Help me build Buchla/Serge style Capacitance Touch Keyboard?

Coriolis · Joined: Apr 11, 2005 Posts: 616 Location: Stilling, Denmark

Great initiative there, Ole... Cool

C

okvern · Posted: Fri Jul 25, 2008 1:51 pm Post subject:

Fellow Builders,

Speaking of the Buchla that I used to work with, here's an incredibly bad photo of our setup. When we had to close the studio down, I understand that the system was the subject of a small bidding war between the Smithsonian and the Stearns Musical Instrument Collection (at the University of Michigan).

Note the four model 112 touchplate keyboards! Also, just for Fonik--there's a model 292 quad lowpass gate in the upper left. It was from a later generation of modules, so it needed its own power supply--that's what's in the duct-taped box beneath it.

I've been missing this machine since 1994. Crying or Very sad

Thanks,

Ole

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Coriolis · Joined: Apr 11, 2005 Posts: 616 Location: Stilling, Denmark

Just beautiful!
Well, at least you have had the opportunity to play with a Buchla - I don't even think are any in my country... Crying or Very sad

C

mono-poly · Posted: Sat Jul 26, 2008 2:27 am Post subject:

European countrys with old Buchla are:

- Sweden
- Belgium
- Netherllands

As far as i know.

ericcoleridge · Joined: Jan 16, 2007 Posts: 889 Location: NYC

Check this out; Posted on matrixsynth: this guy is building synth modules with cut cardboard enclosures, and most interesting, control surfaces from "special conductive paint"!

This is the control surface I've been looking for; I'm imagining a plastic Shaeffer panel, with key sized etchings that could be filled in with this silver conductive paint. This would be so freakin cool!

http://noisedesign.blogspot.com/

http://www.youtube.com/watch?v=kYAyX5DWkdo

http://youtube.com/watch?v=9wU7DUODM5Q

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fonik · Posted: Mon Jul 28, 2008 9:28 am Post subject:

actually off topic, but:

what about using analog switch ICs (like the MAX323). the switch is on whenever logic in is at 0V. so couldn't i just selt the logic low by grounding it's input with my finger?
these switches could then control a diode matrix which has to be scanned...

such a keyboard would not provide any touch sensivity but it would be still nice for playing glissandos.

ericcoleridge · Joined: Jan 16, 2007 Posts: 889 Location: NYC

fonik · Posted: Mon Jul 28, 2008 11:54 am Post subject:

widdly · Posted: Mon Jul 28, 2008 6:58 pm Post subject:

If you don't need the pressure output, Mr Clack published a very simple touch switch here... http://electro-music.com/forum/topic-24011.html

I haven't tried it but it does look very simple.

CJ Miller · Joined: Jan 07, 2007 Posts: 368 Location: 127.0.0.1

I just got home from work a couple of hours ago, and am busy at building my 12-pad Synapse-style Serge keyboard. It is getting close to being done! Can't find those 430pF timing caps I bought a few weeks ago... Soon though, maybe I can have it all connected, cleaned, and dryed by the weekend so I can test it out. I am sure it'll be fun.

I do also want to check out the more complex Serge keyboard and the Buchlas in more detail later. Maybe once I finally make a few of my own PCBs. Even laying out a Buchla keyboard on (a very large piece of!) perfboard doesn't look to hard if one thinks strategy ahead of time. There are a lot of possibilities here to explore.

I'll get a little more done now before I've got to get to sleep

fonik · Posted: Wed Jul 30, 2008 6:52 am Post subject:

i am curious how important the shape of the keypads amy be? do you plan to test several shapes then?

CJ Miller · Joined: Jan 07, 2007 Posts: 368 Location: 127.0.0.1

ericcoleridge · Joined: Jan 16, 2007 Posts: 889 Location: NYC

Coriolis · Joined: Apr 11, 2005 Posts: 616 Location: Stilling, Denmark

CJ - it's very exciting that you are trying out the Synapse circuits, do keep us posted... Very Happy

C

dar303 · Joined: Jul 15, 2007 Posts: 97 Location: Sweden

Hi,

I would recommend the Serge TKB circuit for anyone that wants to build a complex touchcontroller with good feel and easy interfacing to sequencers or other logic circuits. Is should be available somewhere on the net, I found it over 10 years ago!
It is constructed of quite common CMOS chips with only one TTL chip (74150 if I remember correctly) that needs to be the exact type used in the schematic to get the touch sense to work.

The Buchla 221 is a beast, I actually have one in my pile of stuff to fix but it is a very big and scary project! Smile

I managed to repair another one about a year ago but it was hard. The schematic (wich I cannot share, sorry!) is hand drawn by Don across several pages. It has very complex logic due to the fact that is was meant to be a programming interface for the 300 system.
It has several fun features like generating a control voltage from a lamp and a photocell when the front panel flexes from you finger pressure, four preset voltages with pots activated when you touch the pads to the upper right.
The
PCB touch plates looks tin plated and are protected with a layer of laquer and are separated by thin strips of aluminium that sits in pockets in the pcb.

fonik · Posted: Sun Aug 03, 2008 11:53 pm Post subject:

Coriolis · Joined: Apr 11, 2005 Posts: 616 Location: Stilling, Denmark

dar303 · Joined: Jul 15, 2007 Posts: 97 Location: Sweden

There are no piezos in there, the scanning is built around a TTL multiplexer.

CJ Miller · Joined: Jan 07, 2007 Posts: 368 Location: 127.0.0.1

buchlajoe · Joined: Apr 19, 2008 Posts: 8 Location: new york

hi.
i have this and i dont use it with my system .... i would be happy to photograph any part of it for you to help out with your project.
this is the 216 keyboard made for the CBS performance system.

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mono-poly · Posted: Tue Aug 05, 2008 2:21 am Post subject:

I love to use it with my system Smile

CJ Miller · Joined: Jan 07, 2007 Posts: 368 Location: 127.0.0.1

buchlajoe · Joined: Apr 19, 2008 Posts: 8 Location: new york

here is a more detailed pic. let me know if you need something specific.

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scriptstyle · Joined: Jan 22, 2008 Posts: 250 Location: nj

I am currently in the middle breadboarding the touch responsive keyboard from the synapse article. What transistors did you guys use? im thinking i can just use 2n3904's?

andrewF · Posted: Fri Mar 06, 2009 8:27 am Post subject:

should be fine
I tried it with C1815 which is about as general purpose as it gets