This afternoon I decided to test my theory that it should be possible to multiplex a grid of discrete FSRs, using only a small number of analogue read pins on the Arduino. The implementation borrows ideas from resistive touch panel hacking and vaguely uses the idea of multiplexing.
Rows of electrodes (tied to ground, and read) are overlaid with columns of powered electrodes, each of which is set HIGH in turn, scanning across the grid. A 5 x 5 grid, for example, allows reading of 25 discrete and dynamic contact points.
Read more here:
Video demos here:
Todo: secure electrodes, and resistive film, overlay a silicone rubber or foam surface to enhance tactility.