Midipal controller expansion

I’m planning to add a breakout box to my midipal with pots and an expression pedal input, to make use of the “contrllr” app. Thing is, I’d like it to be easily detachable as I use the midipal on its own for simple midi plumbing when playing out live.
So I was thinking to run a short ribbon cable from the analog 1-8 pins to a connector, which could be accessed through the battery compartment. Has anyone out there done a similar mod? Any tips/pictures of your creations would be really helpful!

@elthorno

greetings from oz, how did you go with this…? I’m thinking ( well, in the process of really… ) putting together the same thing… ( more or less ) -using a VGA cable in this case to run out to a collection of controls: hopefully a couple of pots arranged as an x/y joystick, two linear touch strips and a couple of flex sensors. -all will be part of a large kinetic sculpture to add a degree of interactivity to a wall of various old tv screens… it’s for part of a galley installation

Hopefully I can use the midi-pal’s CNTRLR app to control aspects of a Kaoss-entrancer from afar. a little luck and this’ll work quite well.

It’d be great to see how your mod went, especially the wiring as I’m still a little hazy about exactly which points are the right ones…

you have:

[_] O O O O O O O ( O O )

Analouge 1…8, 0…3.3V GND 3.3V

( yeah ? )

-not sure about the wiring… I could guess ( though I’d only be about 75 % sure )

then there’s the other two 3.3V I/O’s on either side… ?

I just wrote a post about this for the main board… Though figured I should check your thread here first…
( there must be a few folks out there that set up CNTRLR with something… **_ right ? **_ )
~ : ]

will definitely post photos when it’s finished.

Hope your mod worked out well, ( having an expression pedal option in the CNTRLR app would be way cool )

L

I’ve thought about this; actually have a ribbon cable with connector coming out the bottom of the Midipal. The main things I noticed as limitations with what you could do are:
For things like the touch strips, there is no way to maintain the voltage once your finger is lifted off the sensor. So you can’t use touch to adjust a setting and keep it there.
The voltage will go from zero to 3.3V, with 1.65V in the middle. For something like a pitch bend wheel or a joystick, I think you would want + and - voltages with zero in the middle. Or maybe four separate positive voltages starting with zero in the middle. I couldn’t figure out a way to do these, but that’s not to say it’s not possible.
If you stay within the limitations, I think it will work well. I concluded that it was most suitable for potentiometer settings of parameters and touch sensors for temporary use (such as to alter a modulation source).
For a pot, I would wire the three tabs with 0V and 3.3V on the outer terminals, and one of the analog inputs on the central wiper. You can swap the 0V and 3.3V if you want to reverse the effect of the pot rotation.

Hi @wwwintercat. I ended up going down a different route using a cheap usb controller and an arduino in the end (see this thread) mainly because I realised that my midipal is almost always in use as a clock or channel filter. But it’s still on the ‘to do’ list!
To clarify on the expansion points: there is only one 3.3v connection, on the far right.
The image attached is for expanding a different controller (digital warrior), so ignore the bit with the switch. I think the wiring layout for the pots would work fine with the midipal.
Grenert makes some good points above regarding the touch strips. I was purely thinking about pots when I started. Good luck!