[sdiy] Force Sensing Resistor

JH. jhaible at debitel.net
Sat Sep 15 09:31:55 CEST 2007

I came late into this thread. Edward, have you built your own keboard with 
polyphonic aftertouch ?!
What keyboard action did you use to retrofit with QTC pills?
Do you have any pictures of what you've built?

I thought the Pills respond in en exponential rathe than linear way. Thought 
I read this somewhere.
I've ordered some of these from Maplin yesterday. Curious to try them 


----- Original Message ----- 
From: "Edward King" <edwardcking2001 at yahoo.co.uk>
To: <xyzzy at sysabend.org>
Cc: "Synth DIY List" <synth-diy at dropmix.xs4all.nl>
Sent: Saturday, September 15, 2007 5:42 AM
Subject: Re: [sdiy] Force Sensing Resistor

Hi Tom!

Actually, although they make some products in the uk, they also have a
manufacturing unit in the far east (or at least in that direction).

I went a bit overboard with them when I came acrross them and have given
proportional control to various objects that really shouldnt have
Let me know if you want me to send you over a couple of samples as I've got
to order some more in anyway.

A nice quickie experiment (proof of concept) is find someone with a slightly
earlier model car, pop off the electric window switch, shove a QTC pill in
between the contacts and hey presto! You have (or should have depending on
the car and switching arrangement) proportional electric window control :o)

for more relevant uses, the forum on peratechs website will be helpful in
getting the best out of the materials and if you want more hints and
practical advice, just gimme a shout. Remember, the output is _very_nearly_
linear but not quite so for finer control, you need to tweak things a bit.


----- Original Message ----- 
From: "Tom Arnold" <xyzzy at sysabend.org>
To: "Edward King" <edwardcking2001 at yahoo.co.uk>
Sent: Friday, September 14, 2007 5:32 AM
Subject: Re: [sdiy] Force Sensing Resistor

> On Fri, Sep 14, 2007 at 05:26:45AM +0300, Edward King wrote:
>> QTC cable is what Im using for keyboards that only need aftertouch for
>> the
>> whole board. For individual aftertouch (I can never remember whether its
>> called poly or mono) QTC pills.
> Oh.  Nifty, How did I miss this product??   Looks like its made in the UK?
>> Both QTC cable and QTC pills are very cheap and pretty linear.
> For Poly I'm back to playing with Hall Effect sensors since they have
> dropped in price.  I hope to have something to report soon...
> -- 
> --------------------------------------------------------------------
> - Tom Arnold           -  "...is it a virus, a drug, or a religion?"
> - Sysabend Caretaker   -    Juanita Shrugs. "What's the difference?"
> ------------------------       -- Neal Stephenson,  Snow Crash

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