This is an expansion of the multiplexer version of my Arduino Multi-Slider MIDI Controller from Part 2 to add a further 8 potentiometers.
- In a future project, I build a “shield” to make linking to the pots easier.
Warning! I strongly recommend using old or second hand equipment for your experiments. I am not responsible for any damage to expensive instruments!
These are the key Arduino tutorials for the main concepts used in this project:
If you are new to Arduino, see the Getting Started pages.
Parts list
- Arduino Uno or Nano
- Up to 8 10k linear (“slider” or “fader”) potentiometers
- 42×30 protoboard
- Male and female right-angle headers
- Connecting wires
This assumes you’ve already built the first circuit as described in Arduino Multi-Slider MIDI Controller.
The Circuit
There were several options I considered for adding more pots – even abandoning the idea of using all 16 inputs on one mux and building a complete second unit and letting the Arduino select which one to use. But in the end I opted for a second board linked to the first one via right-angled headers. This means they will slot together nicely one above the other and if I want them side by side, I can just use standard male to female jumper wires to do that.
The bottom half is the circuit as before, but I’ve re-routed the power line from the mux to the pots and then added a 10-way header to link to the second board.
The build of the second board starts of the same as the first one – mounting holes for the pots, then adding the pots and wiring up VCC and GND.
Then I added a female header (at a right angle) to link to the first board.
The first board, you may recall, had two jumpers added – one to “fix” the enable pin as active low, and one to force the fourth selection pin low. Well we now need to wire that the the Arduino to allow us to choose between all 16 inputs.
The Code
The code can pretty much be used exactly as is from part 2 although naturally it needs reconfiguring for 16 pots rather than 8.
#define NUMPOTS 16
int pots[NUMPOTS] = {0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15};
And then you need to decide what MIDI control messages to use!
Find the original code on GitHub here.
Closing Thoughts
This seems to work well now, but that is as far as I want to take it as a MIDI controller now. But I have some other ideas for what I’d like to do with 16 slider pots and an Arduino.
Kevin
Simple DIY Electronic Music Projects 