The idea of making cello-ish electronic instrument (other than using pickup to classic or reduced cello frame and sensing string vibrations) is certainly not new.

I've seen at least one implementation before, but honestly I was disappointed by little articulation possibilities of the bow. My idea was to use "physical" bow and sense its movement and pressure relative to the instrument, to allow more tone color, perhaps allowing to play more than one string at time (double stops) or even adding another sensors to allow "plucking" of the "strings" (pizzicato). Also, using strings on fingerboard - albeit not as oscillators itself, but merely as mean to determine what note wants the player.

The fingerboard part can be achieved by having four resistive wires above metallic fingerboard, having ground potential. When wire is pushed against metallic fingerboard, its length is decreased and its resistance drops. The wires will pass some current., this will result in change of voltage, that can feed the voltage controlled oscillator (VCO). Problem is that the oscillators will always work, unlike real cello, where oscillators (strings) resonate on players demand, dictated by bow movement.

As I wanted to have the bow "unplugged" from instrument body (just like for real instrument) I decided to make the bow from magnetic strip - this is steel strip, coated with ferrite magnet, which is then magnetized to have alternating magnetic domains, usually meant for precise length measurement. Then, I can employ four magnetic sensors in "pickup", each one belonging to one of oscillators. When bow is dragged across sensor, it produces impulses, whose frequency is proportional to bowing speed, usable as volume (amplitude) gate of the particular oscillator. What more, I can set up the sensors on force sensor, sensing pressure of bow - this can be input to color (frequency filter) of the oscillator.

To sense taps by fingers (pizzicato) I can employ touch sensors. I opted for piezoelectric ones, as those seemed to be most suited to sense dynamic pressure changes.

Well, it looks simply enough, huh? Stay tuned for new project logs.