An example method includes measuring a capacitance variation of a first conductive element and a capacitance variation of a second conductive element. The example method includes calculating a centroid position through the measured capacitance variation of the first conductive element and the measured capacitance variation of the second conductive element. A conductive sub-element of the first conductive element may be interleaved with a conductive sub-element of the second conductive element. The conductive sub-element of the first conductive element and the conductive sub-element of the second conductive element may each have a varying width.
1. An apparatus comprising:
a first conductive element of a capacitive touch sensor having at least one conductive sub-element;
a second conductive element of the capacitive touch sensor having at least one conductive sub-element,
the at least one conductive sub-element of the first conductive element interleaved with the at least one conductive sub-element of the second conductive element, the at least one conductive sub-element of the first conductive element and the at least one conductive sub-element of the second conductive element each having a varying width from a first end of the capacitive touch sensor to a second end of the capacitive touch sensor; and
a processing device coupled with the capacitive touch sensor, the processing device configured to calculate a centroid position of a conductive object through a capacitance variation of the first conductive element and a capacitance variation of the second conductive element, wherein the calculation of the centroid position includes comparing the capacitance variation of the first conductive element with a sum of the capacitance variation of the first conductive element and the capacitance variation of the second conductive element.
2. The apparatus of claim 1 , wherein the width of the at least one conductive sub-element of the first conductive element gradually decreases from the first end of the capacitive touch sensor to the second end of the capacitive touch sensor, and the width of the at least one conductive sub-element of the second conductive element gradually increases from the first end of the capacitive touch sensor to the second end of the capacitive touch sensor.
3. The apparatus of claim 1 , wherein the at least one conductive sub-element of the first conductive element and the at least one conductive sub-element of the second conductive element are in a shape of a triangle.
4. The apparatus of claim 1 , wherein the first conductive element includes a first plurality of conductive sub-elements and the second conductive element includes a second plurality of conductive sub-elements, wherein the first plurality of conductive sub-elements are alternated with the second plurality of conductive sub-elements.
5. The apparatus of claim 1 , wherein a first end of the at least one conductive sub-element of the first conductive element is adjacent to a first end of the at least one conductive sub-element of the second conductive element.
6. The apparatus of claim 1 , wherein the first conductive element and the second conductive element are in a same plane.
7. The apparatus of claim 1 , wherein the centroid position is P cen , with P cen =d2/(d1+d2)×N res , wherein d1 is the capacitance variation of the first conductive element, d2 is the capacitance variation of the second conductive element, and N res is a resolution of the capacitive touch sensor.
8. The apparatus of claim 1 , comprising a substrate having a first side and a second side, wherein the first conductive element and the second conductive element are formed on the first side of the substrate, and the processing device is coupled to the second side of the substrate.
9. The apparatus of claim 8 , wherein the first conductive element is coupled to a first capacitive sensing pin of the processing device, and the second conductive element is coupled to a second capacitive sensing pin of the processing device.
10. The apparatus of claim 8 , wherein the first conductive element and the second conductive element form a single layer on the first side of the substrate.
11. A method comprising:
measuring a capacitance variation of a first conductive element, the first conductive element including at least one conductive sub-element;
measuring a capacitance variation of a second conductive element, the second conductive element including at least one conductive sub-element,
the at least one conductive sub-element of the first conductive element interleaved with the at least one conductive sub-element of the second conductive element, the at least one conductive sub-element of the first conductive element and the at least one conductive sub-element of the second conductive element each having a varying width; and
calculating a position of a conductive object through the measured capacitance variation of the first conductive element and the measured capacitance variation of the second conductive element, wherein the calculating of the position includes comparing the measured capacitance variation of the first conductive element with a sum of the measured capacitance variation of the first conductive element and the measured capacitance variation of the second conductive element.
12. The method of claim 11 , wherein the calculating of the position includes calculating P cen , with P cen =d2/(d1+d2)×N res , wherein d1 is the capacitance variation of the first conductive element, d2 is the capacitance variation of the second conductive element, and N res is a resolution of a capacitive touch sensor including the first conductive element and the second conductive element.
13. The method of claim 11 , wherein the measured capacitance variation of the first conductive element depends on the width of the at least one conductive sub-element of the first conductive element, wherein the width of the at least one conductive sub-element of the first conductive element gradually decreases from a first end of the first conductive element to a second end of the first conductive element.
14. The method of claim 13 , wherein the measured capacitance variation of the second conductive element depends on the width of the at least one conductive sub-element of the second conductive element, wherein the width of the at least one conductive sub-element of the second conductive element gradually increases from a first end of the second conductive element to a second end of the second conductive element.
15. A system comprising:
a capacitive touch sensor including:
a first conductive element having at least one conductive sub-element; and
a second conductive element having at least one conductive sub-element, the at least one conductive sub-element of the first conductive element interleaved with the at least one conductive sub-element of the second conductive element, the at least one conductive sub-element of the first conductive element and the at least one conductive sub-element of the second conductive element each having a varying width from a first end of the capacitive touch sensor to a second end of the capacitive touch sensor; and
a capacitance sensor coupled with the capacitive touch sensor, the capacitance sensor configured to measure a capacitance variation of the first conductive element and measure a capacitance variation of the second conductive element; and
a processing device coupled with the capacitive touch sensor, the processing device configured to calculate a centroid position of a conductive object through the capacitance variation of the first conductive element and the capacitance variation of the second conductive element, wherein the calculation of the centroid position includes comparing the capacitance variation of the first conductive element with a sum of the capacitance variation of the first conductive element and the capacitance variation of the second conductive element.
16. The system of claim 15 , further comprising a communication interface configured to communicate the centroid position with a host, the host configured to use the centroid position in at least one of an adjustment operation, a scrolling operation, and a gesture operation.
17. The system of claim 15 , wherein the capacitance sensor includes a relaxation oscillator coupled with the first conductive element and the second conductive element through one or more analog signal interface, the relaxation oscillator configured to measure the capacitance variation of the first conductive element and measure the capacitance variation of the second conductive element.
18. The system of claim 15 , wherein the capacitive touch sensor includes a touch sensor slider, wherein each of the first conductive element and the second conductive element comprise a switch of the touch sensor slider.