next up:
velostat conductive film.
http://www.blockemf.com/catalog/product ... ts_id=5247
i read about this from here:
http://www.freepatentsonline.com/4296406.html
The present invention switch comprises a pair of electrodes separated by resilient resistive material which changes resistance several orders of magnitude in response to light pressure. Sensing and amplifying means are provided to detect a predetermined change in resistance. An array of a plurality of such switches may be arranged in a switching matrix to provide any desired form of switch controls or a keyboard for numerous electronic applications.
and later:
The pads 11 and 12, as will be explained hereinafter, may be etched foil printed circuits having a conductive-resistive material which displays a low resistance when little or light pressure is applied and displays a very high resistance when no pressure is applied...Overlying the conductive-resistive material 14 is a layer of conductive material such as copper foil 15 which may be attached to the push-button 16 comprising an insulative material.
The conductive-resistive material is preferrably a plastic which is impregnated with carbon black or a conductive carbon and is non-corrosive to prevent deposits on or oxidation of the copper foil material 11, 12 and 15. Such a material is available from Minnesota Mining and Manufacturing Company (3M Company) under trade name of VELOSTAT (TM). VELOSTAT material may be purchased in the form of plastic sheet approximately 4 mils thick designated as VELOSTAT (TM) type 1704 which is an ethylene vinyl acetate (EVA) modified polyethylene with carbon black filler.
the good news: this stuff is only 1.95!
the bad news: i have to wait another week for it to arrive.
however, this stuff looks promising.