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.

Abstract: An electronic drum, comprising: a bottom member; a drum head; a drum sensor comprising: a passive resonant circuit mounted on the drum head and having a resonant frequency; and an active resonant circuit mounted on the bottom member and configured to excite the passive resonant circuit at the resonant frequency; a sensor driver to drive the active resonant circuit with an RF drive signal at the resonant frequency; and a detector to detect a level of RF signal from the driven active resonant circuit for sensing a position and/or velocity of the drum head; and a signal processor, coupled to the detector, configured to process the detected level of RF signal to sense a position and/or velocity of the drum head for determining when the drum head is hit.

Abstract: A sensing system for a computer input device. The sensing system comprises an actuator to attach to a key top or button. The actuator is moveable along an axis or hinged. The sensing system further comprises a biasing element to exert a biasing force on the actuator directed along the axis. The sensing system further comprises an actuator motion sensor associated with the actuator. The actuator motion sensor comprises a passive resonant circuit configured to be moved by the actuator and having a resonant frequency, an active resonant circuit configured to excite the passive resonant circuit at the resonant frequency, a sensor driver to drive the active resonant circuit with an RF drive signal at the resonant frequency, and a detector to detect a level of RF signal from a driven actuator motion sensor for sensing a position and/or velocity of the actuator.

Abstract: We describe a position sensor comprising drive electronics to drive a first tuned resonant circuit at a resonant frequency, a moveable mechanical control associated with a second, passive tuned resonant circuit and read-out electronics coupled to the first tuned resonant circuit to sense a position of the control. A first frequency of resonance of the first tuned resonant circuit matches a second frequency of resonance of the second, passive tuned circuit, and the first and second frequency resonance match a resonant frequency of the drive signal. The first tuned resonant circuit has an input coupled to the drive electronics, an output coupled to the read-out electronics and a resonant LC circuit coupled in series between the input and output. The variable output signal is dependent on an amplitude of a signal at the output of the first tuned resonant circuit.

Abstract: We describe a musical effect device comprising drive electronics to drive a first tuned resonant circuit at a resonant frequency, a moveable mechanical control associated with a second, passive tuned resonant circuit and read-out electronics coupled to the first tuned resonant circuit to sense a position of the control. A first frequency of resonance of the first tuned resonant circuit matches a second frequency of resonance of the second, passive tuned circuit, and the first and second frequency resonance match a resonant frequency of the drive signal. The first tuned resonant circuit has an input coupled to the drive electronics, an output coupled to the read-out electronics and a resonant LC circuit coupled in series between the input and output. The variable output signal is dependent on an amplitude of a signal at the output of the first tuned resonant circuit.

Abstract: We describe a musical effect device comprising drive electronics to drive a first tuned resonant circuit at a resonant frequency, a moveable mechanical control associated with a second, passive tuned resonant circuit and read-out electronics coupled to the first tuned resonant circuit to sense a position of the control. A first frequency of resonance of the first tuned resonant circuit matches a second frequency of resonance of the second, passive tuned circuit, and the first and second frequency resonance match a resonant frequency of the drive signal. The first tuned resonant circuit has an input coupled to the drive electronics, an output coupled to the read-out electronics and a resonant LC circuit coupled in series between the input and output. The variable output signal is dependent on an amplitude of a signal at the output of the first tuned resonant circuit.