Button press detection system
Disclosed herein are systems and methods for accurately detecting button presses and/or button releases on a keypad of a camera such as an endoscopic camera head. A button press and/or a button release may be detected by determining a change in the sensor voltage output from a magnetic field sensor and identifying a spike in the sensor voltage change. A spike occurs when the slope of the sensor voltage has a magnitude that is greater than a slope threshold, and indicates a button press and/or a button release. Aspects of the disclosure comprise a controller that identifies a spike. The controller may identify a second spike and determine the type of button press based on the duration between the first spike and the second spike. The disclosed systems and methods may further include and apply to a keypad comprising a plurality of buttons, such as closely-spaced buttons and concentric buttons.
1 . A method of detecting a button press and/or a button release of a button on a camera head, the method comprising:
receiving a sensor voltage from a magnetic field sensor;
determining a change of the sensor voltage over time; and
identifying a spike comprising a slope of the sensor voltage having a magnitude greater than a slope threshold, wherein the spike indicates the button press and/or the button release.
2 . The method of claim 1 , further comprising:
registering the button press when the slope of the sensor voltage has a first orientation, and the spike is identified or the button is in a final position; or
registering the button release when the slope of the sensor voltage has a second orientation, and the spike is identified or the button is in an initial position.
3 . The method of claim 1 , wherein the spike occurs when:
the button is between an intermediate position and a final position;
a magnet associated with the button has a high velocity; or
a dome associated with the button has a low level of resistance, wherein the dome comprises the low level of resistance and a high level of resistance.
4 . The method of claim 1 , further comprising:
identifying a low slope of the sensor voltage comprising a non-zero magnitude less than the slope threshold, wherein the low slope:
does not indicate the button press and/or the button release;
occurs when a dome associated with the button has a high level of resistance, wherein the dome comprises a low level of resistance and the high level of resistance;
occurs when a magnet associated with the button has a low velocity; or
when the button is between an initial position and an intermediate position.
5 . The method of claim 1 , further comprising:
determining a position of the button based on the slope of the sensor voltage, wherein the position of the button comprises an initial position, an intermediate position, and a final position.
6 . The method of claim 1 , further comprising:
identifying a second spike in the sensor voltage change, wherein the second spike comprises the slope of the sensor voltage having a magnitude greater than the slope threshold and a second orientation; and
registering the button press as:
a short press when a duration between the spike and the second spike is shorter than a short press duration threshold;
a long press when a duration between the spike and the second spike is longer than the short press duration threshold and shorter than a long press duration threshold; or
a press-and-hold press when a duration between the spike and the second spike is longer than the long press duration threshold.
7 . The method of claim 1 , wherein the camera head comprises a first button and a second button, the method further comprising:
determining whether the button press corresponds to the first button or the second button based on the slope of the sensor voltage or an orientation of the slope of the sensor voltage.
8 . A system comprising a camera head, the system comprising:
a button;
a magnet;
a magnetic field sensor that outputs a sensor voltage indicative of magnetic flux between the magnet and the magnetic field sensor; and
a controller configured to:
determine a change of the sensor voltage over time; and
identify a spike in the sensor voltage change, wherein the spike comprises a slope of the sensor voltage having a magnitude greater than a slope threshold, wherein the spike indicates a button press and/or a button release.
9 . The system of claim 8 , wherein the controller is configured to:
register the button press when the slope of the sensor voltage has a first orientation, and the spike is identified or the button is in a final position; or
register the button release when the slope of the sensor voltage has a second orientation, and the spike is identified or the button is in an initial position.
10 . The system of claim 8 , wherein the spike occurs when:
the button is between an intermediate position and a final position; or
the magnet has a high velocity.
11 . The system of claim 8 , further comprising:
a dome located between the magnet and the magnetic field sensor, the dome comprising a low level of resistance and a high level of resistance, wherein the spike occurs when the dome has the low level of resistance.
12 . The system of claim 8 , further comprising:
a dome located between the magnet and the magnetic field sensor, the dome comprising a low level of resistance and a high level of resistance;
wherein the controller is configured to:
identify a low slope of the sensor voltage comprising a non-zero magnitude less than the slope threshold, wherein the low slope occurs when:
the dome has the high level of resistance;
the magnet has a low velocity; or
the button is between an initial position and an intermediate position.
13 . The system of claim 8 , wherein the button comprises a plurality of positions determined based on the slope of the sensor voltage, where the plurality of positions comprises an initial position, an intermediate position, and a final position.
14 . The system of claim 8 , wherein the controller is configured to:
identify a second spike in the sensor voltage change, wherein the second spike comprises the slope of the sensor voltage having a magnitude greater than the slope threshold and a second orientation; and
register the button press:
when a duration between the spike and the second spike is less than a duration threshold corresponding to a type of button press;
as a short press when a duration between the spike and the second spike is shorter than a short press duration threshold;
as a long press when a duration between the spike and the second spike is longer than the short press duration threshold and shorter than a long press duration threshold; or
as a press-and-hold press when a duration between the spike and the second spike is longer than the long press duration threshold.
15 . The system of claim 8 , wherein the camera head comprises a first button and a second button, wherein the controller is configured to:
determine whether the button press and/or the button release corresponds to the first button or the second button based on the slope of the sensor voltage.
16 . The system of claim 8 , wherein the camera head comprises one or more buttons and one or more magnetic field sensors, wherein a number of the one or more buttons is the same as a number of the one or more magnetic field sensors.
17 . The system of claim 8 , wherein the camera head comprises a plurality of buttons and one or more magnetic field sensors, wherein a number of the plurality of buttons is greater than a number of the one or more magnetic field sensors.
18 . An apparatus comprising:
a button;
a magnet;
a magnetic field sensor that outputs a sensor voltage indicative of magnetic flux between the magnet and the magnetic field sensor; and
a non-transitory computer-readable medium encoding instructions which, when executed by a processor, cause the processor to:
determine a change of the sensor voltage over time; and
identify a spike in the sensor voltage change, wherein the spike comprises a slope of the sensor voltage having a magnitude greater than a slope threshold, wherein the spike indicates a button press and/or a button release.
19 . The apparatus of claim 18 , wherein the non-transitory computer-readable medium cause the processor to:
register the button press when the slope of the sensor voltage has a first orientation, and the spike is identified or the button is in a final position; or
register the button release when the slope of the sensor voltage has a second orientation, and the spike is identified or the button is in an initial position.
20 . The apparatus of claim 18 , wherein the non-transitory computer-readable medium cause the processor to:
identify a second spike in the sensor voltage change, wherein the second spike comprises the slope of the sensor voltage having a magnitude greater than the slope threshold and a second orientation; and
register the button press:
when a duration between the spike and the second spike is less than a duration threshold corresponding to a type of button press;
as a short press when a duration between the spike and the second spike is shorter than a short press duration threshold;
as a long press when a duration between the spike and the second spike is longer than the short press duration threshold and shorter than a long press duration threshold; or
as a press-and-hold press when a duration between the spike and the second spike is longer than the long press duration threshold.