The Beetle Quantar was a guitar based MIDI controller made in the 1980s. The Quantar used ultasonic sensing technology to convert the fretted notes to a MIDI signal. A ultrasonic sound is transmitted across each string which is reflected back by the fingered fret. The timing of this reflected sound is then used to determine which fret is being played and converted into a MIDI code. Velocity information comes from the conventional electromagnetic pickups. The Quantar guitar controller came with an additional electronics box with select, hold, sustain and pedal controls. Yamaha used very similar technology on their G10 MIDI controller launched in 1988.