Re: Led-switch Alternative

["Frank Mc Alinden" <fmcalind@xxxxxxxxxxxxxx>]

Hi Ian

> I am also experimenting with these for some touch buttons I am
building. I
> am using the QT160 parts (6 buttons), which ones are you looking at?

Yes i recall you mentioned the 6 button unit before ...the ones i have are
1
button qt113d...but i would really like to try the 6 button.....Where did
you source yours from....?


> If you are going to have your LED's in the same plate you are using
for
> touch sensing you will need to capacitively decouple every component
of
> the LED i.e. one cap before the LED, one after it and another after
the
> resistor

Oh Bugger!!......I have only bench tested the Qt113d , havent tried it with
the leds...I might try and used sheilded wire for the touch probe....

>I also asked Quantum about dimming using PWM for LED's in this
> situation and they did not know as they had never tried it. The
potential
> problem being the continual switching of the LED on and off might
upset
> the capacitance field sensing circuitry.

Will find out very shortly if its going to be an issue..........;-)


> From what I can see it would not be too difficult to make a one or up
to
> six button switch plate and give it the driving logic to switch low
> voltage coils in relays. These relays could then control the LD11
units as
> Gareth would like to do.

True but ..the output would need buffered as it doesnt seem to drive leds
and would need some intelligence to dim / brighten the leds

Frank



----- Original Message -----
From: <ian.bird@xxxxxxx>
To: <ukha_d@xxxxxxx>
Sent: Sunday, March 20, 2005 5:54 AM
Subject: Re: [ukha_d] Led-switch Alternative


>
> Hi Frank
>
> I am also experimenting with these for some touch buttons I am
building. I
> am using the QT160 parts (6 buttons), which ones are you looking at?
>
> If you are going to have your LED's in the same plate you are using
for
> touch sensing you will need to capacitively decouple every component
of
> the LED i.e. one cap before the LED, one after it and another after
the
> resistor. I also asked Quantum about dimming using PWM for LED's in
this
> situation and they did not know as they had never tried it. The
potential
> problem being the continual switching of the LED on and off might
upset
> the capacitance field sensing circuitry. I guess the alternative would
be
> something like a digital pot but I don't know whether that would work
or
> not.
>
> From what I can see it would not be too difficult to make a one or up
to
> six button switch plate and give it the driving logic to switch low
> voltage coils in relays. These relays could then control the LD11
units as
> Gareth would like to do.
>
> Ian
>
>
>
>
>
>
>
> "Frank Mc Alinden" <fmcalind@xxxxxxx>
> 19/03/2005 05:51
> Please respond to ukha_d
>
>
>         To:     <ukha_d@xxxxxxx>
>         cc:     (bcc: Ian Bird/CV/Novartis)
>         Subject:        Re: [ukha_d] Led-switch Alternative
>
>
>
> Hi Gareth
>
> > And mebe we could figure out how to use these to control a 240v
signal
> > from an LD11 ?
>
>   I assume you mean the manual contacts on the LD11
..??......Currently if
> i
> need to operate dry contacts to switch 240xv  i would use  xPL-DMX 
since
> i
> have the Dmx controller and relay board....and xPL has a Dmx
plugin.....im
> sure the something similiar applies to xAP and others....
> No Cbus .........????
>
> Frank
>
>
> ----- Original Message -----
> From: "Gareth Cook" <g@xxxxxxx>
> To: <ukha_d@xxxxxxx>
> Sent: Saturday, March 19, 2005 6:23 PM
> Subject: Fw: [ukha_d] Led-switch Alternative
>
>
> >
> > And mebe we could figure out how to use these to control a 240v
signal
> > from an LD11 ?
> >
> > G.
> >
>
>
>
>
>
>
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