Tuesday, July 01, 2008

Eight Pots to MIDI CC Data

I have been helping someone out to multiplex eight pots to MIDI CC data. This setup has been tested and found working.

Hardware Setup
The hardware setup is pretty straightforward
• One of the outer legs of the eight pots connect to ground
• The other outer leg connects to 5V
• The circuit uses a 4051 8 to 1 multiplex IC
• Pin 16 of the 4051 connects to 5V
• Pins 6, 7 and 8 of the 4051 connect to ground
• The middle leg of pot 1 connects to pin 13 of the 4051
• The middle leg of pot 2 connects to pin 15 of the 4051
• The middle leg of pot 3 connects to pin 14 of the 4051
• The middle leg of pot 4 connects to pin 12 of the 4051
• The middle leg of pot 5 connects to pin 1 of the 4051
• The middle leg of pot 6 connects to pin 5 of the 4051
• The middle leg of pot 7 connects to pin 2 of the 4051
• The middle leg of pot 8 connects to pin 4 of the 4051
• Pin 3 of the 4051 connects to Arduino analog in 0
• Arduino digital pins 2, 3 and 4 connect to pins 11, 10 and 9 of the 4051 respectively
• Arduino digital pin 1 connects to MIDI 5 pin din pin 5
• Ground connects to MIDI 5 pin din pin 2
• 5V connects to MIDI 5 pin din pin 4 via a 220 ohm resistor

Code
You can download the code here.

9 comments:

Joel said...

Really handy, thanks as always. I'll put this one away for when I try and make my very own "ultimate MIDI controller"! (I'm pretty sure that's something everyone tries at some point, right?)

g.p.macklin said...

Thank you, this is very helpful for a current project.

Sebastian Tomczak said...

Glad you gentlemen found it useful.

@ Joel - Yeah, surely everyone has tried it with some degree of success! Although I feel like I never get away from the drawing board because I can never decide on the exact specs for one that I would want to make and use... :)

Aaron Trubic said...

@sebastian - Thanks so much for this. I've tried a few configurations / sketches with the 4051 and this was the only one that really works. You've done us all a huge favor.

Aaron Trubic said...

Sebastian, I have a question. The 4051 sketch works fine but I cant seem to figure out how to send the digital pin data through the same open serial channel. I love the idea of squeezing out extra analog controls but I'd like to do the same thing with digital on the same controller...

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Harminder said...

First of all, fantastic project! Works perfectly, thank you very much for this.

Quick question for you though, I need to hookup 1 or 2 more 4501's with 8 pots on each and I've wired them as you described in "multiplexy" to analog inputs 0,1,2 but I'm a little baffled with the code, what do I need to edit to make them all work together?

Thanks again

Anonymous said...

Hey very cool stuff.
It is working perfectly, however i tried to go a step further using one more 4051 on the same digital inputs and can't figure out how to make it work. Can you please give me a hint?

joao_fonseca88@yahoo.com said...

Hi Sebastian, great project!

I'm trying to build my midi controller based on your's but, i get lots of noise from the pots, any idea why is this happening!? I'm just a newbie and i'm triying to figure out a way to minimize the noise. Hope you can help me.

JOE

Vibe Media Share said...

I now this alot to ask but could you create a patch for 12 potentiometers 4 faders and 50 digital inputs cause im tring to build a midi controler with tha arduino mega 2560 any help would be greatly appreciated