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Sender: nathan AT bonesofwrath DOT com
Date: Thu, 12 Jun 2014 13:51:01 -0400
Message-ID: <CAHeNMgRL7=M3iaq8=dxmhoVBF+zpi1F50Dnu-=+prNaG0u4qVg@mail.gmail.com>
Subject: [geda-user] large area xy capacitive touch
From: Nathan Stewart <therealnathanstewart AT gmail DOT com>
To: "geda-user AT delorie DOT com" <geda-user AT delorie DOT com>
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Reply-To: geda-user AT delorie DOT com

I'm sketching a design that has a large x-y capacitive sensing area -
like 5cm x 50cm ish. This presents a couple problems for the hobbiest.
1) It's larger than most of the fab houses allow. 2) Since it's an x-y
sensor, I think I'd either want a 4-layer board (in order to get two
closely spaced layers on the top side), or use a flexible 2-layer PCB
for the sensing area. Or 3) I could do it in chunks of identical
sensing boards.

4 layers, flexible, and large are all major cost drivers. If I do it
with multiple boards - I need to be able to interpolate between
segments on separate boards, that seems like it's opening a major can
of worms with a capacitive sensor.  Multi-touch is also a requirement.
Approach velocity is highly desirable if those impact the approach.

How would you go about this? I'm currently thinking multiple boards
with buffering as needed is probably going to be the best approach.
Thoughts?