Piezo key sensing circuit and method for testing the piezo key sensing circuit
AssigneeDiehl AKO Stiftung & Co. KG
InventorTony Dmytriw
Life of this patent
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Abstract
A method tests a piezo key sensing circuit having a piezo element and verifies that it is properly functioning. A capacitance of the piezo element is discharged. Then the capacitance of the piezo element is charged during a predetermined time period. An output signal of the piezo element is measured during the predetermined time period resulting in a measured output signal. An operating condition of the piezo key sensing circuit is determined based on the measured output signal.
Claims20
A method for testing a functionality of a piezo key sensing circuit, which comprises the steps of:
- discharging a capacitance via a first terminal of a piezo element;
- charging the capacitance via the first terminal of the piezo element during a predetermined time period, the charging of the capacitance of the piezo element being initiated by applying a high impedance state to the first terminal of the piezo element;
- measuring an output signal of the piezo element during the predetermined time period resulting in a measured output signal;
- and
- determining an operating condition of the piezo key sensing circuit based on the measured output signal.
A method for testing a piezo key sensing circuit, which comprises the steps of:
- charging a capacitance of a piezo element via a first terminal;
- discharging the capacitance of the piezo element at the first terminal during a predetermined time period, the discharging of the capacitance of the piezo element being initiated by applying a high impedance state to the first terminal of the piezo element;
- measuring an output signal of the piezo element during the predetermined time period resulting in a measured output signal;
- and
- determining an operating condition of the piezo key sensing circuit based on the measured output signal.
A piezo key sensing circuit, comprising:
- a microcontroller having a digital I/O pin and an analog-to-digital converter (ADC) pin;
- an amplifier circuit having an output coupled to said ADC pin;
- a piezo element connected directly to said digital I/O pin and to said amplifier circuit;
- said microcontroller programmed to:
- discharge a capacitance of said piezo element via said digital I/O pin;
- charge the capacitance of said piezo element during a predetermined time period via said digital I/O pin, a charging of the capacitance of said piezo element being initiated by applying a high impedance state to said digital I/O pin;
- measure an output signal of said piezo element during the predetermined time period resulting in a measured output signal via said ADC pin;
- and
- determine an operating condition of the piezo key sensing circuit based on the measured output signal.
A piezo key sensing circuit, comprising:
- a microcontroller having a digital I/O pin and an analog-to-digital converting (ADC) pin;
- an amplifier circuit having an output coupled to said ADC pin;
- a piezo element connected directly to said digital I/O pin and to said amplifier circuit;
- said microcontroller programmed to:
- charge a capacitance of said piezo element;
- discharge the capacitance of said piezo element during a predetermined time period, a discharging of the capacitance of said piezo element being initiated by applying a high impedance state to said digital I/O pin;
- measure an output signal of said piezo element during the predetermined time period resulting in a measured output signal;
- and
- determine an operating condition of the piezo key sensing circuit based on the measured output signal.
Dependencies are inferred from the claim text.