this question is a little long-winded, so please bear with me....
I recently hacked a cheap resistive touchpanel; the implementation was unsuccessful but I was intrigued by the practicalities of pulsing each axis to get continuous X-Y location data - each axis is rapidly switched between a read function and a 5v function. In the end the noisy data prevented further use.
I am currently working on a 5x3 grid of DIY force sensors, which works well, giving me 15 discrete touch locations and Z-axis force data:
Following an idea by Randy Jones, who successfully implemented a multitouch FSR matrix:
I am considering extending the grid into an 8x8 matrix, which will give me 64 discrete locations, Z-axis force and greater opportunity for interpolation across the entire matrix.
My question is: can I 'hijack' the rapid switching idea from the resistive touchpanel (power the X axis, read the Y, then power the Y axis and read the X?) in my DIY FSR matrix.
There are 2 simple diagrams explaining my concept, here:http://www.docstoc.com/docs/90785897/DIY-FSR-matrix
(I'm having trouble attaching/uploading picture files here).
My initial concept was for 8 strips of copper fabric (all connected to 5v) laid out in rows, then a layer of velostat, then 8 columns of copper fabric connected to the read inputs via pulldown resistors. It occured to me that I could only get ONE axis reading for this circuit (as depicted in the first diagram above); but would it be possible to get discrete X-Y touch location by rapidly alternating reading and powering to the circuit? I could easily build and code for this, but what I don't know is, how would I interpolate between reading X axis and Y axis to give me one reading (for each of the 4 points in the second diagram above)?
Thanks for bearing with me