Capacitive Button Calibration via Pressure Detection

Solution Overview

Problem

Capacitive touch buttons in systems that must detect pressure during start-up cannot be pre-calibrated, leading to potential product failure if calibration is not correctly established, and existing solutions are prone to corruption or failure during software upgrades.

Innovation Solution

A system that includes a barcode reader with a capacitive sensing peripheral or connected component, which uses a processor to detect changes in capacitance patterns to initiate a calibration process, allowing the button to be recalibrated when necessary, enabling correct detection of pressed and released states.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If calibration is performed at start-up, then the button can be pre-calibrated, but the system cannot detect button pressure during start-up

Engineering Contradiction:

Improvebutton pressure detection accuracyVSAvoidstart-up process simplicity

Core Design Contradiction:

Measurement precisionVSEase of operation

Solution Approach 1:

The system performs preliminary detection of button pressure during start-up before calibration occurs. By detecting the button state in advance and storing this information, the system enables calibration to proceed accurately without requiring the button to be in a known initial state, thus resolving the contradiction between needing pressure detection and being able to calibrate.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system uses feedback from button pressure detection during start-up to adjust the calibration process. By monitoring the button state and using this information to guide calibration, the system achieves both accurate pressure detection and proper calibration, eliminating the trade-off between these two requirements.

Inventive Principle:

Principle #23Feedback

2Stability of the object's composition

If stored parameters are used for calibration, then the button initializes consistently, but the parameters can become corrupted making the button fail

Engineering Contradiction:

Improvecalibration consistencyVSAvoidbutton operation reliability

Core Design Contradiction:

Stability of the object's compositionVSReliability

Solution Approach 1:

The system performs self-calibration by detecting button pressure during start-up and using this information to establish calibration parameters automatically. This eliminates dependency on externally stored parameters that could be corrupted, while maintaining consistent calibration results, thus improving both reliability and stability.

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The system replaces the traditional method of using stored calibration parameters with a direct measurement approach. Instead of relying on pre-stored values that could be corrupted, the system performs real-time detection and calculation, substituting a more reliable electronic measurement process for a potentially fragile data storage approach.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Ease of operation

If calibration is not performed at start-up, then the system can detect button pressure, but the button cannot be pre-calibrated and may fail

Engineering Contradiction:

Improvestart-up flexibilityVSAvoidbutton function reliability

Core Design Contradiction:

Ease of operationVSReliability

Solution Approach 1:

The system performs preliminary detection of button pressure during start-up before calibration occurs. By detecting the button state in advance and storing this information, the system enables calibration to proceed accurately without requiring the button to be in a known initial state, thus resolving the contradiction between needing pressure detection and being able to calibrate.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system uses feedback from button pressure detection during start-up to adjust the calibration process. By monitoring the button state and using this information to guide calibration, the system achieves both accurate pressure detection and proper calibration, eliminating the trade-off between these two requirements.

Inventive Principle:

Principle #23Feedback

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

Enables capacitive button recalibration on demand, ensuring correct operation and allowing for software upgrades by restoring the relationship between input values and thresholds, thus preventing product failure and ensuring reliable functionality.

Implementation Method 1

The capacitive button is composed of analog and digital circuits, wires, and pads that are impacted by temperature variations. For this reason, a calibration is usually performed during start-up of a system or product so that the circuit only has to recognize a relative capacitance variation between 'pressed' and 'not pressed'

Methodology Applied

Scientific EffectCapacitance: Capacitance

Data Source

PatentUS11507226B1Recovery strategies for capacitive button calibration

Publication Date: 2022.11.22 DATALOGIC IP TECH

AI summary

A calibration process is started by a capacitive input variation when a capacitive button is pressed on a barcode reader. Or, the calibration process is started by the barcode reader scanning a configuration label or special label or barcode after the capacitive button on the barcode reader is inoperative. The calibration process realigns the input and the threshold to correctly configure the capacitive button.