Acceleration Sensor Error Sensing for Low-Power Vehicle Keys

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Solution Overview

Problem

Existing electronic vehicle keys with acceleration sensing devices face challenges in reducing energy consumption while maintaining reliability and preventing false triggers due to noise or surges, which can lead to increased power consumption and potential car theft.

Innovation Solution

A triaxial acceleration sensor with a capacitive MEMS technology, combined with a storage device using flip-flops and an error sensing mechanism, allows intermittent operation and error detection, ensuring accurate interrupt signals and reduced power consumption.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the acceleration sensing device operates continuously to ensure reliable detection, then the reliability is improved, but the energy consumption increases

Engineering Contradiction:

Improvedetection reliabilityVSAvoidenergy consumption

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

The acceleration sensing device operates intermittently rather than continuously. The microcomputer controls the sensing device to perform detection at specific intervals or under specific conditions, reducing overall energy consumption while maintaining adequate detection coverage for security purposes

Inventive Principle:

Principle #19Periodic action

2Reliability

If noise filtering is enhanced to prevent false triggers, then the reliability is improved, but the device complexity increases

Engineering Contradiction:

Improvefalse trigger preventionVSAvoidnoise filtering complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The system uses feedback mechanisms where the microcomputer monitors acceleration detection results and adjusts sensing operations accordingly. When no motion is detected for a predetermined period, the system reduces or stops sensing operations, preventing false triggers while maintaining a relatively simple device architecture

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The system performs preliminary assessment of acceleration patterns to determine whether further detection is necessary. By evaluating initial sensing results and comparing them against predefined thresholds or patterns, the system can prevent false triggers before they occur without requiring complex real-time filtering mechanisms

Inventive Principle:

Principle #10Preliminary action

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

The solution enhances the reliability of electronic vehicle keys by minimizing power usage and preventing false interrupts, thus improving security without increasing energy consumption.

Implementation Method 1

A triaxial acceleration sensor with a capacitive MEMS technology

Methodology Applied

Scientific EffectCapacitance: Capacitance

Implementation Method 2

A triaxial acceleration sensor with a capacitive MEMS technology

Methodology Applied

Scientific EffectMicroelectromechanical Systems: Microelectromechanical Systems

Data Source

PatentUS20250298052A1Storage device, sensing device, and sensor system

Publication Date: 2025.09.25 ROHM CO LTD

AI summary

A storage device includes a first and a second storage portion configured to store data with opposite polarities, and an error sensing portion configured to sense an error if the outputs of the first and second storage portions have the same polarity.