
10K resistor to
> >> >the base
> >> >> is connected to the 5V rail to simulate a 5v o/p
from HV.
> >> >
> >> >So the HV port A supplies +5v too?? This is the bit I'm
really unsure
> >> >of... should I connect the base of the first emitter to
Homevisions A
> >> >ports via a 10k resistor (one for each A port ie one for
A1, one for
> >> >A2..etc)?
> >> >
> >> >
> >> >> If you drop me your address Andy I'll stick it in
the post and you
> >> >can
> >> >> experiment with it. (It is no good to me !)
> >> >
> >> >I'll email it privately... :D
> >> >
> >> >
> >> >>
> >> >> In answer to an earlier question you are correct
that for current
> >> >to flow it
> >> >> needs to complete a circuit. When voltage is applied
to the base of
> >> >a
> >> >> transistor it flows through the base emitter
junction of the
> >> >transistor to
> >> >> ground.
> >> >
> >> >You've lost me with this. Where is this? is it that it
flows (in the
> >> >circuit at the url above) to the second transistor via
it's emitter
> >> >and off to the seond and then to the emitter of that and
hence to
> >> >ground?
> >> >
> >> >
> >> >> I hope I've explained things ok, I'm not the best
teacher, but if
> >> >you are
> >> >> unsure just ask.
> >> >
> >> >You're doing pretty well if you ask me...
> >> >
> >> >> Again so as not to offend the list if ANYONE wants
this topic off
> >> >list just
> >> >> say and it will be.
> >> >
> >> >I did ask and the suggestion was that quite a few people
are
> >> >interested, not only that but that this was one of the
few on topic
> >> >threads... :O
> >> >
> >> >Thanks for all your help
> >> >
> >> >
> >> >Andy
> >> >
> >> >
> >> >
> >> >For more information: http://www.automatedhome.co.uk
> >> >Post message: ukha_d@xxxxxxx
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> >> >List owner:  ukha_d-owner@xxxxxxx
> >> >
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> > >
> > >
> >
> >
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>
>
>
>
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