Re: Hmevision ir transmitter

["andy_powell_is" <ukha@xxxxxxx>]

--- In ukha_d@y..., "Frank Mc Alinden" <armagh@b...>
wrote:
> Andy
>         The best person to
explain these things is off list at the 
moment
> K.D.

Yes, I know, it pains em that he's working hard on the KAT5 box :P

>You are using the transistor basically as a switch,
> switching it on and off rapidly to mimic the ir signal.

Yep, I think I get that part... 

> The ground signal i think you are referring to is supplied by the 
open
> collector output of HomeVision .When someone refers to open 
collector it
> means that the collector is connected to ground when the ouput is 
active.

This is the bit I'm unsure about, from what you are saying I /guess/ 
that what you are telling me is that the IR jack on the back isn't 
pulsing 5v it's making a connection to ground, ie pulsing a circuit 
in that normally the ir jack isn't grounded when ir is sent the 
ground is connected and unconnected very quickly to create the IR 
pulses.

My problem is understanding that if the diagram I did before 
(http://groups.yahoo.com/group/ukha_d/files/Transistor.bmp) 
is 
correct then the transistor would never pass any current because in 
order for HV to send a pulse it must have the ground, but as soon as 
the ground is made on the base of the transistor there is no current, 
and thus the transistor wont pass the current... or have I lost the 
plot entirely?


> Andy  hope this makes sense also i hope to teach myself 
Visual 
Basic as i
> want to learn a high level language so i will have lots of question
s to ask
> you programmer gurus

No problems here Frank, I'll be happy to help where I can..

Andy









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