Switch Actuation Detection Using Preliminary Contact State Query

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Solution Overview

Problem

Conventional mechanical switches experience delayed response due to bouncing behavior, leading to inefficiencies in detecting and reporting contact state changes, particularly in applications requiring quick actuation, such as keyboards and automotive controls.

Innovation Solution

A processor unit performs a second query immediately after detecting a contact state change, ensuring it precedes any expected bounce and excluding electrostatic discharge errors, while prioritizing the output signal to minimize reporting delay.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a conventional debounce waiting period is implemented after detecting a contact state change, then false detections from bouncing are eliminated, but the response time and reporting speed of the switch actuation are significantly delayed

Engineering Contradiction:

Improveaccuracy of contact state detectionVSAvoidresponse time of switch actuation

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The system performs a preliminary second query of the contact state immediately after the first detection of a change, before the debounce period would normally elapse. This preliminary check confirms the validity of the detected change without waiting for the full debounce time, thereby reducing response time while maintaining reliability by ensuring the change is real and not a bounce artifact

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The invention skips or rushes through the traditional debounce waiting period by performing the second query much sooner than conventional debounce times would dictate. This allows the system to quickly validate the contact state change and report it, achieving fast response times while still eliminating false detections through the rapid re-querying mechanism

Inventive Principle:

Principle #21Skipping (Rushing through)

2Reliability

If a second query is performed after the debounce time to confirm contact state change, then electrical interference such as electrostatic discharge is filtered out, but the reporting delay increases to tens of milliseconds

Engineering Contradiction:

Improveexclusion of electrostatic discharge errorsVSAvoiddelay between actuation and reporting

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The system performs the second confirming query as a preliminary action immediately after the first detection, well before the full debounce time would elapse. This allows electrostatic discharge errors to be filtered out through the rapid re-querying, while the overall delay is minimized because the system does not wait for the complete debounce period before reporting the change

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The invention implements periodic querying of the contact state at very short intervals immediately following the detected change. This periodic action occurs much faster than conventional debounce-based approaches, allowing the system to quickly confirm the validity of the change and report it with minimal delay while still excluding electrostatic discharge errors through the repeated sampling

Inventive Principle:

Principle #19Periodic action

3Speed

If the contact state is queried immediately upon actuation, then the response time is minimized, but false detections from bouncing and electrical interference cannot be excluded

Engineering Contradiction:

Improvespeed of contact state detectionVSAvoidaccuracy of contact state detection

Core Design Contradiction:

SpeedVSReliability

Solution Approach 1:

The system performs a preliminary second query immediately after the first detection to quickly validate the contact state change. This preliminary action occurs so rapidly that it maintains near-immediate response times while providing the necessary verification to exclude false detections from bouncing and electrical interference

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The invention implements a feedback mechanism where the result of the second query feeds back into the decision of whether to report the contact state change. This rapid feedback loop occurs immediately upon actuation, allowing the system to maintain high speed while ensuring reliability by only reporting changes that are confirmed by the second query to be genuine and not artifacts of bouncing or interference

Inventive Principle:

Principle #23Feedback

Data Source

PatentUS11442553B2Apparatus and method for detecting actuation of a switch

Publication Date: 2022.09.13 CHERRY GMBH

AI summary

The invention relates to a method and an apparatus with circuitry comprising at least one mechanical switch serving to open and/or close an electric contact and a processor unit serving to perform first query and a second query of a contact state of the contact, with the processor unit further serving to provide an output signal on the basis of information on a change of the contact state of the contact detected by means of the first and second queries, wherein the processor unit is configured to perform the second query after the first query with a timing so that the second query precedes an expected bounce of the contact.