Capacitive sensitive switch method and system
First Claim
1. A capacitive sensitive switch, which comprises:
- plural capacitive sensitive touch pads;
plural resistors each electrically connected to one of said plural capacitive sensitive touch pads and to a preferred voltage state;
a single programmable microcontroller having an addressable I/O port with plural I/O pins, each of said plural I/O pins being in electrical connection with one of said plural capacitive sensitive touch pads and one of said plural resistors, for setting said plural capacitive sensitive touch pads simultaneously to predetermined voltages, and for transitioning said plural capacitive sensitive touch pads in a staggered manner to compress interation intervals over which said plural capacitive sensitive touch pads undergo logic level transitions, and for measuring logic levels of said plural capacitive sensitive touch pads simultaneously to detect a touch.
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Accused Products
Abstract
A touch sensor switch that responds to touching, or even to the proximity of an object, is disclosed. The switch includes a number of capacitance elements, or touch pads, that produce an effective capacitance dependent upon the physical proximity of the object. A microcontroller under control of a program stored in a read-only memory causes its I/O port to set a transient voltage on each capacitance element as a logic level. Each transient voltage is at variance with the capacitive element'"'"'s preferred voltage level. The program then reads the I/O port, and hence the logic levels of the capacitance elements, as the capacitive elements revert to their preferred voltage levels, and calculates the proximity of the object, or touching, from relationships among recorded signals. The circuit may also be embodied in an application specific integrated circuit.
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Citations
25 Claims
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1. A capacitive sensitive switch, which comprises:
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plural capacitive sensitive touch pads; plural resistors each electrically connected to one of said plural capacitive sensitive touch pads and to a preferred voltage state; a single programmable microcontroller having an addressable I/O port with plural I/O pins, each of said plural I/O pins being in electrical connection with one of said plural capacitive sensitive touch pads and one of said plural resistors, for setting said plural capacitive sensitive touch pads simultaneously to predetermined voltages, and for transitioning said plural capacitive sensitive touch pads in a staggered manner to compress interation intervals over which said plural capacitive sensitive touch pads undergo logic level transitions, and for measuring logic levels of said plural capacitive sensitive touch pads simultaneously to detect a touch. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A capacitive sensitive switch, which comprises:
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plural interdigitated capacitive sensitive touch pads, with adjacent ones of said plural interdigitated capacitive sensitive touch pads being oppositely charged; plural resistors each electrically connected to one of said plural interdigitated capacitive sensitive touch pads and to a preferred voltage state; and a single programmable microcontroller having an addressable I/O port with plural I/O pins, each of said plural I/O pins being in electrical connection with one of said plural interdigitated capacitive sensitive touch pads and one of said plural resistors, for charging adjacent ones of said plural interdigitated capacitive sensitive touch pads simultaneously in an opposite direction for improved resolution in identifying a touching of one of said plural interdigitated capacitive sensitive touch pads, and for discharging said plural interdigitated capacitive sensitive touch pads simultaneously, and for measuring logic levels of said plural interdigitated capacitive sensitive touch pads simultaneously to detect a touch.
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8. A capacitive sensitive switch, which comprises:
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plural capacitive sensitive touch pads; plural resistors each electrically connected to one of said plural capacitive sensitive touch pads and to a preferred voltage state; a RAM memory; and a single programmable microcontroller having an addressable I/O port with plural I/O pins, each of said plural I/O pins being in electrical connection with one of said plural capacitive sensitive touch pads and one of said plural resistors, for setting differing logic levels on said plural capacitive sensitive touch pads simultaneously, and for transitioning said plural capacitive sensitive touch pads simultaneously, and for measuring logic levels of said plural capacitive sensitive touch pads simultaneously and recording only logic level transitions and transition iteration numbers to detect a touch, thereby reducing use of said RAM memory.
