The making of the midi controller continues. After Novation Xio now the target is Nord Micro Modular. In the early era of planning it seemed as a giant project. First I thought I would build a midi keyboard, a midi controller and a complete eeepc(for nord editor) into a big house. I've used the eeepc for a week but the 10 inch screen(1024*600 resolution) proved to be not enough. There is no room for many modules.
So I gave up on the eeecp idea. I figured I don't even need the midi keyboard(there is one connected to daw). All I have left was the midi controller. So the whole thing stays small. There are 24 potmeters on a small front panel.( potmeters are in groups of six just like on the big Nord Modular)
The side panels:
Building of the casing:
The electronics remains the teensy board just like before, but this time with a native midi not USB.
The teensy/arduino midi library link is here:
This story started with me buying a Novation Xio 25 VA synth. After checking out the original presets I' ve strated to programming. Right there I faced with a problem. I'm sure there are people on Earth who can program a synth using sub-sub menu, but it'snot me. I 've found an editor for windows but not for osx. First I made an environment in Logic:
The Xio manual contains everything, some of the parameters receive CC message the others NRPN .
This way I could programm it quite well, but I still faced the problem the set the potmeters with the mouse, which I also don't like.
I played with a Teensy microcontroller board for a while now. (Teensy is an Arduino like usb developer board). It's able to handle usb midi, you only need to connect the potmeters to it and write a few lines of program code and you good to go. (USB class complient midi controller)
It worked with 2 potmeters. So I figured what if I would make a dedicated controller for the Xio.
Teensy has 12 analog A/D input, every input is connected with 8 channel multiplexer and I got a 12*8=96 potentiometer handling.
On the developer's website there is a schematic diagram and example program code what you need to "little bit" expand.
First of all I needed to figure out which 96 out of the 200 parameters is the most important to control the Xio. Logic environment was a big help in that.
After that I had the list and started to plan the frontpanel.
I've tried to make it small, putting the potmeters cca 25mm from each other. It resulted 5 rows and 19 columns (95 parameters). 91 potmeters and 4 switch.
Frontpanel, potmeters, knobs:
Since it strated as a experiment I didn't make a PCB, I built it on a breadboard.
It contains: a Teensy, 12 multiplexer IC (74HC4051), 3 connector (34pin).
The circuit is connected with floppy cables to the potmeters.
First test, 4 multiplexer, 1 cable. It worked fine.
Couple more solder and build a house and it's ready :))))
So now I have a dedicated USB midi controller for Xio. It can be use to control other device but parameters can not be set (it uses fixed CC and NRPN messages).