[sdiy] 8 wire touchscreen

[Craig Critchley]

Here's a tech docs page at 3M:
http://www.3m.com/3MTouchSystems/downloads/tecdoc.jhtml

Near the bottom of the page is this PDF:
http://www.3m.com/3MTouchSystems/downloads/PDFs/18172sc3rev4WEB.pdf

It's docs on a touchscreen evaluation board.  There's a pinout and pin
description of 8-wire touchscreens in this documents.  It looks like there's
4 lines to drive voltages along the edges and 4 sense lines, one on each
edge.

Touchscreens are fun; I recently built an analog controller out of a surplus
5-wire.  How large is the one you salvaged?  The 3M docs say the 8-wires
tend to be the larger ones.

                    ...Craig

----- Original Message -----
From: "Paul Maddox (QinetiQ)" <P.Maddox at signal.qinetiq.com>
To: <synth-diy at dropmix.xs4all.nl>
Sent: Monday, July 29, 2002 2:00 AM
Subject: [sdiy] 8 wire touchscreen


Dear all,

 for one of my Projects (Tempest,
http://www.modulus.wavesynth.com/projects/projects.htm )
I'm useing a touch screen.
The one I salvaged has 8 wires (not the usual 4).. does anyone have any
links showing what the hell to do with the extra 4 wires :-)

Initially I thought they would be ground screening or something, but they're
not..
Ive speant about 2 hours trying to figure out the wiring (with my DVM and
touching the screen) only to get more and more confused as time goes by.
Ive got my screen driver going (I must get a digicam to take some pictures)
on an FPGA driving one of these (EL640.400-CB1)
http://www.planar.com/products/el.asp so now to get the touch screen working
in front of it....

Many thanks
Paul Maddox