On Sun, 20 Mar 2011 19:11:07 +0000 Folderol <folderol@xxxxxxxxx> wrote: > On Sun, 20 Mar 2011 18:52:24 +0000 > andy baxter <andy@xxxxxxxxxxxxxxxxxxxxxxxxxxx> wrote: > > <snip> > > > The only thing I found problematic in his design wasn't to do with > > usability but the expense (and also physical bulk) of having to use a > > high end audio interface as part of the electronics. This put me off > > building one myself, so I am thinking of having a go at a very similar > > design but using a resistive rather than capacitive pressure sensing > > technique. I.e. basically the same design but using a sheet of carbon or > > metal loaded conductive rubber and measuring the resistance changes when > > you scan through the matrix. If this works, it will hopefully produce > > similar results but with much simpler electronics and firmware. > > > > andy > > This is vastly overcomplicated. Once you understand the concept itself (which > really is good), a set of dedicated oscillators and detectors (tuned > amplifiers+A/D converters) would by much simpler, smaller and reliable. I would > then be inclined to try to embed the electronics in the device itself, and bump > up the operating frequency as much a possible to improve the response time of > the detectors. Answering my own post... I mean the original concept using the audio interface is overcomplicated. The resistive idea has the merit of dramatic simplification but I wonder at the consistency of the resistive elements and whether you would get a (reasonably) linear output of if it would tend to behave more like a low quality switch. -- Will J Godfrey http://www.musically.me.uk Say you have a poem and I have a tune. Exchange them and we can both have a poem, a tune, and a song. _______________________________________________ Linux-audio-user mailing list Linux-audio-user@xxxxxxxxxxxxxxxxxxxx http://lists.linuxaudio.org/listinfo/linux-audio-user
