Capacitive switch reference method
First Claim
1. An apparatus, the apparatus being a capacitive switch operated by sensing the presence of a finger:
- said apparatus comprising;
a capacitive switch sensor, providing a capacitive switch signal indicating the presence of the finger;
a capacitive reference sensor, sensing a capacitive reference signal; and
an electronic circuit, receiving the capacitive switch signal and the capacitive reference signal,the electronic circuit detecting switch activation by comparing the capacitive switch signal to a threshold signal level,the threshold signal level being adjusted as a function of the capacitive reference signal,the capacitive reference sensor sensing the capacitive reference signal only when the finger is in proximity to the capacitive reference sensor.
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Accused Products
Abstract
An example capacitive switch apparatus comprises a capacitive switch sensor providing a capacitive switch signal, a capacitive reference sensor providing a capacitive reference signal, and an electronic circuit, receiving the switch and reference signals and detecting switch activation by comparing the switch signal level with a threshold level. The threshold level is adjusted as a function of the reference signal level. The reference signal is obtained, for example during periods of operator proximity to the reference sensor. For a finger-operated switch, the reference signal is obtained when a finger is proximate the reference sensor.
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Citations
17 Claims
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1. An apparatus, the apparatus being a capacitive switch operated by sensing the presence of a finger:
- said apparatus comprising;
a capacitive switch sensor, providing a capacitive switch signal indicating the presence of the finger; a capacitive reference sensor, sensing a capacitive reference signal; and an electronic circuit, receiving the capacitive switch signal and the capacitive reference signal, the electronic circuit detecting switch activation by comparing the capacitive switch signal to a threshold signal level, the threshold signal level being adjusted as a function of the capacitive reference signal, the capacitive reference sensor sensing the capacitive reference signal only when the finger is in proximity to the capacitive reference sensor. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
- said apparatus comprising;
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11. A capacitive switch apparatus for a vehicle operated by sensing the presence of a vehicle operator hand;
- said apparatus comprising;
a capacitive switch sensor, operable to provide a capacitive switch signal indicating the presence of the vehicle operator hand; a capacitive reference sensor, operable to sense a capacitive reference signal; and an electronic circuit, receiving the capacitive switch signal and the capacitive reference signal, the electronic circuit detecting switch activation by comparing the capacitive switch signal with a threshold signal level, the threshold signal level being adjusted as a function of a signal level of the capacitive reference signal, the capacitive reference signal being sensed only during periods when the vehicle operator hand is in proximity to the capacitive reference sensor. - View Dependent Claims (12, 13, 14, 15)
- said apparatus comprising;
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16. A method of detecting an activation of a capacitive switch within a vehicle by sensing the presence of a hand of a vehicle operator, the method comprising:
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sensing a reference signal from a capacitive reference sensor only when the hand of the vehicle operator is proximate the capacitive reference sensor; using the reference signal to adjust a threshold level for switch activation to determine an adjusted threshold level; obtaining a capacitive switch signal from a capacitive switch sensor; comparing the capacitive switch signal with the adjusted threshold level to detect activation of the capacitive switch. - View Dependent Claims (17)
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Specification