Touch and proximity sensor control systems and methods with improved signal and noise differentiation
First Claim
1. A method of differentiating between an intended activation of a touch sensor and noise in a circuit, said method comprising the steps of:
- receiving a touch sensor reading;
calculating an amount of deviation between said touch sensor reading and an average sensor reading;
adding said amount of deviation to a cumulative deviation tally;
obtaining a ratio of said cumulative deviation tally to a scale;
incrementing a counter that tracks the number of touch sensor readings included in said cumulative deviation tally; and
sending an output signal indicative of a touch if said ratio meets or exceeds a threshold and said counter falls within a predetermined range.
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Accused Products
Abstract
The present invention discloses a novel new technique for detecting an intended activation of a touch sensor in the presence of noise. An algorithm is described that compares a cumulative deviation of a touch sensor reading to a scale to obtain a ratio expressed as a percentage. The percentage is compared against a target threshold and the period required to reach the threshold is examined to determine whether the rise or fall in touch sensor readings is attributable to a touch or to system noise. Additional disclosed embodiments describe circuits configured to operate in a noisy environment and have touch sensors arranged as arrays that are capable of detecting a direction and speed of a human-like contact.
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Citations
36 Claims
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1. A method of differentiating between an intended activation of a touch sensor and noise in a circuit, said method comprising the steps of:
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receiving a touch sensor reading; calculating an amount of deviation between said touch sensor reading and an average sensor reading; adding said amount of deviation to a cumulative deviation tally; obtaining a ratio of said cumulative deviation tally to a scale; incrementing a counter that tracks the number of touch sensor readings included in said cumulative deviation tally; and sending an output signal indicative of a touch if said ratio meets or exceeds a threshold and said counter falls within a predetermined range. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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14. A method of differentiating between an intended activation of a touch sensor and noise in a circuit, said method comprising the steps of:
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receiving a touch sensor reading; calculating an amount of deviation between said touch sensor reading and an average sensor reading; adding said amount of deviation to a cumulative deviation tally; obtaining a ratio of said cumulative deviation tally to a scale; comparing said ratio against a stored ratio to determine whether said ratio is increasing; performing the following steps if said ratio is increasing; 1. incrementing a counter that tracks the number of touch sensor readings included in said cumulative deviation tally; and 2. sending an output signal indicative of a pressed touch sensor if said ratio meets or exceeds a threshold and said counter falls within a predetermined range; and performing the following steps if said ratio is not increasing; 1. incrementing a counter that tracks the number of touch sensor readings included in said cumulative deviation tally; and 2. sending an output signal indicative of a released touch sensor if said ratio meets or exceeds a threshold and said counter falls within a predetermined range. - View Dependent Claims (15, 16, 17, 18, 19, 20, 21, 22, 23)
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24. A method of analyzing readings from a touch sensor to differentiate between noise and a presence of a human-intended activation of said touch sensor, said method comprising the steps of:
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receiving a first group of sensor readings; calculating an average reading of said first group; receiving a second group of sensor readings; calculating a deviation from said average reading of the first group for each sensor reading in said second group; calculating a cumulative deviation for said second group; obtaining a ratio of said cumulative deviation to a maximum value; and indicating that said human-intended activation has occurred if; said ratio meets or exceeds a threshold value; and said threshold is met or exceeded within a predetermined number of sensor readings. - View Dependent Claims (25, 26, 27, 28, 29)
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30. A method of differentiating between an intended activation of a touch sensor and noise in a circuit, said method comprising the steps of:
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receiving a signal that includes a plurality of touch sensor readings that are multiplexed into said signal; demultiplexing said signal to isolate a single touch sensor reading; calculating an amount of deviation between said single touch sensor reading and an average sensor reading; adding said amount of deviation to a cumulative deviation tally; obtaining a ratio of said cumulative deviation tally to a scale; incrementing a counter that tracks the number of touch sensor readings included in said cumulative deviation tally; and sending an output signal indicative of a touch if said ratio meets or exceeds a threshold and said counter falls within a predetermined range. - View Dependent Claims (31, 32)
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33. A capacitive responsive circuit for detecting a proximity or touch of a person in a noisy environment and for controlling power to a load, said circuit comprising:
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an oscillator that provides a periodic output signal; a touch circuit coupled to said oscillator to receive said periodic output signal, said touch circuit including a touch sensor for receiving tactile command information from an operator, said touch circuit further comprising a low pass filter for converting a frequency of said periodic output signal to a DC voltage value; and a detector circuit coupled to said touch circuit, said detector circuit including a microcontroller that receives a plurality of said DC voltage values over time and generates an output signal in response to an intended activation of said touch sensor, said microcontroller configured to monitor said plurality of DC voltage values and to detect an intended activation of said touch sensor based at least in part on a comparison of a ratio of a cumulative deviation of said plurality of DC voltage values from an average voltage value to a scale against a threshold ratio.
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34. A capacitive responsive circuit for detecting a proximity or touch of a person in a noisy environment and for controlling power to a load, said circuit comprising:
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an oscillator that provides a periodic output signal; a touch circuit coupled to said oscillator to receive said periodic output signal, said touch circuit including a plurality of touch sensors that receive tactile command information from an operator, said touch circuit further comprising a low pass filter associated with each of said plurality of touch sensors for converting a frequency of said periodic output signal to a DC voltage value; and a detector circuit coupled to said touch circuit, said detector circuit including a microcontroller that receives a plurality of said DC voltage values over time and generates an output signal in response to an intended activation of said touch sensor, said microcontroller configured to monitor said plurality of DC voltage values and to detect an intended activation of said touch sensor based at least in part on a comparison of a ratio of a cumulative deviation of said plurality of DC voltage values from an average voltage value to a scale against a threshold ratio. - View Dependent Claims (35, 36)
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Specification