The Synthfonio is a guitar-shaped MIDI instrument
Learning to play an an instrument well takes a lot of time, which many people don’t have. To address this, Franco Molina — who enjoys MIDI controllers and writing music, but describes himself as being terrible at playing the keyboard — created the Synthfonio.
Molina’s DIY device is vaguely reminiscent of a guitar, with a series of keys on the neck that indicate the chords and key signatures, and another set roughly positioned where you’d strum a guitar to play the notes.
The Synthfonio is assembled from laser-cut MDF sections, and utilizes a MKR WiFi 1010 to take care of I/O and MIDI functions. A second microcontroller in the form of an ATmega328 on a breadboard is used to produce actual synth sounds, though most Arduinos would be suitable either function.
The Synthfonio features 2 sets of keys, one to define chords and key signatures, and another one to actually play the notes. Whatever chord is pressed in the instruments neck keys, will define the pitch of the keys on the instrument handle. Similar to a guitar, violin, and other string instruments; with the added advance that the Synthfonio is a smart device that can deduce the chords being played from a single set of notes. This way, for example, the musician can use the handle keys to play chords, melodies, and arpeggios in the key of A, just by pressing the A key on the neck. In the same way, pressing the A key on the neck in conjunction with the C key (minor third of A) will activate an A minor tonality for the handle keys.
This can allow any player to execute a 4-chord melody, accompaniment, or even improvisation; with no more than one or two fingers in position.