The SJS-ONE is a digital software synthesizer with a dual analog filter designed as a shield for the Arduino Uno. Its name is derived from the venue where it was designed, the SyltJam 2011, which is an annual LAN-party like weekend event for synth-geeks in Malmö, Sweden. The description of the original DIY version can be found here.
An updated version of the SJS-ONE is available as a kit from Devsound. According to the developers, “SJS-ONE is a software defined 8-bit mono synthesizer with a dual (series) MAX261, switch-cap filter, which we are, as far as we know, the only ones to use at this point in a DIY-synthesizer. The filter can be programmed to work as low-pass, band-pass, high-pass, all-pass or a combination of filter modes.
The synth works as an Arduino shield, meaning that people can hack and modify the firmware at will. At the moment we have two firmwares finished, one paraphonic, supersaw synth, and one drummachine/sfx synth. More firmwares are in development!”
All files on this open source project can be found on Github.