COMBINATION SENSOR
First Claim
1. A combination sensor, comprising:
- a pressure sensor having an actuator which has a first resonant frequency;
a cavity, coupled to the pressure sensor and able to receive a substance;
wherein the cavity, in an absence of the substance, has a second resonant frequency in response to excitation by the actuator;
wherein the cavity, in a presence of the substance, has a third resonant frequency in response to excitation by the actuator;
wherein the first resonant frequency differs from the second and third resonant frequencies; and
a sensor circuit which outputs a substance detected signal in response to the third resonant frequency in the cavity.
1 Assignment
0 Petitions
Accused Products
Abstract
One example discloses a combination sensor, comprising: a pressure sensor having an actuator which has a first resonant frequency; a cavity, coupled to the pressure sensor and able to receive a substance; wherein the cavity, in an absence of the substance, has a second resonant frequency in response to excitation by the actuator; wherein the cavity, in a presence of the substance, has a third resonant frequency in response to excitation by the actuator; wherein the first resonant frequency differs from the second and third resonant frequencies; and a sensor circuit which outputs a substance detected signal in response to the third resonant frequency in the cavity.
4 Citations
19 Claims
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1. A combination sensor, comprising:
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a pressure sensor having an actuator which has a first resonant frequency; a cavity, coupled to the pressure sensor and able to receive a substance; wherein the cavity, in an absence of the substance, has a second resonant frequency in response to excitation by the actuator; wherein the cavity, in a presence of the substance, has a third resonant frequency in response to excitation by the actuator; wherein the first resonant frequency differs from the second and third resonant frequencies; and a sensor circuit which outputs a substance detected signal in response to the third resonant frequency in the cavity. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
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15. A combination gas pressure sensor and carbon dioxide level sensor, comprising:
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a cavity, coupled to the pressure sensor and coupled to expose the cavity and the pressure sensor to a gas; wherein the gas pressure sensor includes a membrane; and wherein the cavity has a predetermined resonant frequency in response to excitation by the membrane when carbon dioxide is in the cavity.
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16. An article of manufacture comprising at least one non-transitory, tangible machine readable storage medium containing executable machine instructions for operating a combination sensor, the instructions comprising:
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exciting an actuator in a pressure sensor coupled to a cavity over a range of frequencies; monitoring a power level required to excite the actuator; comparing the actuator power level, at a predetermined frequency dependent upon the cavity dimensions, to a threshold power level; and outputting a substance detected signal if the monitored actuator power level at the predetermined frequency is below the threshold power level. - View Dependent Claims (17, 18, 19)
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Specification