A couple of months ago, during Homework Festival I met a guy from Sofia who had a strange machine in his setup... he told me how cheap and funny it was, so I decided to order one on ebay. Last week I received my Gakken SX-150 and started searching around the net for hacks and mods, and I found several projects and articles describing possible ways of interfacing it with MIDI and various external sensors, but, since I was already doing some experiments with a DAC board, I decided to try it with my freshly received Gakken.
A few weeks ago I published the source code and the schematics of Synapse, an Arduino shield providing CV/gate I/O, and this is a real-world example of its usage, coupled with Arduino/Genuino 101, one of the most recent boards of the ever-growing Arduino family.