Re: Hmevision ir transmitter

["andy_powell_is" <ukha@xxxxxxx>]

Ian,

Thanks for the reply, I should say that I'm just starting out in 
electronics so you'll need to dumb - down any advice :P ...

if you look at:

http://groups.yahoo.com/group/ukha_d/files/Transistor.bmp

You'll basically see the circuit. The general idea is to take the IR 
pulse (which appears to be +5v for on and 0v for off) and output to 
multiple IR LEDs. The obvious things are that:

a) I don't want to go near Homevision until it's tested
b) the current draw from homevision should be as little as possible.

In the end I'm aiming for 8 zones of IR with 8 outputs (3.5mm mono 
jacks into which emmiters can be plugged) for each zone plus 1 LED as 
an indicator for each zone...

Hope this explains a little of what I'm hoping to achieve...

Thanks again,

Andy




--- In ukha_d@y..., "Ian Davidson" <ian@g...> wrote:
> Hi
> 
> I've not been following this thread but I have just drawn out the 
circuit
> you described.
> 
> The BC182 will never conduct because it never has any voltage on 
it. i.e. it
> is either not connected or connect to ground via the switch. The 
bc182 is an
> NPN transistor and requires at least 0.7v between b/e junction to 
conduct.
> If you add a pull up resistor between the base and vcc it should 
work but
> you will need a value high enough to prevent exceeding the base 
current. If
> you tell me exactly what you want to achieve I'll try to be more 
helpful.
> 
> Ian D
> 
> ----- Original Message -----
> From: "andy_powell_is" <ukha@b...>
> To: <ukha_d@y...>
> Sent: Thursday, May 30, 2002 7:59 PM
> Subject: [ukha_d] Re: Hmevision ir transmitter
> 
> 
> >
> > Ian,
> >
> > I'm actually stubling at the first hurdle here...
> >
> > I have :
> >
> > One one breadboard with a 5v supply a BC182, C is connected to
+5v
> > via a resistor, B is connected to Ground (via a push switch) and
E is
> > connected to the B of a 2N2222 on another breadboard with 5v 
supply
> > (spearate from the first one). The C of the 2N2222 is connected
to 2
> > LED's in series with a 220ohm resistor and the E is connected to
the
> > ground of the supply on this board.
> >
> > I expected the LED's to light up - guess what? It does nothing
:(
> >
> > Any ideas???
> >
> > I thought it was the circuit I'd drawn (uploaded to the files
area)
> > before...
> >
> > Andy :(
> >
> >
> >
> >
> >
> > --- In ukha_d@y..., "Ian B" <Ian@M...> wrote:
> > >
> > > > I noticed that you said you were using 3 port pins,
which 
sounds
> > > > better than using 8...
> > >
> > > Andy
> > >
> > > I think Frank has built this round a 3 to 8 decoder which
means
> > only one
> > > zone could be active at any on time. Using all 8 pins of
port A
> > gives you
> > > any combination you want simultaneously.
> > >
> > > Ian B
> >
> >
> >
> > For more information: http://www.automatedhome.co.uk
> > Post message: ukha_d@xxxxxxx
> > Subscribe:  ukha_d-subscribe@xxxxxxx
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> > List owner:  ukha_d-owner@xxxxxxx
> >
> > Your use of Yahoo! Groups is subject to 
http://docs.yahoo.com/info/terms/
> >
> >
> >



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