RE: Can some kind electronics bod help?

["Shane Harrison" <shane.harrison@xxxxxxx>]

See comments below

> -----Original Message-----
> From: Paul S. Gale [mailto:groups@xxxxxxx] 
> Sent: Wednesday, 5 February 2003 1:36 a.m.
> To: ukha_d@xxxxxxx
> Subject: RE: [ukha_d] Can some kind electronics bod help?
>  
> 
> Yes - it seems that the Kustom amp is based on 5V IR signals 
> - how could I tell for sure without a scope? Would a digital 
> multimeter give an accurate enough reading on the IR lines? 
> (or should the IR output from the wall controller be the same 
> voltage as the supply voltage?)

If you are lucky and the Kustom input has an internal pullup
(essentially a resistor to the power rail) then the input will sit at
the power rail voltage when no signal is applied to it.  If it has
no
internal pullup then pretty hard to tell with out scoping the the
existing IR signal being fed in.
> 
>  
> 
> As both Kustom and HV seem to use 5V, should I just try it 
> without any electronics? Given they're both 5V could I do any 
> damage? Is all this talk of transistors not needed as both 
> systems run at 5V?
If the HV expansion board is open collector as Frank thinks, then you
can't really do any damage if you connect them together.  However
with
open collector outputs (essentially it is a switch to ground only,
either the output is grounded or not grounded (floating)) you need
something to "pull" the signal up to a positive voltage when the
open
collector "switch" is not switched to ground.  This can be
an external
resistor (say 10K) or if you are lucky the Kustom has internal pullups
as discussed above.

HTH (and makes sense)

Shane



http://www.automatedhome.co.uk
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