Methods and apparatus for water detection using a capacitive sensor

1. A door handle apparatus integrated within a vehicle door, comprising:

a pop-out door handle comprising a first outer surface that is flush with a second outer surface of the vehicle door;

a first sensor integrated within the pop-out door handle, wherein the first sensor is directly adjacent to the first outer surface and comprises a first electrode and a second electrode, and wherein the first electrode is capable of forming a first electric field with the second electrode; and

a second sensor integrated within one of the pop-out door handle and the vehicle door, wherein the second sensor is positioned above the first sensor and comprises a third electrode and a fourth electrode, and wherein the third electrode is capable of forming a second electric field with the fourth electrode.

2. The door handle apparatus according to claim 1 , wherein the first sensor is positioned between a top edge of the pop-out door handle and a bottom edge of the pop-out door handle.

3. The door handle apparatus according to claim 1 , wherein:

the second sensor comprises a ring-shape that surrounds the first sensor; and

the third and fourth electrodes are equally spaced relative to each other.

4. The door handle apparatus according to claim 1 , wherein:

the first electrode comprises a comb-shape;

the second electrode comprises the comb-shape; and

the first and second electrodes are interleaved with each other.

5. The door handle apparatus according to claim 1 , further comprising a separator electrode positioned between the first sensor and the second sensor and having a reference potential.

6. The door handle apparatus according to claim 1 , wherein the first and second electrodes are equally spaced relative to each other and arranged in a spiral shape.

7. The door handle apparatus according to claim 1 , further comprising:

a third sensor integrated within the pop-out door handle, and comprising a fifth electrode and a sixth electrode, wherein the fifth electrode is capable of forming a third electric field with the sixth electrode, and wherein the third sensor is positioned directly below the first sensor.

8. A method for detecting water flow across a sensor system, comprising:

measuring a first capacitance of a first planar sensor, wherein the first sensor comprises a first electrode and a second electrode, wherein the first electrode forms a first electric field with the second electrode;

measuring a second capacitance of a second planar sensor, wherein the second sensor comprises a third electrode and a fourth electrode, wherein the third electrode forms a second electric field with the fourth electrode; and wherein the first and second sensors are arranged along a same vertical plane, and the second electrode is positioned above the first electrode;

detecting a change in the first capacitance;

detecting a change in the second capacitance; and

detecting water flowing vertically across the second electrode and the first electrode based on a timing of the change in the first capacitance with respect to a timing of the change in the second capacitance.

9. The method according to claim 8 , wherein water flow is detected if the change in the second capacitance occurs earlier in time than the change in the first capacitance.

10. The method according to claim 8 , wherein a direction of the water flow is downward.

11. A sensor system integrated within an apparatus having a waterproof outer cover, comprising:

a first mutual capacitive sensor integrated within the apparatus and positioned directly adjacent to the outer cover, and comprising a first electrode and a second electrode, wherein the first electrode is capable of forming a first electric field with the second electrode;

a second mutual capacitive sensor integrated within the apparatus and positioned directly adjacent to the outer cover and above the first mutual capacitive sensor, and comprising a third electrode and a fourth electrode, wherein the third electrode is capable of forming a second electric field with the fourth electrode;

a sensing circuit connected to the first and second mutual capacitive sensors and configured to measure a change in the first and second electric fields; and

a microcontroller connected to the sensing circuit and configured to generate a control signal according to the measured change in the first and second electric fields.

12. The sensor system according to claim 11 , wherein:

the second mutual capacitive sensor comprises a ring-shape that surrounds the first mutual capacitive sensor; and

the third and fourth electrodes are equally spaced relative to each other.

13. The sensor system according to claim 11 , wherein:

the first electrode comprises a comb-shape;

the second electrode comprises the comb-shape; and

the first and second electrodes are interleaved with each other.

14. The sensor system according to claim 11 , further comprising a ground electrode positioned between the first and second mutual capacitive sensors.

15. The sensor system according to claim 11 , wherein the first and second electrodes are equally spaced relative to each other and arranged in a spiral shape.

16. The sensor system according to claim 11 , further comprising a third sensor integrated within the apparatus, and comprising a fifth electrode and a sixth electrode, wherein the fifth electrode is capable of forming a third electric field with the sixth electrode; and wherein the third sensor is positioned directly adjacent to the outer cover and below the first mutual capacitive sensor.

17. The sensor system according to claim 11 , wherein the microcontroller is configured to detect water flowing from the second electrode to the first electrode.

18. The sensor system according to claim 11 , wherein the microcontroller is configured to detect water flow based on a timing of the change in the first electric field with respect to a timing of the change in the second electric field.

19. The sensor system according to claim 18 , wherein the microcontroller detects water flow if the change in the second electric field occurs earlier in time than the change in the first electric field.