makey makey
Design your own controller with everyday materials like foil, velostat, playdough, graphite pencils, water or any other conductive material. Lots of info and examples on their own site: https://makeymakey.com
No need to install drivers , makey makey is plug and play.
Attach it through usb to your computer, close a circle of conduction bij connecting 'ground' and 'another trigger' & it shows up to be an external keyboard. Read the signal in an app like wordpad/texteditor to make sure you have the right connection.
In data flow software (like Isadora & touchdesigner) the makey is read through nodes like a 'keyboard In watcher' or 'KeyBoardIn'
Remember to always playtest your setup, as using a keyboard as input may also lead to unexpected/unwished results (like you interface being all over the place :)
Borrow Makey from the uitleen at IBB of PASTOE
or the Blackbox @ JK
see ipac for a makey on steroids