https://www.noisio.de/ This is the ATtiny Punk Console (short ATPC). It's an easy to build synthesizer-kit based on the ATtiny85 microprocessor which is one of the smallest but also powerful members of the ATMEGA family (you probably already know by Arduino). The ATPC squeezes out the most of this little beetle. The synth is equipped with 4 potentiometers with body-contacts to tweak the sound. It's powered by center negative plug or 9V battery. You can trigger events by a push-button or via the programmable sync in- or out line. On the output side you'll find a variable lowpass filter and a volume controlled buffer stage to push out true 8bit sound. Because of the parallel 3.5mm and 6.3mm jack plugs you are able to link them in line as well as to interconnect and synchronize with other gear.