Re: Hmevision ir transmitter

["andy_powell_is" <ukha@xxxxxxx>]

Ian,

Didn't work :( no LED cam on

Andy


--- In ukha_d@y..., "Ian Davidson" <ian@g...> wrote:
> Ok Andy here goes....
> 
> If the circuit is as the diagram in the files area then by biasing
the first
> transistor the led's should light.
> 
> To try this connect say a 10K Ohm resistor from the +5V rail to the
base of
> the BC182.(TR1)
> 
> If you think of this as a switch which will now turn on allowing 
the voltage
> to reach the base of TR2. This will then do the same. So current 
will then
> flow through the LED's through TR2 to complete the circuit.
> 
> Let me know if that works ?
> 
> If it does we may be able to simplify this a little before you 
build the
> rest up.
> 
> Ian D
> 
> 
> 
> ----- Original Message -----
> From: "andy_powell_is" <ukha@b...>
> To: <ukha_d@y...>
> Sent: Thursday, May 30, 2002 10:09 PM
> Subject: [ukha_d] Re: Hmevision ir transmitter
> 
> 
> > --- In ukha_d@y..., "Ian Davidson" <ian@g...>
wrote:
> > > Hi Andy
> > >
> > > Ok no problems, we will get you sorted.
> >
> > Thanks Ian :D
> >
> >
> > > Firstly I do not have homevision and I could do with knowing
the
> > following
> > > if you or others on the list know or could point me to the
tech
> > spec:-
> > >
> > > firstly what sort of o/p does HV produce, is it open
collector ?
> >
> > Yes, "Port A of Homevision provides open collector
terminals"
> >
> >
> > > Does it have any internal pull up resistors ?
> > >
> > > If it does have internal pullups then your circuit may
well
> > function but not
> > > by just fitting a switch to the base of TR1.
> >
> > I don't know the answer to this one :( but looking at
> > http://www.csi3.com/hv_p2.htm near
the bottom, there is a table. 
For
> > the ports B and C it says pulled up, for port A it does not 
mention
> > it ... at a guess, based on that I'd say no... but I don't know
for
> > sure...
> >
> >
> > > Do you need the LED's on when the port o/p is low or when it
is
> > high ?
> >
> > From what I remember Keith was saying that you set the port low
to
> > complete the circuit where +5 is provided by the IR jack and the
port
> > on Homevision provides the ground. So, the LED should come on
when
> > it's low (and an IR pulse is sent)
> >
> > >
> > > If we can find out these details then I'll try to explain
how to
> > test it, or
> > > if not what to change. If all else fails I'll build you a
single
> > channel
> > > unit and then all you would need is to copy it.
> >
> > That would be nice, but it would be better for my skills if I
could
> > work with you to get the final result. If all else fails I'll
gladly
> > take you up on the offer..
> >
> >
> > > Not sure if any one else on the list needs the info but if
not 
your
> > more
> > > that welcome to take the mails off list and send to me
direct, 
I'll
> > leave it
> > > up to you.
> >
> > I think that if this ever gets to work :P quite a few people 
would be
> > interested in it.... so perhaps for the moment we should keep it
on
> > list...
> >
> > Thanks again for your replies..
> >
> > Andy
> >
> >
> >
> > For more information: http://www.automatedhome.co.uk
> > Post message: ukha_d@xxxxxxx
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> >
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> >
> >
> >
> >



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