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Turn an old “roller ball” mouse into a MIDI controller that can unlock new ways of making digital music.

Reimagining MIDI devices based on old electronics
I hate throwing away old electronics that still work but are no longer supported by modern appliances. My idea for this project came after finding an old PS/2 port roller ball computer mouse that I no longer had a use for. I’m a musician in my spare time and currently recording an EP with my metal band HELL SHEEP. I’m using MIDI controllers to create synth parts for our tracks on pro tools. Many people use a MIDI keyboard to write MIDI parts on the computer. I’m no pianist so I have been experimenting with different methods of writing MIDI, including using chess games and cellular automata. Trying to think of a way to re-use the old computer mouse, it occurred to me that it could be repurposed with Arduino as a nifty MIDI controller.

The Arduino MIDI computer mouse controller
I decided that the controller would make use of every feature on the old computer mouse I had. That meant mapping separate MIDI commands to left click, right click, mouse wheel click, mouse wheel scroll, and mouse movements on the X and Y axis.

I decided to map the midi pitch to the X axis position, and the midi volume (known as ‘velocity’) to the Y axis position. The position of the mouse wheel, would determine the value of a continuous controller. In the default settings this is CC1 - the mod wheel value.

The operation of the device is based around two modes which can be switched between by clicking the mouse wheel. In Glissando mode, the device can only play one MIDI note at a time. Left or right mouse clicks map to the same note. Moving the mouse while clicking down leads to a seamless movement between notes. In Interval mode, left and right mouse clicks map to different notes so it is possible to play intervals by first clicking one mouse button, then moving the X axis position of the mouse, and clicking the other mouse button.”

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