MIDI-guitar (was: Touch Switches/TS instruments )

[matti at devo.com]

Okay, this is even more off the topic, but casio's post brought something up: 
have you ever considered using a MIDI-guitar (not sure of the real name)? It's 
(those that I've seen, anyway) as follows: laser beams are emitted from the 
bridge, and picked up just before the neckboard; if one of the beams is blocked, 
an output is sent via MIDI, indicating that a note has been hit. Note control is 
done via four sets of keys replacing the frets on the neckboard. Now, assuming 
that you've equipped your modular with a MIDI->CV (or are using a modular 
emulator on your computer), this has a certain amount of potential.

ONly problem here, is that they are moderately expensive. Which brings me to a 
more relevant point -------> does anybody know of any schematics for such a 
device? I've looked myself, and not found any (the lasers may be a problem.....)


Quoting CasioRZ1 at aol.com:

> Hi all,
> 
> (beware, this is kinda long winded :-)
> 
> Allright, I missed the first part of this post, but regarding the PAiA
> touch 
> switches, they work really well.  In fact, I built a whole instrument
> out of 
> 'em.  
> 
> Basically, I wanted a way to be able to add a live element to my sets (I
> play 
> mostly jungle/drum n' bass and trance type stuff) but I suck at playing 
> keyboards.  However, I've been playing guitar a long time, so after
> countless 
> dissapointments with modern guitar synths (Axon, roland, et al), I just 
> decided to build my own.  
> 
> If you've tried guitar synths, you know that the problem w/tracking
> comes 
> from having the synth try to read and convert the pitch of the string,
> which 
> is gonna take a little time even in the best case scenario.  My solution
> is 
> to ditch the strings... hey, if I wanted guitar type sounds, I'd just
> play my 
> guitar!   
> 
> Sooo (inching slowly to the point) I found that PAiA touchswitch schem
> (thank 
> you PAiA!) and I found a keyboard schematic on TomG's site (again, thank
> you 
> TomG).  Initially, I was going to combine the two to be able to send CV
> by 
> hooking the touch switches up to relays that connected to the resistor
> bridge 
> thingy (sorry for my crappy terminology, I know very little about 
> electronics).  I hooked the whole thing up, and hey, it worked! 
> Pressing 
> different touch switches would make the resistance across the bridge
> change.  
>   
> 
> So, then I was going to build a Mad Mouse to control, but I encountered 
> <a href="http://www.geopath.com/~jraden/knobs.html">this guy's
> project</a>,
> which used a basic stamp to read pots and then send midi controller
> info.  
> Since my touchswitch instrument is basically just a gradiated pot
> anyway, I 
> decided I could probably do the same thing except send note info.
> 
> And... it works!  Really, really well, in fact.  It "tracks" better than
> any 
> guitar synth I've ever used, but it is limited.  First, it's monophonic 
> (which is what I wanted at the time, but I'm working on another one that
> is 
> six note poly). it's not velocity sensitive, and there's no string
> trigger so 
> you can't do pick style triplets (working on that too).  But, there is a
> cool 
> joystick on it that sends filter and cutoff controllers (since your
> right 
> hand isn't doing anything anyway :-)   
> 
> Here's a page w/a couple pics.  Yes, my wiring is awful, and it looks
> pretty 
> odd... but it works really well, and hey, it's my first electronics
> project!
> http://members.aol.com/casiorz1/mono.html
> <a href="http://members.aol.com/casiorz1/mono.html">yup, here it is</a>
> 
> BTW, in my experience, the touchswitches were *much* less reliable on a 
> solderless breadboard than when put upon a piece of protoboard.
> 
> BTW BTW, qprox.com sells touch switch ICs.  Much less wiring would be 
> invloved w/these than the PAiA circuit.  I've ordered some from 'em, but
> I've 
> yet to receive them.  I'll let the list know how they work out.
> 
> Thanks for reading!
> 
> Derek
> casiorz1 at aol.com
> 
> In a message dated 5/10/2000 3:29:43 PM Mountain Daylight Time, 
> sdcurtin at lucent.com writes:
> 
> << Subj:     RE: Possibly goofy idea...
>  Date:  5/10/2000 3:29:43 PM Mountain Daylight Time
>  From:  sdcurtin at lucent.com (Curtin, Steven D (Steven))
>  Sender:    owner-synth-diy at node12b53.a2000.nl
>  To:    chordman at flash.net, synth-diy at node12b53.a2000.nl,
> uzs159 at uni-bonn.de 
> ('René Schmitz'), honcho at paia.com ('honcho at paia.com')
>  
>  I tried the circuits on that page and couldn't get them to work, at
> least on
>  a protoboard.   Maybe I'm too much of a digital guy :).   This is why
> an
>  experimenter's kit with a working circuit board of these things, with
> the
>  pads right on the board, would be a great thing (hint, hint).
>  
>  Steve C
>  
>  -----------------------------------------------------------------
>  Steven Curtin  
>  Lucent Technologies Microelectronics
>  ph: (732)949-4404   fax: (732)949-6711
>  http://curtin.emf.org
>  sdcurtin at lucent.com
>  -----------------------------------------------------------------
>  
>  
>  > ----------
>  > From:    René Schmitz[SMTP:uzs159 at uni-bonn.de]
>  > Sent:    Wednesday, May 10, 2000 4:40 PM
>  > To:  chordman at flash.net; synth-diy at node12b53.a2000.nl
>  > Subject:     RE: Possibly goofy idea...
>  > 
>  > At 07:30 10.05.00, Scott Gravenhorst wrote:
>  > >Touch switches!  Didn't I read here that a CMOS gate input can
>  > >work as a touch switch?  If so, are there biasing requirements?
>  > >ESD protection things?  Output conditioning?  Could I make the 
>  > >pads by etching a board and coating it with clear lacquer?
>  > 
>  > Hi Scott!
>  > 
>  > The relevant link here is: http://www.paia.com/touchsw.htm
>  > I haven't tried it, if you do let us all know.
>  > 
>  > Bye,
>  >  René
>  > 
>  > 
>  > transconductance | uzs159 at uni-bonn.de
>  > isfutilepreparet | http://www.uni-bonn.de/~uzs159
>  > obeassimilated.. | http://members.xoom.com/Rene_Schmitz
>  > 
>  >>
>