Capacitive position sensor
A capacitive touch sensor is provided having sensing path for setting a color parameter to a desired value within a range, the color parameter being color hue, color saturation or color temperature. The sensor includes a sensing element having a sensing path, a terminal connecting the sensing element to a sensing channel, and a processor configured to interpret a signal indicative of a capacitance of the terminal. The processor has a first mode configured to set a parameter to a desired value. The desired value is related to a first position of an object sensed along the sensing path and a range of parameter values mapped to a length of the sensing path. A second mode adjusts the parameter based on a displacement of the object along the sensing path.
1. A capacitive position sensor for setting a parameter or function to a desired value in a range of parameter values by determining the position of an object on a capacitive position sensor, the capacitive position sensor comprising:
a sensing element comprising a sensing path;
at least one terminal connected to the sensing element;
at least one sensing channel connected to the at least one terminal in which the sensing channel is operable to generate a signal indicative of capacitance between the terminal and a system ground;
means to determine a position of an object on the sensing element;
means to further refine the position of the object corresponding to a value in the range of parameter values; and
a processor operable to interpret and process the signal to determine a position of an object on the sensing path, the processor being configured to provide a first mode of the capacitive position sensor in which the range of parameter values is mapped onto the sensing path and to set a parameter to approximately the desired value by a touch of the sensing path at a first point, and a second mode in which displacement of the object on the sensing element adjusts the parameter from the value initially set in the first mode, wherein the processor is configured to switch from the first mode to the second mode responsive to capacitive coupling caused by moving displacement of the object along the sensing path in relation to the first point of touch, and wherein the parameter being controlled by the capacitive position sensor is an aspect of color,
wherein the aspect of color is selected from color hue, color saturation, and color temperature.
2. The sensor of claim 1 , wherein the sensing path is formed as a closed loop.
3. The sensor of claim 1 , wherein the processor requires a displacement of the object to exceed a minimum threshold value in order to initiate a change in mode of the processor from the first mode to the second mode.
4. The sensor of claim 1 , wherein, in the second mode, the processor effects an incremental change in the parameter value when it is sensed that the object has moved along the sensing path by a pre-determined threshold displacement.
5. The sensor of claim 1 , wherein, in the second mode, the processor changes the parameter value by a number of units based on the number of times the object displacement along the sensing path is sensed to have exceeded the pre-determined threshold displacement.
6. The sensor of claim 1 , wherein, in the second mode, the processor maps a narrower sub-range of the range of parameter values onto the sensing path around the value of the parameter initially set in the first mode.
7. The sensor of claim 1 , wherein the processor is further configured such that if a release of touch from the sensing element in the second mode followed by a subsequent re-touching of the sensing element is sensed, then the first mode is activated.
8. The sensor of claim 1 , wherein the processor is configured to allow selection of the parameter prior to use of the capacitive position sensor.
9. A control panel of an electronic appliance incorporating a capacitive position sensor according to claim 1 .
10. An electronic appliance having a control panel incorporating a capacitive position sensor according to claim 1 .
11. The electronic appliance of claim 10 selected from a cooking oven, microwave oven, television, washing machine, MP3 player, mobile phone, and multimedia device.
12. A method for setting a parameter to a desired value in a range of parameter values by determining the position of an object on a capacitive position, sensor, the capacitive position sensor comprising: a sensing element comprising a sensing path; at least one terminal connected to the sensing element; at least one sensing channel connected to the at least one terminal in which the sensing channel is operable to generate a signal indicative of capacitance between the terminal and a system ground; means to determine a position of an object on the sensing element; and means to further refine the position of the object corresponding to a value in the range of parameter or function values, the method comprising:
in a first mode of the capacitive position sensor in which the range of parameter values is mapped onto the sensing path bringing an object into proximity with the sensing element at a first point so as to determine a position of the object and thereby initially set the parameter to approximately the desired value;
initiating a change in mode of the sensor from the first mode to a second mode responsive to capacitive coupling caused by moving displacement of the object along the sensing path in relation to the first point of touch of the object on the sensing element;
in the second mode displacing the object on the sensing element to adjust the parameter from the value initially set to the desired value; and
processing the signal to determine the parameter value,
wherein the parameter being controlled by the capacitive position sensor is an aspect of color selected from the group consisting of color hue, color saturation, and color temperature.
13. The method of claim 12 , wherein the sensing path is formed as a closed loop.
14. The method of claim 12 , wherein said moving displacement is required to exceed a minimum threshold value in order to initiate a change in mode of the sensor from the first mode to the second mode.
15. The method of claim 12 , wherein, in the second mode, an incremental change in the parameter value is effected by the object moving along the sensing path by a pre-determined threshold displacement.
16. The method of claim 12 , wherein, in the second mode, the parameter value is changed by a number of units based on the number of times the object displacement along the sensing path exceeds the pre-determined threshold displacement.
17. The method of claim 12 , wherein, in the second mode, a narrower subrange of the range of parameter values is mapped onto the sensing path around the value of the parameter or function initially set in the first mode.
18. The method of claim 12 , wherein releasing touch from the sensing element in the second mode and then re-touching the sensing element causes the first mode to be activated again.
19. The method of claim 12 , wherein the parameter is selectable prior to use of the capacitive position sensor.
20. A sensor comprising:
a sensing element comprising a sensing path having a length;
at least one sensing channel operable to generate a signal indicative of capacitance between the sensing path and a system ground;
a processor having a first mode and a second mode, the processor configured to determine a first position of an object along the sensing path using the signal and to set a parameter to an initial value in the first mode, wherein the initial value is a function of the first position along the sensing path and to a range of parameter values associated with the length of the sensing path, the processor further configured to adjust the parameter in a second mode in response to a displacement of the object along the sensing path from the first position, wherein the processor is configured to switch from the first mode to the second mode when the signal indicates displacement of the object proximate the sensing element and along the sensing path, and
wherein the processor uses the value of the parameter value to control at least one aspect of color selected from the group consisting of color hue, color saturation, and color temperature.
21. The sensor of claim 20 , wherein the sensing path is formed as a closed loop.
22. The sensor of claim 21 , wherein the sensing path is curved.
23. The sensor of claim 20 , wherein the processor is configured to change from the first mode to the second mode when the displacement of the object exceeds a minimum threshold displacement.
24. The sensor of claim 20 , wherein, in the second mode, the processor maps a sub-range of parameter values onto the sensing path, the sub-range of parameter values substantially centered about the initial value set in the first mode.
25. The sensor of claim 20 , wherein, in the second mode, the processor is configured to incrementally change the parameter value when the signal indicates that the object has moved along the sensing path by a pre-determined threshold displacement from the first point.