Membrane digital analog switches

Patent metadata

Field	Value
Publication number	US-2020343902-A1
Application number	US-201916724910-A
Country	US
Kind code	A1
Filing date	Dec 23, 2019
Priority date	Apr 26, 2019
Publication date	Oct 29, 2020
Grant date	—

Abstract

A membrane digital analog switch includes an input button surface adapted to receive an input pressure from a user, and a digital switch positioned below the input button surface to generate a digital switch activation signal when the received pressure on the input button surface is greater than or equal to a specified digital pressure threshold. The membrane digital analog switch also includes an analog switch adapted to generate an analog switch activation signal when the received pressure on the input button surface is greater than or equal to a specified analog pressure threshold. The specified analog pressure threshold is greater than the specified digital pressure threshold, the digital switch activation signal is a binary digital signal, and the analog switch activation signal is variable and corresponds to an analog sensed value of the received pressure on the input button surface.

First claim

What is claimed is:

1 . A switch comprising:
an input button surface adapted to receive an input pressure from a user; a digital switch adapted to generate a digital switch activation signal when the received pressure on the input button surface is greater than or equal to a specified digital pressure threshold; and an analog switch adapted to generate an analog switch activation signal when the received pressure on the input button surface is greater than or equal to a specified analog pressure threshold; wherein the specified analog pressure threshold is greater than the specified digital pressure threshold.

2 . The switch of claim 1 , wherein:
the digital switch activation signal is a binary digital signal; and/or the analog switch activation signal is variable and corresponds to an analog sensed value of the received pressure on the input button surface; and/or the digital switch is positioned below the input button surface.

3 . The switch of claim 1 , wherein the analog switch includes a force-sensing resistor.

4 . The switch of claim 3 , wherein the force-sensing resistor includes a non-linear resistance characteristic where a resistance of the force-sensing resistor decreases non-linearly as pressure on the input button surface is increased.

5 . The switch of claim 4 , further comprising a controller configured to measure the analog switch activation signal, and to determine the received input pressure on the input button surface according to the measured analog switch activation signal.

6 . The switch of claim 5 , wherein the controller is configured to determine a change in slope of the analog switch activation signal, and compare the change in slope to the non-linear resistance characteristic of the force-sensing resistor to determine the received input pressure on the input button surface.

7 . The switch of claim 3 , wherein the analog switch including the force-sensing resistor is positioned below the digital switch with respect to the input button surface.

8 . The switch of claim 3 , wherein:
the digital switch is a first digital switch; the switch further comprises a second digital switch positioned below the first digital switch with respect to the input button surface; and the analog switch including the force-sensing resistor is coupled in series with the second digital switch.

9 . The switch of claim 8 , further comprising a controller configured to:
detect a second digital switch activation signal when the second digital switch is closed; measure an initial resistance of the force-sensing resistor in response to detecting the second digital switch activation signal; and set the measured initial resistance as a calibration value for measuring an analog force-sensing resistor signal corresponding to the resistance of the force-sensing resistor to determine the received input pressure on the input button surface.

10 . The switch of claim 1 , wherein:
the input button surface and the digital switch define a tactile switch including a metal dome, the input button surface comprises an overlay contacting a first side of the metal dome, and a second side of the metal dome opposite the first side is positioned to contact an electrical conductor of the digital switch in response to the received pressure on the overlay contacting the first side of the metal dome; or the input button surface and the digital switch define a non-tactile switch including an electrically-conductive pad, the input button surface comprises an overlay contacting a first side of the electrically-conductive pad, and a second side of the electrically-conductive pad opposite the first side is positioned to contact an electrical conductor of the digital switch in response to the received pressure on the overlay contacting the first side of the electrically-conductive pad; or the input button surface and the digital switch define a rocker switch.

11 . The switch of claim 1 , further comprising a controller configured to:
determine a positive on step in response to receiving the digital switch activation signal; and in response to determining the positive on step, to implement one or more analog functions according to the received analog switch activation signal.

12 . The switch of claim 11 , wherein the one or more analog functions include at least one or more of:
controlling a speed or flow rate of a machine; and/or controlling a speed of a crane or a vehicle; and/or controlling a flow rate of a concrete pump or a pressure washer.

13 . The switch of claim 1 , wherein the switch is a membrane digital analog switch.

14 . A keypad including at least one switch according to claim 1 .

15 . A keypad comprising one or more switches, each said switch including:
an input button surface adapted to receive an input pressure from a user; a digital switch adapted to generate a digital switch activation signal when the received pressure on the input button surface is greater than or equal to a specified digital pressure threshold; and an analog switch adapted to generate an analog switch activation signal when the received pressure on the input button surface is greater than or equal to a specified analog pressure threshold; wherein the specified analog pressure threshold is greater than the specified digital pressure threshold.

16 . The keypad of claim 15 , wherein:
the digital switch activation signal is a binary digital signal; and/or the analog switch activation signal is variable and corresponds to an analog sensed value of the received pressure on the input button surface.

17 . A method of operating a switch including an input button surface, a digital switch, and an analog switch, the method comprising:
receiving, at the input button surface, an input pressure from a user; generating, by the digital switch, a digital switch activation signal when the received pressure on the input button surface is greater than or equal to a specified digital pressure threshold; and generating, by the analog switch, an analog switch activation signal when the received pressure on the input button surface is greater than or equal to a specified analog pressure threshold; wherein the specified analog pressure threshold is greater than the specified digital analog pressure threshold.

18 . The method of claim 17 , wherein:
the digital switch activation signal is a binary digital signal; and/or the analog switch activation signal is variable and corresponds to an analog sensed value of the received pressure on the input button surface.

19 . The method of claim 17 , further comprising implementing one or more analog functions of a machine according to the analog switch activation signal, only after the digital switch activation signal is generated.

20 . The method of claim 17 , wherein:
the analog switch includes a force-sensing resistor, and the analog switch is positioned below the digital switch with respect to the input button surface; and/or the digital switch is a first digital switch, a second digital switch is positioned below the first digital switch with respect to the input button surface, and the analog switch is coupled in series with the second digital switch.

Assignees

• Cattron North America Inc

Inventors

• Stagg David
• Hornung Thomas
• Wooten Ryan

Classifications

• H03K17/9647 Primary

  using a plurality of detectors, e.g. keyboard · CPC title

• H01H13/803 Primary

  characterised by the switching function thereof, e.g. normally closed contacts or consecutive operation of contacts · CPC title

• G06F3/016

  Input arrangements with force or tactile feedback as computer generated output to the user · CPC title

• G01L1/005

  by electrical means and not provided for in G01L1/06 - G01L1/22 · CPC title

• H01H13/785

  characterised by the material of the contacts, e.g. conductive polymers · CPC title