Capacitive touchpad and toy incorporating the same
First Claim
1. A capacitive touchpad assembly comprising:
- a capacitive touch surface;
a pulse generator configured to provide pulses defining recurring intervals;
a logic-controlled switch for altering a voltage of the capacitive touch surface during each interval until the voltage of the capacitive touch surface reaches a threshold voltage;
a timer configured to measure the time required for the voltage of the capacitive touch surface to reach the threshold voltage in each interval;
an accumulator configured to accumulate the times measured by the timer during a predetermined number of intervals; and
control circuitry configured to produce a signal indicative of the capacitive touch surface being touched where the accumulated time is greater than a predetermined value.
1 Assignment
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Accused Products
Abstract
Capacitive touchpad assemblies, toys including capacitive touchpad assemblies and integral card readers, and methods for detecting contact with a capacitive touch surface are provided. A capacitive touch surface may have a capacity that varies depending on whether it is being contacted by an object such as a human finger. A voltage of the capacitive touch surface may be altered during each of a predetermined number of recurring time intervals. The capacitance of the capacitive touch surface will determine the amount of time required to alter its voltage to a threshold voltage within each time interval. The sum amount of time required for the voltage of the capacitive touch surface to reach the threshold voltage in a predetermined number of time intervals may be used to determine whether the capacitive touch surface is being touched.
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Citations
20 Claims
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1. A capacitive touchpad assembly comprising:
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a capacitive touch surface; a pulse generator configured to provide pulses defining recurring intervals; a logic-controlled switch for altering a voltage of the capacitive touch surface during each interval until the voltage of the capacitive touch surface reaches a threshold voltage; a timer configured to measure the time required for the voltage of the capacitive touch surface to reach the threshold voltage in each interval; an accumulator configured to accumulate the times measured by the timer during a predetermined number of intervals; and control circuitry configured to produce a signal indicative of the capacitive touch surface being touched where the accumulated time is greater than a predetermined value. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A method of detecting contact with a capacitive touch surface comprising:
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providing pulses to define recurring intervals; altering a voltage of the capacitive touch surface during each interval until the voltage of the capacitive touch surface reaches a threshold voltage; measuring the time required for the voltage of the capacitive touch surface to reach the threshold voltage in each interval; accumulating the times measured during a predetermined number of intervals; and indicating that the capacitive touch surface is being touched where the accumulated time is greater than a predetermined value. - View Dependent Claims (10, 11, 12, 13, 14, 15)
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16. A capacitive touchpad assembly comprising:
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a capacitive touchpad; a clock configured to provide recurring time intervals; control circuitry configured to perform the following steps for a predetermined number of time intervals; alter a voltage of the capacitive touchpad until the voltage of the capacitive touchpad reaches a threshold voltage; measure the time required for the voltage of the capacitive touchpad to reach the threshold voltage; accumulate the measured time; wherein upon completion of the predetermined number of time intervals, the control circuitry is further configured to indicate contact with the capacitive touchpad where the accumulated time is greater than a threshold value. - View Dependent Claims (17, 18, 19, 20)
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Specification