[Arm-netbook] capacitive touchpanels

[luke.leighton]

http://electronics.howstuffworks.com/iphone2.htm

this is fascinating.  and... well... kinda necesary to investigate.  i
found out that a decent 7in tablet capacitive panel (5T) is around $22
to $24.  this is mad prices.  one that has a lot less sensor lines can
be had *WITHOUT* an on-board controller IC can be had for around $11.

*but* - the problem with doing that according to wikipedia is stray
capacitance: http://en.wikipedia.org/wiki/Capacitive_sensing#Circuit_design

however, given that the price of the controller ICs is absolutely mad
- i'm seeing prices of $4 (!!) - it's just... i can't bring myself to
justify it sooooo, the idea is to use a 100-pin STM32F.  15 "scan"
lines (across the horizontal), and 10 "sensor" lines (going down), i
feel reasonably confident that this is doable, although, obviously,
i'm going to have to check!

what fun, eh?  no proprietary ICs - just use a single controller, do
it all as free software :)

l.