If you’ve ever plucked a metal ruler or banged it on the edge of a table, you know the vibrant, heady pulse of its taut rebound. The talented Moscow-based engineer Dmitry Morozov, who goes by ::vtol::, recognized the promise in that boinngggg and automated it. The result, a combination of processing power, two servo motors, and other items, is a programmable drum machine that makes all its sounds with a 20-centimeter metal ruler. This demo video shares some of its sonic and rhythmic potential.
The device is based on the school experience of imitating bass lines at the desk and a fun way to disturb teachers. The instrument can be classified as an automated plucked contrabass monochord. Changing the pitch is done by quickly changing how far the ruler is extended relative to the nut. Movements, plucks and presses of the ruler along the nut are driven by powerful and fast motors, which allows playing pretty fast lines. 2 pressing motors can work simultaneously or selectively, which allows you to choose the register: the range and amplitude of oscillations depends on the place in which the ruler is clamped before the pluck. The sound is picked up by a small piezo element, which is getting hits by a ruler directly (the instrument has no resonator). The instrument is equipped with 12 touch keys, each of which can be reassigned to a specific length of the ruler. A small OLED display is used to select modes, tune notes, and indicate processes and states.