[sdiy] Touch Controllers

[James Husted]

I made a ribbon controller a couple of years ago using 1/2 audio recording
tape stretched over bare PCB copper. The DC was applied to the PCB and read
from the tape. Very crude and the tape had to be replaced often, but it was
VERY cheap to make.
-James

On 1/20/03 2:54 PM, "The Proteus" <proteus at ugwarehouse.org> wrote:

> Scott,
> 
> Originally, ribbon controllers IIRC were a filament of
> grounded wire put over a strip of resistive material. Wherever you touched
> created a basic potentiometer, and also gave you a similar tactile
> response to that of "tapping" a guitar. I've never worked with older
> units, but I did have experience while working on E-Mu's XL-7.
> Nowadays, touch strips are either re-designed from the ground up
> (as in the case of the Kurzweil touch strip), or they're bought from the
> same companies that make trackpads and similar substrates. I've seen
> products used from Interlink Electronics (www.interlinkelec.com) to create
> both resistive strips and touch pads for drum machines. Also, another
> popular domestic source is Spectra Symbol corporation
> (www.spectrasymbol.com) for resistive elements like pitch ribbons. These
> are primarily resistive touch-strips, other companies make capacitive as
> well as optical strips.
> One really cool technology I was exposed to was the tactex pad
> from tactex controls. It's basically a mesh of fiber-optic cable with a
> urethane pad on top of it. There's an emission matrix and a scanning
> matrix that not only can sense x/y position, but also pressure applied to
> the pad as well. This is better in one major way for musical instruments:
> You can actually have multiple fingers down on the element at the same
> time, and it will read multiple points on the element. Polyphonic trigger
> control, assigning different instruments to different areas of the pad,
> all are possible with this.
> So, this is more of an overview of touch-pad technology, which all
> have applicaiton on pitch ribbons. That's all I've got that would be
> useful for the DIY crowd at the moment... most of the other sources I know
> have too high of a minimum order quantity, or NRE costs that would be
> prohibitive for us DIY folk to use the products seriously.
> 
> Best Regards,
> 
> Prot
> 
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> On Mon, 20 Jan 2003, Scott Evans, Gen Mgr wrote:
> 
>> Hello all,
>> 
>> After reading the interest in the ribbon controller ideas, I got to
>> thinking about touch controlled interfaces such as the Buchla 100 and
>> 200 interfaces as well as the Serge TKB. I had opportunity to use the
>> Buchla 100 controllers years ago, but I have never seen inside one of
>> these fun devices. Has anyone in the DIY community done any development
>> on these? Or perhaps some information on how the mechanics work? I
>> believe these are variable capacitance devices. I would love to build
>> something of this nature. Any guidance would be appreciated.
>> 
>> Scott