AW: Re: Force Sensing Pad (again)

[Haible_Juergen#Tel2743]

>I tired this a few years ago but found that even after a few days, the foam
>became permanently squished, forcing (no pun etc...) me to change it every
>week!

That's the reason why I didn't even try it, so far. Maybe amongst all the
different materials there is one that doesn't loose its shape? Gene,
You said something about a special kind of foam ... can You tell us
more?

>I eventually ripped off ARP's design, although not exactly *force* 
sensitive,
>all that is required to vary the resistace is to rock you finger forward on
>the pad.
>It consisted of the track from a 100k lin *slider* pot, and a piece of
>carbon fiber material suspended (that was the hard part, but I work for a

The most impressive design I have seen is built into the Synton Syrinx.
It works with capacitive coupling (but I didn't figure out the electronics)
and uses 3 pieces of PCB board fixed together in a special way.
The three boards form a sandwich structure, with the lower board
fixed to the Synth's front panel, a much smaller board fixed to the first
one, and then a full-sized 3rd one. Now You can press on top of the
sandwich, and the 3rd pcb is bent over the 2nd and comes closer to the 1st.
The 3rd one has a slit, effectively dividing it into two halfs, so You can 
press
each of the "fingers" independently for pitch bend and modulation.
Well, it's capacitive and will probably require a HF oscillator, but it is
really a very nice controller.
Maybe we could combine the two methods: stuff a thin layer of conductive
foam between the Syrinx-like controller, making it resistive, and releasing
the foam from its duty to fully restore its originally shape?

JH.


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    Air (C) or  Foam (R)                 ========  PCB 2
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