Environmental sensor circuit having a capacitive proximity sensor and magnetic field probe
AssigneeSemtech Corporation
InventorChaouki ROUAISSIA
Life of this patent
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Abstract
Environmental sensor circuit for a portable connected wireless device. The circuit includes a capacitive proximity sensor that determines when a user is close to the portable device. The device also has a magnetic field probe that provides a signal that indicates the position of a permanent magnet. The sensor circuit integrates both a digitizing unit and digital signal processing for the suppression of noise and drive in signals coming from the proximity sensor and from the magnetic field probe.
Claims16
An environmental sensor circuit for a portable connected wireless device, the circuit comprising a capacitive proximity sensor configured to determine whether a user is in proximity to the environmental sensor circuit by sensing variation in the capacitance of an electrode in electric connection with the electrical sensor circuit, a magnetic field sensor providing a signal proportional to a magnetic field strength, an analogue/digital converter configured to produce proximity digital values representative of the capacitance of the electrode and magnetic field digital values representative of the magnetic field strength, a thermometer, and a digital processor configured for suppressing unwanted noise and drift components from the proximity digital values and from the magnetic field digital values.
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A method of controlling a portable device through an user interface comprising:
- programming a host processor to present the user interface to a user and/or respond to interaction of an user with the user interface,
- digitizing with an analogue/digital converter a capacitance signal and a magnetic field signal,
- subtracting drift and noise components from digitized values of the capacitance and of the magnetic field in a digital signal processor, thereby producing useful digital values of the capacitance and of the magnetic field,
- making the useful digital values of the capacitance and of the magnetic field available to the host processor,
- altering the behaviour of the user interface based on the useful digital values of the capacitance and of the magnetic field.
Dependencies are inferred from the claim text.