Trackpad Input Error Mitigation via Pressure Change Filtering

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Solution Overview

Problem

Trackpads often experience cursor wobble due to unintentional finger movements, especially when a finger first touches the surface or when resting fingers are misinterpreted as gesturing or scrolling inputs, leading to unintended actions on the computing device screen.

Innovation Solution

A trackpad system that includes a sensor, controller, bus, kernel driver, and gesture library to detect and mitigate cursor wobble by ignoring predetermined pressure changes, temporarily discarding movements associated with increasing pressure, and updating records to allow or block pressure changes based on distance traveled and time since contact, thereby reducing unintended cursor movements.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If the trackpad detects and responds to all finger contacts and pressure changes, then the responsiveness and sensitivity of the trackpad is improved, but cursor wobble and misinterpretation of resting finger inputs occur

Engineering Contradiction:

Improvetrackpad input detection accuracyVSAvoidinput interpretation accuracy

Core Design Contradiction:

Measurement precisionVSReliability

Solution Approach 1:

The system performs preliminary analysis of pressure changes and contact patterns before interpreting them as valid inputs. By detecting predetermined pressure changes between consecutive contacts or during single contacts, and by monitoring pressure changes after predetermined periods without contact, the system proactively identifies and mitigates potential cursor wobble and resting finger misinterpretations before they cause unintended actions.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system continuously monitors trackpad contact data and provides feedback by comparing consecutive contacts and pressure changes. The gesture library receives feedback about pressure patterns and contact sequences, allowing it to distinguish between intentional gestures and unintentional movements, thereby resolving the contradiction between sensitivity and reliability.

Inventive Principle:

Principle #23Feedback

2Stability of the object's composition

If the trackpad ignores pressure changes to reduce cursor wobble, then cursor stability is improved, but legitimate input gestures may be missed

Engineering Contradiction:

Improvecursor stabilityVSAvoidinput recognition accuracy

Core Design Contradiction:

Stability of the object's compositionVSProductivity

Solution Approach 1:

The system applies partial filtering by ignoring only specific pressure changes that meet predetermined criteria (such as pressure changes between consecutive contacts or changes after predetermined periods without contact). This selective approach provides excessive filtering for problematic cases while preserving legitimate gestures, achieving cursor stability without sacrificing input recognition accuracy.

Inventive Principle:

Principle #16Partial or excessive action

Data Source

PatentUS8970525B1Method and system for trackpad input error mitigation

Publication Date: 2015.03.03 GOOGLE LLC

AI summary

In response to detecting a predetermined pressure change between two consecutive contacts on a trackpad of a computing device, the two consecutive contacts are ignored. In response to detecting a predetermined pressure change of a single contact on the trackpad, the single contact is ignored. After detecting a new contact on the trackpad after a predetermined period of time without any contact on the trackpad, any movement tied to a predetermined amount of increasing pressure on the trackpad for the new contact is temporarily discarded, for a preset amount of time.