Proximity switch having learned sensitivity and method therefor

• US 8,975,903 B2
• Filed: 06/09/2011
• Issued: 03/10/2015
• Est. Priority Date: 06/09/2011
• Status: Active Grant

• Current Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Original Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Inventors: Salter, Stuart C., Buttolo, Pietro, Gardner, Cornel Lewis, Goodson, Thomas Lee
• Primary Examiner(s): Phan, Huy Q
• Assistant Examiner(s): Rhodes-Vivour, Temilade S
• Application Number:
  US13/157,028
• Publication Number:
  US 20120312676A1
• Time in Patent Office: 1,370 Days
• Field of Search: 324/457, 324/658, 324679-690, 340/407.02, 345/173
• US Class Current: 324/681
• CPC Class Codes: E05Y 2400/852 Sensors
• CPC Class Codes: E05Y 2400/86 by hand
• CPC Class Codes: E05Y 2900/50 for vehicles
• CPC Class Codes: H03K 17/955 using a capacitive detector
• CPC Class Codes: H03K 2217/94026 Automatic threshold calibration; e.g. threshold automatically adapts to ambient conditions or follows variation of input
• CPC Class Codes: H03K 2217/960705 Safety of capacitive touch and proximity switches, e.g. increasing reliability, fail-safe

Abstract

A vehicle proximity switch and method are provided having learned sensitivity control. The switch includes a proximity sensor, such as a capacitive sensor, installed in a vehicle and providing a sense activation field. Also included is sense control circuitry processing the activation field to sense user activation of the switch by comparing the activation field to a threshold. The switch further includes sensitivity control circuitry learning a user sensitivity based on user activation of a sensor and controlling the sensitivity of one or more proximity switches.

Claims

1. A proximity switch having learned sensitivity control comprising:

one or more proximity sensors providing a sense activation field;

sense control circuitry processing the activation field to sense user activation of the switch by comparing the activation field to a threshold;

a dedicated sensitivity capacitive sensor; and

sensitivity control circuitry sensing use of a glove on the user, learning user sensitivity based on user activation of the sensitivity capacitive sensor and controlling the sensitivity of the switch based on the learned user sensitivity, wherein the one or more proximity sensors each comprises a capacitive sensor, wherein the sensitivity of the switch is controlled by adjusting burst length of a signal applied to the capacitive sensor, wherein the burst length is increased when a peak signal associated with the activation field exceeds the threshold by less than a first count value, and wherein the burst length is decreased when the peak signal exceeds the threshold by at least a second count value.

2. The proximity switch of claim 1, wherein the proximity switch is installed in a vehicle for use by a passenger in the vehicle.

3. The proximity switch of claim 1, wherein the sensitivity control circuitry performs a learning routine upon activation of the sensor.

4. The proximity switch of claim 1 further comprising a temperature sensor sensing temperature, wherein the sensitivity of the proximity switch is further controlled based on the sensed temperature.

5. The proximity switch of claim 1 further comprising an output for providing an output signal to control a device.

6. The proximity switch of claim 1, wherein the dedicated sensitivity capacitive sensor is separate from the one or more proximity sensors.

7. A vehicle capacitive switch having learned sensitivity control comprising:

a capacitive sensor installed in a vehicle and providing a sense activation field;

sense control circuitry processing the activation field to sense user activation of the switch by comparing the activation field to a threshold; and

sensitivity control circuitry sensing use of a glove on the user, learning user sensitivity based on user activation of a sensitivity capacitive sensor and adjusting burst length of a signal applied to the capacitive sensor to control sensitivity of the capacitive switch based on the learned user sensitivity, wherein the burst length is increased when a peak signal associated with the activation field exceeds the threshold by less than a first count value, and wherein the burst length is decreased when the peak signal exceeds the threshold by at least a second count value.

8. The capacitive switch of claim 7 further comprising an output for providing an output signal to a control device.

9. The capacitive switch of claim 7, wherein the sensitivity sensor comprises a dedicated sensitivity sensor that is separate from the capacitive sensor.

10. A method of sensing user proximity with learned sensitivity control, said method comprising:

providing a sense activation field with a proximity sensor;

processing the sense activation field to sense user activation of the proximity sensor by comparing the sense activation field to a threshold;

sensing use of a glove on the user;

learning user sensitivity based on activation of a dedicated sensitivity capacitive sensor that is separate from the proximity sensor; and

adjusting sensitivity of the proximity sensor based on the learned user sensitivity, wherein the proximity sensor comprises a capacitive sensor, wherein the sensitivity is adjusted by controlling burst length of an electrical signal applied to the capacitive sensor, and wherein the burst length is increased when a peak signal associated with the activation field exceeds the threshold by less than a first count value, and wherein the burst length is decreased when the peak signal exceeds the threshold by at least a second count value.

11. The method of claim 10, wherein the proximity sensor is installed in a vehicle for use by a passenger in the vehicle.

12. The method of claim 10, wherein a learning routine is executed by control circuitry upon activation of the sensitivity sensor.

13. The method of claim 10 further comprising a step of outputting a control signal based on the comparison to control a device.