He solved the problem by building the Tannin DIY MIDI controller ... to a PC via serial over USB. On the host PC side, he ran loopbe30 to create a virtual MIDI cable to Traktor, his DJ software.

[forrest] passed along this diy foot-pedal ‘midi’ controller ... the controller and using a laptop to generate signals via usb midi interface. Replace the keyboard pcb with a drum controller ...