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9. A capacitive sensitive switch, which comprises:
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plural capacitive sensitive touch pads; plural resistors each electrically connected to one of said plural capacitive sensitive touch pads and to a preferred voltage state; a single programmable microcontroller having an addressable I/O port with plural I/O pins, each of said plural I/O pins being in electrical connection with one of said plural capacitive sensitive touch pads and one of said plural resistors, for setting same logic level on said plural capacitive sensitive touch pads simultaneously, and for transitioning said plural capacitive sensitive touch pads simultaneously, and for measuring logic levels of said plural capacitive sensitive touch pads simultaneously to detect a touch; and a digital I/O transceiver electrically connected to and positioned between said single programmable microcontroller and said plural capacitive sensitive touch pads to accommodate multiple uses of said plural I/O pins, and to shorten trace lengths and thereby reduce charge coupling associated with discharge of said plural capacitive sensitive touch pads. - View Dependent Claims (10)
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11. A capacitive sensitive switch, which comprises:
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plural groups of capacitive sensitive touch pads having rounded corners; plural groups of resistors each resistor of said plural groups of resistors being electrically connected to one of said plural groups of capacitive sensitive touch pads, and each resistor of said plural groups of resistors connected to a preferred voltage state; a single programmable microcontroller having plural addressable I/O ports, each of said plural addressable I/O ports having plural I/O pins in electrical connection with one of said plural groups of resistors and one of said plural groups of capacitive sensitive touch pads, for sequentially addressing each of said plural addressable I/O ports to charge each capacitive sensitive touch pad in an associated one of said plural groups of capacitive sensitive touch pads simultaneously, and for discharging said each capacitive sensitive touch pad in said plural groups of capacitive sensitive touch pads simultaneously to avoid coupling of residual charges among capacitive sensitive touch pads within said plural groups of capacitive sensitive touch pads, while measuring logic levels of all capacitive sensitive touch pads in an associated one of said plural groups of capacitive sensitive touch pads simultaneously to detect a touch.
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12. A method of operating a capacitive sensitive switch having a plurality of capacitive sensitive elements, comprising the steps of:
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setting individual predetermined logic levels simultaneously on each of said plurality of capacitive sensitive elements which is different from individual preferred logic levels associated with each of said plurality of capacitive sensitive elements; reading current logic levels of said plurality of capacitive sensitive elements as a logic level set for a predetermined number of iterations, each of said predetermined number of iterations having an associated iteration number; starting each of said plurality of capacitive sensitive elements to transition to an associated preferred logic level at a same one of said predetermined number of iterations, said same one chosen to permit said plurality of capacitive sensitive elements to transition to their respective preferred logic levels simultaneously in the absence of a touch; and comparing a first associated iteration number at which one of said plurality of capacitive sensitive elements transitions from its preferred logic level with a second associated iteration number for said same one, and issuing a touch or no touch decision for each of said plurality of capacitive sensitive elements depending upon whether a difference between said first associated iteration number and said second associated iteration number exceeds a predetermined threshold number. - View Dependent Claims (13, 14, 15, 16, 17, 18)
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19. A method for determining inputs by touch, the method comprising the steps of:
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interfacing a first capacitive sensitive element and a microcontroller with a first trace, the first trace having a first trace capacitance; interfacing a second capacitive sensitive element and the microcontroller with a second trace, the second trace having a second trace capacitance; determining whether a touch to the first or the second capacitive sensitive element creates a change of effective capacitance for the first or the second capacitive sensitive element by performing the steps of; transitioning the capacitive sensitive elements from a first voltage state to a second voltage state, compensating for the change of effective capacitance of the first and second capacitive sensitive elements induced by the first and second trace capacitances, and measuring the voltage of the first and second capacitive sensitive elements at plural iterations to determine whether the effective capacitance of the first or second capacitive sensitive element corresponds to the effective capacitance associated with a touch. - View Dependent Claims (20, 21, 22, 23, 24, 25)
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Specification