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.
Claims15
A sensing system for a keyboard, the sensing system comprising:
- a plurality of key sensors, wherein each of the plurality of key sensors comprises:
- a passive resonant circuit, and an active resonant circuit, the passive resonant circuit having a resonant frequency, the active resonant circuit being configured to excite the passive resonant circuit at the resonant frequency;
- the sensing system further comprising:
- at least one sensor driver to drive the active resonant circuits with an RF drive signal;
- a multiplexing system to multiplex the RF drive signal such that simultaneously driven key sensors are separated by at least (k−1) keys, where (k−1) is an integer equal to or greater than 1;
- and
- at least one detector to detect a level of an RF signal from a driven key sensor for sensing a position and/or velocity of a key associated with the key sensor.
A method of compensating a response of a keyboard, the keyboard comprising keys each having a sensor comprising an active resonant circuit, a passive tuned resonant circuit and a detector, the method comprising:
- retrieving from storage a detected initial output signal of the sensor, Ot0, at a first time, t0, wherein at t0 said active resonant circuit is being driven at a frequency below a resonant frequency of said active resonant circuit;
- and periodically, for at least one of the sensors:
- detecting a later output signal of the sensor, Ot1, at a time after t0;
- calculating an adjustment value, wherein the adjustment value is a difference between the initial output signal of the sensor and the later output signal of the sensor;
- and
- compensating the response of the keyboard by adjusting an operational output of the sensor using the adjustment value, where the operational output is an output from the sensor when the active resonant circuit is being driven at the resonant frequency of the active resonant circuit.
A sensing system for a keyboard, the sensing system comprising:
- a plurality of key sensors, wherein each of the plurality of key sensors comprises:
- a passive resonant circuit, and an active resonant circuit, the passive resonant circuit having a resonant frequency, the active resonant circuit being configured to excite the passive resonant circuit at the resonant frequency;
- the sensing system further comprising:
- at least one sensor driver to drive the active resonant circuits with an RF drive signal;
- and
- at least one detector to detect a level of an RF signal from a driven key sensor for sensing a position and/or velocity of a key associated with the key sensor,
- wherein positions of physically adjacent passive resonant circuits of adjacent key sensors from among the plurality of key sensors are offset.
Dependencies are inferred from the claim text.