[sdiy-interim] MIDI guitar, the hard way

Mon Mar 26 20:11:46 CEST 2007

It will not work correctly.

The problem is that the two contacts
make a physical short.

(I'll try to explain without drawing...)

If you fret the Low E string at the first
fret... and the A String at the second fret...

The E string will detect at tht second fret.

The traditional fix is to cut the frets into
electrically isolated segnents.

The optical pickup could be DIY but it is likely
to respond poorly to amplitude. The string vibrates
in a precessing oval (like a spirograph if you remember those)...
not just up/down or side/side

H^) harry

>
>
>
>---- Original Message ----
>From: torpedo at demadrid.com
>To: harrybissell at copper.net
>Subject: RE: [sdiy-interim] MIDI guitar, the hard way
>Date: Mon, 26 Mar 2007 09:33:05 -0700
>
>>Hi Harry,
>>
>>I am not sure if I understand what you mention about the string/fret
>switches being monophonic.
>>
>>Sure there are two contacts per fretted string, but I could decide
>to only use the higher pitch switch.
>>
>>My idea is to scan through the strings with a microcontroller by
>putting a high level on a string and checking which frets are at high
>level. I will get a reading of two fret/string switches making
>contact and I will only use the one providing the higher pitch. Would
>that not work? I basically do not mind about each string being
>monophonic, that is how the guitar works anyway, but I would
>obviously not want the whole guitar-thing to be monophonic.
>>
>>One thing I was reading about which call my attention are optical
>pickups. How would that work in order to detect the strumming? How
>diyable is that idea (please remember I am only trying to capture the
>string strumming).
>>
>>Thanks all for your comments,
>>
>>Gorka
>>
>>--- harrybissell at copper.net wrote:
>>
>>From: harrybissell at copper.net
>>To: torpedo at demadrid.com, synth-diy at vermine.org
>>Subject: RE: [sdiy-interim] MIDI guitar, the hard way
>>Date: Mon, 26 Mar 2007 15:49:53 -0000
>>
>>Don't know if this is obvious but your
>>string / fret switch must be monophonic
>>(you can only fret one string at a time)
>>
>>The issue is that the strings make TWO
>>contacts, one toward the bridge, and another
>>toward the nut.
>>
>>Play any chord and you will see that most of them
>>would short a number of strings across a number
>>of frets... making an almost undecipherable mess.
>>
>>Roland has a patent using current transformers
>>build into the frets that might possibly work well
>>but would be hell for a DIY approach.  Might use
>>Hall effect these days, still tough....
>>
>>I'd look for a old G-Vox hex guitar pickup, used.
>>Cheapest way I can think of to get the amplitude
>>sensing...
>>
>>And if the system is really monophonic... why not use the
>>main pickups for amplitude ?
>>
>>Its a really tough problem, that is why it has not been commercially
>>successful (yet)
>>
>>H^) harry
>>
>>
>>
>>>
>>>
>>>
>>>---- Original Message ----
>>>From: torpedo at demadrid.com
>>>To: synth-diy at vermine.org
>>>Subject: RE: [sdiy-interim] MIDI guitar, the hard way
>>>Date: Mon, 26 Mar 2007 08:10:55 -0700
>>>
>>>>So... Now for a crazy idea that hopefully I will be able to work
>on
>>>whenever I finish the other 20 projects in the list:
>>>>
>>>>I have this korean made Les Paul style guitar which I want to
>become
>>>something useful. I thought about different artistic ways of using
>it
>>>and finally I realized it was born to be a MIDI guitar controler,
>but
>>>not the usual MIDI guitar with expensive Roland pitch to midi
>>>hardware. My thought was to connect every fret and every string to
>an
>>>AVR/PIC microprocessor, creating a matrix of switches between
>strings
>>>and frets. That by it self will make of my guitar a pretty cool
>synth
>>>controler (I know, no string bending... oh well) however, I will
>also
>>>like to be able to sense individual string strumming. I though
>about
>>>it and the only solution I found is using an Hex pickup (magnetic
>or
>>>piezo). Can you guys think of another solution for detecting
>>>individual string strumming? hopefully something DIY and cheap?
>Once
>>>the guitar/controler is finished, it does not necesary have to
>sound
>>>right when the strings are strummed.
>>>>
>>>>Would something like this work (from Dave_B in the diystompboxes
>>>forum):
>>>>http://davebales.com/me/stompboxStuff/hex_pickup.jpg
>>>>
>>>>Notes from Dave_B:
>>>>"Could it look something like this?  I left out the wires and
>guitar
>>>strings for clarity.  The white and gold part is the cut piezo, the
>>>black part underneath is foam rubber or something similar.  I've
>seen
>>>articles about glueing whole peizos to guitars for pickups (and
>tried
>>>with some success a long time ago).  If you put these close to the
>>>strings would it be enough to keep them from triggering notes from
>>>adjacent strings?"
>>>>
>>>>
>>>>Have in mind that I am not expecting to capture sound out of the
>>>piezos, only the amplitude of the strumming.
>>>>
>>>>Thanks,
>>>>
>>>>Gorka
>>>>
>>>>_____________________________________________________________
>>>>www.deMadrid.com , el correo gratuito de Madrid. 25 Mb de espacio.
>>>>
>>>>__________________________________________________________________
>__
>>>_
>>>>This is the interim list for synth-diy at dropmix.xs4all.nl.
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>>>y
>>
>>
>>
>>
>>
>>
>>_____________________________________________________________
>>www.deMadrid.com , el correo gratuito de Madrid. 25 Mb de espacio.

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