MIDI Controller
When I was in the first year of my study, I learned to Program in Max MSP. It is really fun and there is a good free alternative called Pure Data.
At first I was just messing with a gamepad and Max MSP because I wanted to trigger samples and loops with my gamepad. Later the idea came up to hack the gamepad device by replacing the normal knobs and joysticks by push buttons. So its not really a "midi" controller because the software reads out the gamepad data and outputs that data as midi data.
So I made a midi controller in a cigar box to try out the push buttons. It worked!
But then I noticed a joystick is just two potmeters, one for the x-axis (horizontal movements) and one for the y-axis (vertical movements).
I decided to make a second one, but this time with potmeters and more knobs. By that time I found out I wasn't as original as I thought, it was done many times by a lot of people. But it was still a very interesting and educational project!
For musicians/audio programmers I would without a doubt recommend Max MSP/Pure Data
because they are educational and great tools to work with audio/midi.
If you want to write programs with midi in Max/PD these are objects you want to use:
midiin
midiout
ctlin
ctlout
notein
noteout
makenote
In this video I am demonstrating my "midi" controller. The music was put together in half a hour so not very interesting (for all I care) but as a demo it is quite nice.
I trigger a bunch of loops (in ableton) with the push buttons on the left side. The rotary buttons let me control some effects like filter frequency and the volume of loops. The toggle switches change the note numbers of al buttons so I can control others things when the toggle switches are switched. (I can make combinations with the toggle switches so I can use al 128 note numbers and a lot of controlnumbers for the rotary buttons)