| Author |
Message |
a.b.o.z.
Joined: Feb 07, 2007
Posts: 351
Location: Zagreb, Croatia
Audio files: 7
G2 patch files: 4
|
 Posted: Fri Aug 31, 2007 10:09 am Post subject:
capacitance touch switch |
  |
|
I'm wondering of a CV controller keyboard that uses touch switches instead of keys. Something like Buchla's touch plate keyboard.
came across this http://www.discovercircuits.com/C/capacitance-sw.htm today and wondering did anyone tried to do something like this.
anyone?
cheers
Ivan |
|
|
Back to top
|
|
 |
bugbrand
Joined: Nov 27, 2005
Posts: 846
Location: Bristol, UK
Audio files: 1
G2 patch files: 1
|
|
|
Back to top
|
|
|
a.b.o.z.
Joined: Feb 07, 2007
Posts: 351
Location: Zagreb, Croatia
Audio files: 7
G2 patch files: 4
|
| Posted: Sun Sep 02, 2007 5:42 am Post subject:
|
|
|
thnx bugbrand.
I was thinking of a simple touch switches to be hooked on e.g mfos single buss 1V/octave keyboard controller. you know what i mean? every key is one switch.
On those touch switch keyboards (paia and serge) every key has it's output. |
|
|
Back to top
|
|
|
a.b.o.z.
Joined: Feb 07, 2007
Posts: 351
Location: Zagreb, Croatia
Audio files: 7
G2 patch files: 4
|
|
|
Back to top
|
|
|
Clack
Joined: Aug 08, 2005
Posts: 438
Location: Walthamstow - london
Audio files: 5
G2 patch files: 1
|
| Posted: Sun Sep 02, 2007 7:43 am Post subject:
|
|
|
you could try it with a 4016? would be more economical, not sure how it would respond. possibly you need caps to smooth it out?
_________________
Clacktronics.co.uk |
|
|
Back to top
|
|
|
a.b.o.z.
Joined: Feb 07, 2007
Posts: 351
Location: Zagreb, Croatia
Audio files: 7
G2 patch files: 4
|
| Posted: Sun Sep 02, 2007 7:48 am Post subject:
|
|
|
| yes I have them in mind too. i'll have to try it. |
|
|
Back to top
|
|
|
bugbrand
Joined: Nov 27, 2005
Posts: 846
Location: Bristol, UK
Audio files: 1
G2 patch files: 1
|
|
|
Back to top
|
|
|
ian-s
Joined: Apr 01, 2004
Posts: 2672
Location: Auckland, New Zealand
Audio files: 42
G2 patch files: 626
|
| Posted: Sun Sep 02, 2007 12:14 pm Post subject:
|
|
|
| a.b.o.z. wrote: | silly me 
i found a way. very simple. one transistor bc337 and relay. |
That looks like a resistive touch switch.
Unlike the capacitive type, you need a two part touch pad.
They can have problems with finger oils making them stick in the 'on' state. |
|
|
Back to top
|
|
|
a.b.o.z.
Joined: Feb 07, 2007
Posts: 351
Location: Zagreb, Croatia
Audio files: 7
G2 patch files: 4
|
| Posted: Sun Sep 02, 2007 12:26 pm Post subject:
|
|
|
| g2ian wrote: | | a.b.o.z. wrote: | silly me
i found a way. very simple. one transistor bc337 and relay. |
That looks like a resistive touch switch.
Unlike the capacitive type, you need a two part touch pad.
They can have problems with finger oils making them stick in the 'on' state. |
yeah I noticed the difference but they're way more simple...
bugbrand thanx for that one too.
it's protoboardin time  |
|
|
Back to top
|
|
|
a.b.o.z.
Joined: Feb 07, 2007
Posts: 351
Location: Zagreb, Croatia
Audio files: 7
G2 patch files: 4
|
| Posted: Sun Sep 02, 2007 2:28 pm Post subject:
|
|
|
one more. I found this one. It's pretty simple. One question to someone who knows.
This output...it will put some transistor to close? Or even 4016? Is this correct?
 |
|
|
Back to top
|
|
|
a.b.o.z.
Joined: Feb 07, 2007
Posts: 351
Location: Zagreb, Croatia
Audio files: 7
G2 patch files: 4
|
| Posted: Mon Sep 03, 2007 9:56 am Post subject:
|
|
|
the answer is yes. with this output you can drive other transistor (witch acts as a switch). all you need to do is make one of these for all keys on keyboard.
i'm thinking of a layout sometime in future.
cheers |
|
|
Back to top
|
|
|
Narbotic
Joined: Jun 24, 2007
Posts: 51
Location: Brooklyn, US
|
| Posted: Tue Sep 04, 2007 11:49 pm Post subject:
|
|
|
Strange, I had read the PAiA article yesterday then been thinking about using it to drive the MFOS board while I was on the train - now I find this thread!
a.b.o.z. - Keep us posted of your progress
_________________
- Collin Mel |
|
|
Back to top
|
|
|
v-un-v
Janitor
Joined: May 16, 2005
Posts: 8932
Location: Birmingham, England, UK
Audio files: 11
G2 patch files: 1
|
| Posted: Wed Sep 05, 2007 2:47 am Post subject:
|
|
|
The original Wasp keyboard was capacitance based. To be honest- it drove me to distraction as I found that it didn't always trigger, or it would just trigger anyway(when you didn't want it to)- which was equally infuriating. I think this design was based on the 4016 chip.
