WIGGLING 'LITE' IN GUEST MODE

[revmutt]

Please bare with the non EE stuff but not asking is dumber.

I'm building a touch plate ala Buchla with very limited skills.
The plates are done, each has a trace to be soldered to something that will no double increase the output voltage to a point were it can trigger functions on a modular synth.

Basic details: 16 banana output which will need trimmers to tune each one, prefer battery power. I can't really read schematics and my math skills are horrible.

Not looking for great musicality nor expression, just and interface that will allow note control, modulate an oscillator, filter cut off.

I have read lots of articles and various lay outs that gave me some idea as to what i should be doing.

Have mercy and Help.

[sanders]

What do your plates look like? I've read that the size and shape of the plates has a lot to do with how it performs within a particular circuit.

A lot of people have reported to be working on DIY versions of a Buchla/Serge touch controller, for quite some time. I haven't found any results put up on the internet yet-- but I'm confident that someone will eventually do so. There's so much interest in this kind of project.

There are two touch-controller schematics that get mentioned, one from Paia, and one from Serge, published in Synapse magazine. But they're apparently both difficult to get working in practice.

There are a lot of simple schematics on the internet for capacitance on/off switches. If you could get one working, maybe the simplest version of a touch controller would be one that just momentarily switches a preset voltage on and off. As you say, you use trimmers or resistors to asign a different 'preset' voltage to each plate-- or use pots so that the voltages are variable (as on the Serge).

You'd also a gate detector (schmitt trigger, compartor, etc) to generate a timing pulse from this voltage.

[revmutt]

[sanders]

I don't know how an LFO would provide an on/off timing pulse for key presses-- but I'm not an EE either.

A comparator is a very simple circuit also, however. You can use it to compare two voltages and send a trigger/gate when a certain threshold is met. You can build it with an op-amp or a dedicated comparator IC-- and a few resistors. Dead simple.

You send your preset CV to the comparator, and you get a gate output.

Although, here is a circuit that will momentarily output a 5V pulse when you touch the plate. You could use it, vice versa, to trigger your preset CV:

http://www.discovercircuits.com/DJ-Circuits/5vtchremom2.htm

There are other circuits at this site, all designed designed for battery power. This might be a good place to start:

http://www.discovercircuits.com/DJ-Circuits/fingersw.htm

If you're using batteries to power this circuit, you needn't worry much about high voltage levels. However, you will have to learn to read schematics, regardless of whether you understand the circuit, in order to put this together. Just look for a symbol key to start reading them. There aren't that many symbols used in most schematics, so it's pretty easy.

Also, if you want my advise, initially concentrate on getting one key to work-- versus the whole keyboard. Perhaps that's obvious though.

Hope this helps a little. It's something I've been interested in also.

[revmutt]

Thanks that does help. I will try messing around with some comparators. I had originally planned to go with Scmitt Triggers since I actually have a bunch.

RE: LFO. I thought about having the trigger of each touch point trigger an LFO which would be send out instead of a gate.

One key at a time. Yeah, I did actually know that but if anyone else needs advice that one is very true.

[wetterberg]

a schmitt trigger IS a comparator

[revmutt]

[wetterberg]

but I mean, what are you looking for exactly? We can't guide you to schematics until you can read them, right? So how's about some basic DIY electronics reading? Or are you looking for something else?

[mono-poly]

[revmutt]

Thank you mono!

[revmutt]

Having found the perfect starting place in a Mimms schematic I should be fine. I can follow the basics of a schematic but it has not been a practiced science in my life like playing instruments.

I admit to having spent mot of my life outside the box and have left those who are great do their thing. At least I'm not ashamed of not knowing.