Keyboard sensor systems and methods
AssigneeSonuus Limited
InventorsJames Hastings Clark, John Michael McAuliffe
Life of this patent
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Abstract
A sensing system for a keyboard. Each key sensor comprises passive and active resonant circuits. The passive resonant circuit has a resonant frequency and the active resonant circuit excites the passive resonant circuit at the resonant frequency. A sensor driver drives the active resonant circuit with an RF drive signal, a multiplexing system multiplexes the drive signal such that simultaneously driven key sensors are separated by at least (k−1) keys, and a detector detects a level of RF signal from a driven key sensor for sensing a position and/or velocity of a key.
Claims16
A sensing system comprising a set of sensors for the keyboard of a keyboard instrument,
- wherein the keyboard has a plurality of keys;
- wherein each sensor comprises a passive resonant circuit for mounting on a moving part of a key and an active resonant circuit for mounting in a reference position, the passive resonant circuit having a resonant frequency, the active resonant circuit exciting the passive resonant circuit at the resonant frequency, each sensor further having a detector to detect a variation of a resonant signal in the active resonant circuit with a relative position of the active and passive resonant circuits to detect a position and/or velocity of the key;
- and
- wherein one or more coils of the active resonant circuit comprise two coils with opposing winding directions connected in series such that the one or more coils of at least the active resonant circuits have windings in opposite senses to thereby reduce interference between sensors of adjacent keys.
A method of sensing the position and/or velocity of a plurality of keys, in particular of a keyboard instrument, the method comprising:
- providing each key with a sensor comprising a passive resonant circuit for mounting on a moving part of a key and an active resonant circuit for mounting in a reference position, the passive resonant circuit having a resonant frequency, the active resonant circuit exciting the passive resonant circuit at the resonant frequency, each sensor further having a detector to detect a variation of a resonant signal in the active resonant circuit with a relative position of the active and passive resonant circuits to detect a position and/or velocity of the key;
- and
- reducing interference between sensors of adjacent keys by configuring one or more coils of the active resonant circuit to comprise two coils with opposing winding directions connected in series such that the one or more coils of at least the active resonant circuits have windings in opposite senses.
Dependencies are inferred from the claim text.