Computer keyboard with quantitatively force-sensing keys
First Claim
1. A computer keyboard, comprising:
- a plurality of keys, each key of the plurality having an unpressed condition in which no force is exerted upon the key by a user and a pressed condition in which force is exerted on the key by a user;
a force detection circuit configured toscan each key of the plurality to determine if a scanned key is in a pressed condition,quantify, upon determining that a scanned key is in a pressed condition, the force exerted by a user on said key determined to be in a pressed condition, andproceed, upon determining that a scanned key is not in a pressed condition, to another key of said plurality without quantifying a force exerted on the key determined not to be in a pressed condition;
a first group of conductors;
a second group of conductors positioned in close proximity to the first group of conductors, the first and second groups of conductors forming a plurality of intersections between first group conductors and second group conductors; and
a force sensitive resistive element located between the first group conductor and the second group conductor of each of the plurality of intersections, whereineach of the plurality of intersections corresponds to an associated key of the plurality of keys, each of the associated keys configured to compress the resistive element located at the corresponding intersection upon exertion of force on the associated key,the force detection circuit is configured to quantify force exerted upon each of the associated keys based upon changes in resistance value of the resistive element at each corresponding intersection,the force detection circuit comprises a microprocessor and a voltage divider, andthe microprocessor is configured to place the voltage divider in a first condition when scanning each key of the plurality to determine if a scanned key is in a pressed condition and in a second condition when quantifying the force exerted by a user on a key determined to be in a pressed condition.
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Accused Products
Abstract
A computer keyboard has a grid of conductors forming a plurality of intersections, with force-sensitive resistor (FSR) elements located between the conductors at the intersections. A plurality of keys are located above the intersections and exert force on the conductors and FSR elements during key presses. A resistor network sub-circuit is connected to some of the conductors, and is switchable between low and high resistance values. An Analog to Digital Converter (ADC) is coupled to the resistor network sub-circuit. A microprocessor grounds a conductor and tests another conductor for a threshold voltage level while the resistor network is switched to the high resistance value. The microprocessor switches the resistor network to the low resistance value upon detecting the threshold voltage level and subsequently receives from the ADC a digital value of a voltage on the tested conductor.
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Citations
20 Claims
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1. A computer keyboard, comprising:
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a plurality of keys, each key of the plurality having an unpressed condition in which no force is exerted upon the key by a user and a pressed condition in which force is exerted on the key by a user; a force detection circuit configured to scan each key of the plurality to determine if a scanned key is in a pressed condition, quantify, upon determining that a scanned key is in a pressed condition, the force exerted by a user on said key determined to be in a pressed condition, and proceed, upon determining that a scanned key is not in a pressed condition, to another key of said plurality without quantifying a force exerted on the key determined not to be in a pressed condition; a first group of conductors; a second group of conductors positioned in close proximity to the first group of conductors, the first and second groups of conductors forming a plurality of intersections between first group conductors and second group conductors; and a force sensitive resistive element located between the first group conductor and the second group conductor of each of the plurality of intersections, wherein each of the plurality of intersections corresponds to an associated key of the plurality of keys, each of the associated keys configured to compress the resistive element located at the corresponding intersection upon exertion of force on the associated key, the force detection circuit is configured to quantify force exerted upon each of the associated keys based upon changes in resistance value of the resistive element at each corresponding intersection, the force detection circuit comprises a microprocessor and a voltage divider, and the microprocessor is configured to place the voltage divider in a first condition when scanning each key of the plurality to determine if a scanned key is in a pressed condition and in a second condition when quantifying the force exerted by a user on a key determined to be in a pressed condition. - View Dependent Claims (2, 3, 4, 5)
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6. A computer keyboard, comprising
a grid of first group conductors and second group conductors, the first and second group conductors forming a plurality of intersections; -
a force-sensitive resistive element at each intersection of the plurality located between one of the conductors of the first group and one of the conductors of the second group forming said intersection; a plurality of keys located above the plurality of intersections, each key being associated with one intersection and configured to exert force on the conductors and force-sensitive resistive element of the associated intersection during a key press; a microprocessor having a plurality of first group conductor pins each in contact with one of the first group conductors and a plurality of second group conductor pins each in contact with one of the second group conductors; a sub-circuit connected to at least one of the second group conductors, the sub-circuit having a resistor network switchable by the microprocessor between a low resistance value and a high resistance value; and an Analog to Digital Converter (ADC) coupled to the sub-circuit and to the microprocessor. - View Dependent Claims (7, 8, 9, 10, 11, 12, 13, 14)
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15. A microprocessor having preprogrammed instructions for performing steps comprising:
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placing a detection circuit in a first state in which the detection circuit is configured to identity a pressed key of a keyboard; selecting, while in the first state, a conductor pin from a group of conductor pins; testing, while in the first state, the selected conductor pin for a threshold voltage level; upon detecting the threshold voltage level on the selected conductor pin, placing the detection circuit in a second state by altering the resistance of a resistance network; when in the second state, receiving a digital value for a voltage on the selected conductor pin, the digital voltage value representing an amount of force applied to the pressed key; scanning the keyboard for presses of additional keys by testing for a threshold voltage level with regard to each of the additional keys when the detection circuit is in the first state; and placing the detection circuit in the second state and receiving additional digital voltage values upon detection of threshold voltages with regard to the additional keys. - View Dependent Claims (16, 17, 18, 19, 20)
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Specification