Semi-OT: Touch sensors

[Colin McGregor]

--- Tyler Aviss <tjaviss-Re5JQEeQqe8AvxtiuMwx3w at public.gmane.org> wrote:
> Hello All,
> 
> One of my ongoing projects has been to wire up a few
> mini-ITX boards
> as "media control" PC's for around the house.
> Basically the idea is
> that the board connects to the main household server
> via PXE-boot,
> NFS-mount, etc. It will be attached to a lilliput
> touchscreen (for
> which the linux drivers work nicely, BTW).
> 
> Now the end-plan for this is to move the touchscreen
> into a picture
> frame, with the rest of the wiring in-wall or just
> otherwise somehow
> safely hidden. What I would like to do is have a
> touch-sensor attached
> to either the picture frame or perhaps a little
> plaque attached to a
> wooden frame. Like a touch-lamp, the sensor would
> then turn on the
> screen. Depending on how fast I can get my boot-time
> going with
> openbios and "sleep" modes, the motherboard...
> although I may just opt
> to leave this on 90% of the time since via boards
> consume very little
> power.
> 
> Anyhow, feel free to critique the idea as a whole,
> but my main
> question at this point is:
> where do I find the equipment needed to make a
> touch-sensitive metal
> surface for the frame/plaque.
> 
> Any ideas?

I'm not quite sure what your goal is here. Simple
on/off control or something a bit more complex.

For simple on/off, and a metal plaque your talking 
the fodder of umpteen hundreds of introductory
electronics books / magazines. 

For a level up from that and any surface, a number of
years ago I read a construction article in a home
automation magazine that had a small LCD module that
sort of did a touch screen. What they did was mount a
set of infrared LEDs and light sensors in pairs around
the LCD module. Fingertip interrupting the beam told
the automation system that the display was being
touched and about over which area of the display was
being touched. A bit of menu software and presto a
home control system by fingertip. One point in the
above that I recall them putting emphasis on was you
want the light sensors at the top and the light
sources at the bottom (to reduce false triggers by
sunlight etc..

For a level above this, I'm not sure ... gut the likes
of a Palm Pilot?

Colin McGregor
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