Potentiometer state sensing circuit

Claim 2

A circuit for sensing a state of a potentiometer, having a first impedance device and a conductive element that electrically divides said impedance device into first and second ends, comprising, in combination: (a) a second impedance device electrically connected to said conductive element, said second impedance device and said first and second ends of said first impedance device having first and second time constants associated therewith, respectively, (b) means for applying a voltage alternatively across said second impedance device and either end of said first impedance device, and (c) means for measuring the relative values of said first and second time constants, whereby the state of said potentiometer is determined by said relative values.

Claim 3

The circuit of claim 1 wherein said first impedance device comprises a resistive element.

Claim 4

The circuit of claim 1 wherein said first impedance device comprises a capacitive element.

Claim 5

The circuit of claim 1 wherein said first impedance device comprises an inductive element.

Claim 6

A circuit for sensing a state of a potentiometer, having a resistive element and a wiper that electrically divides said resistive element into first and second ends, comprising, in combination: (a) a capacitor having one end electrically connected to said wiper, (b) means for applying a first predetermined voltage to alternately charge said capacitor through said first and second ends of said resistive element, (c) means for detecting when the voltage across said capacitor reaches a second predetermined voltage, (d) means for measuring first and second time intervals, corresponding to said first and second ends, respectively, between application of said first predetermined voltage and detection of said second predetermined voltage, and (e) means for discharging said capacitor during periods of time between said measurements, wherein the state of said potentiometer can be determined from said first and second time intervals.

Claim 7

A circuit for sensing a state of a potentiometer, having a resistive element and a wiper that electrically divides said resistive element into first and second ends, comprising, in combination: (a) a capacitor having one end electrically connected to said wiper, (b) means for applying a first predetermined voltage to alternately charge said capacitor through said first and second ends of said resistive element, (c) means for detecting when the voltage across said capacitor reaches a second predetermined voltage, (d) means for measuring first and second time intervals, corresponding to said first and second ends, respectively, between application of said first predetermined voltage and detection of said second predetermined voltage, and (e) means for discharging said capacitor during periods of time between said measurements, wherein the state of said potentiometer can be determined from said first and second time intervals.

Claim 8

The circuit of claim 5 wherein said potentiometer comprises a linear potentiometer.

Claim 9

The circuit of claim 5 wherein said potentiometer comprises a rotary potentiometer.

Claim 10

The circuit of claim 5 wherein said potentiometer comprises elongated conductive and resistive elements separated by a small gap and juxtaposed substantially co-extensively between substrates, at least one of which is flexible.

Claim 11

The circuit of claim 5 further comprising a current limiting resistor electrically connected between said capacitor and said wiper.

Claim 12

The circuit of claim 5 wherein the value of said current limiting resistor is much smaller than the value of said resistive element.

Claim 13

The circuit of claim 5 wherein said means for applying a voltage comprises an output port of a microprocessor.

Claim 14

The circuit of claim 5 wherein said detecting means comprises an input buffer of a microprocessor.

Claim 15

The circuit of claim 5 wherein said detecting means comprises a Zener diode.

Claim 16

The circuit of claim 5 wherein said detecting means comprises a diac.

Claim 17

The circuit of claim 5 wherein said detecting means comprises a Schmitt trigger.

Claim 18

The circuit of claim 5 wherein said time interval measuring means comprises a digital counter.

Claim 19

The circuit of claim 5 wherein said time interval measuring means comprises a microprocessor.

Claim 20

The circuit of claim 17 wherein said microprocessor is adapted to divide said first time interval by the sum of said first and second time intervals to provide a digital value which corresponds to the state of said potentiometer.

Claim 21

The circuit of claim 18 further comprising means for averaging, over time, a succession of said digital values.

Claim 22

The circuit of claim 5 wherein said discharging means comprises an output port of a microprocessor.

Claim 23

The circuit of claim 5 wherein the state of said potentiometer determines the output of a microprocessor.

Claim 24

The circuit of claim 5 wherein the state of said potentiometer determines the output of a dimming circuit.

Claim 25

The circuit of claim 5 wherein the state of said potentiometer determines the signal output of a wireless transmitter.

Claim 26

A circuit for sensing a state of a plurality of potentiometers, each having a resistive element and a wiper that electrically divides said resistive element into first and second ends, comprising, in combination: (a) a capacitor having one end electrically connected to said wiper of each of said potentiometers, (b) means for applying a first predetermined voltage to alternately charge said capacitor through said first and second ends of said resistive element of a potentiometer selected from said plurality of potentiometers, (c) means for detecting when the voltage across said capacitor reached a second predetermined voltage, (d) means for measuring first and second time intervals, corresponding to said first and second ends of said selected potentiometer, respectively, between application of said first predetermined voltage and detection of said second predetermined voltage, and (e) means for discharging said capacitor during periods of time between said measurements, wherein the state of said selected potentiometer can be determined from said first and second time intervals.

Claim 27

A circuit for sensing a state of a plurality of potentiometers, each having a resistive element and a wiper that electrically divides said resistive element into first and second ends, comprising, in combination: (a) a capacitor having one end electrically connected to said wiper of each of said potentiometers, (b) means for applying a first predetermined voltage to alternately charge said capacitor through said first and second ends of said resistive element of a potentiometer selected from said plurality of potentiometers, (c) means for detecting when the voltage across said capacitor reached a second predetermined voltage, (d) means for measuring first and second time intervals, corresponding to said first and second ends of said selected potentiometer, respectively, between application of said first predetermined voltage and detection of said second predetermined voltage, and (e) means for discharging said capacitor during periods of time between said measurements, wherein the state of said selected potentiometer can be determined from said first and second time intervals.

Claim 28

The circuit of claim 24 wherein at least one of said potentiometers comprises a linear potentiometer.

Claim 29

The circuit of claim 24 wherein at least one of said potentiometers comprises a rotary potentiometer.

Claim 30

The circuit of claim 24 wherein at least one of said potentiometers comprises elongated conductive and resistive elements separated by a small gap and juxtaposed substantially co-extensively between substrates, at least one of which is flexible.

Claim 31

The circuit of claim 24 further comprising a current limiting resistor electrically connected between said capacitor and said wipers.

Claim 32

The circuit of claim 24 wherein said means for applying a voltage comprises an output port of a microprocessor.

Claim 33

The circuit of claim 24 further comprising means for continually selecting said potentiometers in sequential order.

Claim 34

The circuit of claim 24 further comprising means for selecting said potentiometers as they are adjusted.

Claim 35

The circuit of claim 24 wherein said detecting means comprises an input buffer of a microprocessor.

Claim 36

The circuit of claim 24 wherein said detecting means comprises a Zener diode.

Claim 37

The circuit of claim 24 wherein said detecting means comprises a diac.

Claim 38

The circuit of claim 24 wherein said detecting means comprises a Schmitt trigger.

Claim 39

The circuit of claim 24 wherein said time interval measuring means comprises a digital counter.

Claim 40

The circuit of claim 24 wherein said time interval measuring means comprises a microprocessor.

Claim 41

The circuit of claim 37 wherein said microprocessor is adapted to divide said first time interval by the sum of said first and second time intervals to provide a digital value which corresponds to the state of said selected potentiometer.

Claim 42

The circuit of claim 24 wherein the state of said selected potentiometer determines the output of a microprocessor.

Claim 43

The circuit of claim 24 wherein the state of said selected potentiometer determines the output of a dimming circuit.

Claim 44

The circuit of claim 40 wherein at least one of said potentiometers is located remotely from the remaining potentiometers.