As a standard tone control for the synthesizer, a blow controller is included in the DIY kit.
This blow controller is made with a piezo-element, this allows the user to vary the oscillator frequencies by playing the controller similar to playing a digeridoo.
We chose to do it this way for multiple reasons. First of all, a tone interfacing like this will make the user experience much more intuitive for people familiar with traditional music instruments. Secondary reason is that we want the users to fully benefit from the open-source DIY concept of the synthesizer. By introducing a blow controller instead of more traditional methods like rotary buttons or keyboards, we encourage the builder to use his creativity and hopefully inspire him to think outside the box.