DIY "ribbon controller" slide potentiometer-please help with blueprints!

[VvvvvV]

I want to modify my MIDI keyboard to replace some of the faders with lots of ribbon controllers. I'll post my progress here.

in the basic plan it's just a loop of ribbon wrapped around a sliding surface, with a couple of flexible wire contacts that change resistance as they get closer and further away from each other.

please help me to figure out all the best materials and layout configurations:

what is the best thing as a flexible strip of conductive material with a resistance of about 10K. over about over about 5-6cm?

What type of flexible glue can I use to fix the ribbons and the conductive materials? what's the most bendy and strong glue available?


http://asmidius.googlepages.com/home
someone has had a fiddle at something vaguely related, but it's not exactly a ribbon controller yet!

[Jarno]

Hi,

A colleague of mine is into electronic music, and he's building something with a ribbon controller kit. This company sells all sorts of stuff to build your own midi controller, I found the link:
http://www.doepfer.de/home_e.htm

Look for the R2M ribbon controller

Regards,

Jarno.

[VvvvvV]

loads of excellent gear there, I bumped into Doepfer on Google where there is tons of information on the ribbon controllers, and it seems that all ribbon controllers are reset to full resistance when the finger is taken away.

The design I have in mind is perhaps more referred to as a ribbon fader so that you can slide slide it and leave it to any lengths and it will stay in the same position even when the finger is taken away.

Here is a picture of the most simple possible design,it would only take about 15 minutes to glue everything together, it's just a ribbon of nylon with 50% conductive strip and 50% resistive strip wrapped around a plate, with a positive and a neutral signal at each end of the plate

In my case I wish to just find a passive solution that I can patch straight into a MIDI keyboard circuit board to replace an ordinary potentiometer

I would really love to know what kind of resistive material can be glued into a ribbon and that has about 10 K. resistance for approximately 6cm, that's the really hard bit!

[Jarno]

Hi,

Not to dampen your spirit, but building a ribbon controller from scratch in the way you sketched is really hard, I think.
The friction of the foil around the plate could mean that it is hard the move the foil. Not to mention the fact that the total resistance between the two poles is constant, regardless of the position of the ribbon. Or did I miss something?
If the problem with the doepfer controller is the one you mentioned, some kind of electrical or software solution seems easier to implement.

Best regards,

Jarno.

[VvvvvV]

I know what you mean it could be hard to make, but if you could get hold of all 5 or 6 parts it would be awesome. ideally there would be little rollers at either end to provide perfect scrolling, and the change in resistance would be because half of the ribbon is coated in conductive and the other one in resistant material, so the charge had always travelled down the least resistive length.

It's a bit of a hassle but it would be wonderful to make it one day. Here's another picture if you want.