_________________
ACHTUNG!
ALLES TURISTEN UND NONTEKNISCHEN LOOKENPEEPERS!
DAS KOMPUTERMASCHINE IST NICHT FÜR DER GEFINGERPOKEN UND MITTENGRABEN! ODERWISE IST EASY TO SCHNAPPEN DER SPRINGENWERK, BLOWENFUSEN UND POPPENCORKEN MIT SPITZENSPARKSEN.
IST NICHT FÜR GEWERKEN BEI DUMMKOPFEN. DER RUBBERNECKEN SIGHTSEEREN KEEPEN DAS COTTONPICKEN HÄNDER IN DAS POCKETS MUSS.
ZO RELAXEN UND WATSCHEN DER BLINKENLICHTEN. |
|
|
Back to top
|
|
|
blue hell
Site Admin
Joined: Apr 03, 2004
Posts: 24423
Location: The Netherlands, Enschede
Audio files: 297
G2 patch files: 320
|
| Posted: Wed Sep 05, 2007 4:08 am Post subject:
|
|
|
| v-un-v wrote: | | To be honest- it drove me to distraction |
It's not so easy to make reliable touch contacts indeed
_________________
Jan
also .. could someone please turn down the thermostat a bit.
 |
|
|
Back to top
|
|
|
richardc64
Joined: Jun 01, 2006
Posts: 679
Location: NYC
Audio files: 26
|
| Posted: Wed Sep 05, 2007 5:13 am Post subject:
|
|
|
Some bad ideas refuse to die. Wasn't it determined in the 1980s, with the Atari 400 and Timex-Sinclair, that non-moving keys suck?
Now that I got that off my chest...
| a.b.o.z. wrote: | | ...all you need to do is make one of these for all keys on keyboard. |
Geeze, that'll be alot of parts, even for a relatively short keyboard. Here's something I breadboarded awhile ago. (OK, a looong while ago.) The R C values are lost to antiquity.
The idea here is to delay the clock signal with the sensitivity pot and capacitor so that the rising edge arrives at the 'C374 latch Clk input while the inverted, non-delayed clock on the D inputs is low. Touching point 'T', (which can be insulated, not necessarily a bare contact,) delays the inverted clock so that it's still high on the corresponding D when the latch gets Clk'ed.
There's no proportional levels in this, just 0s and 1s at the 'C374 Q outputs. Sorry my original drawing doesn't have parts values. It's something to tinker with. It might be necessary to add a small cap 10-47pF to Gnd at each 'T'. The clock frequency will also have an affect on the sensitivity.
| Description: |
|
| Filesize: |
8.65 KB |
| Viewed: |
11860 Time(s) |
|
_________________
Revenge is a dish best served with a fork... to the eye |
|
|
Back to top
|
|
|
frijitz
Joined: May 04, 2007
Posts: 1734
Location: NM USA
Audio files: 54
|
| Posted: Wed Sep 05, 2007 9:52 am Post subject:
|
|
|
| richardc64 wrote: | | Some bad ideas refuse to die. Wasn't it determined in the 1980s, with the Atari 400 and Timex-Sinclair, that non-moving keys suck? |
Perhaps. They work OK for my woodwind-type controller, though, so I would say it depends on the application and on the user.
| Quote: |
Geeze, that'll be alot of parts, even for a relatively short keyboard. Here's something I breadboarded awhile ago. (OK, a looong while ago.) The R C values are lost to antiquity.
The idea here is to delay the clock signal with the sensitivity pot and capacitor so that the rising edge arrives at the 'C374 latch Clk input while the inverted, non-delayed clock on the D inputs is low. Touching point 'T', (which can be insulated, not necessarily a bare contact,) delays the inverted clock so that it's still high on the corresponding D when the latch gets Clk'ed. |
Yep, straight out of the CMOS Cookbook.
Here's how I did mine:
http://home.comcast.net/~ijfritz/st_cir5.htm
Ian |
|
|
Back to top
|
|
|
slabman
Joined: Sep 01, 2005
Posts: 102
Location: UK
|
| Posted: Mon Sep 10, 2007 2:44 pm Post subject:
dedicated chips |
|
|
| Try www.qprox.com - they have some dedicated chips that 'should' make it simple to build a touch keyboard. Not too pricey either |
|
|
Back to top
|
|
|
slabman
Joined: Sep 01, 2005
Posts: 102
Location: UK
|
|
|
Back to top
|
|
|
|
Forum index » DIY Hardware and Software
FAQ
Calendar
Search
Memberlist
Usergroups
Register
Profile
Log in to check your private messages
Log in
Chat Room
