Capacitive Humidity Sensor Layout for Secure Vehicle Authentication

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Solution Overview

Problem

Current systems for controlling vehicle access and user authentication based on moisture and pressure values lack precision and security, particularly in ensuring only authorized users can access vehicle systems safely and comfortably.

Innovation Solution

A capacitive moisture and pressure sensor system integrated into flexible carrier materials, such as woven fabrics, with electrodes and dielectric layers that measure capacitance changes due to moisture and pressure, communicating data to a central CPU for authentication and system control, including wireless communication and energy harvesting for power.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If moisture and pressure sensors are used for user authentication, then vehicle access control can be implemented, but the precision and security of authentication are insufficient

Engineering Contradiction:
Improveauthentication precisionVSAvoidauthentication security
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The patent combines multiple sensing functions (moisture detection, pressure detection, temperature detection) into an integrated sensor system. The moisture sensor and pressure sensor are merged into a single authentication system, allowing cross-validation of measurements. This combination enables more precise user identification by analyzing multiple physiological parameters simultaneously, thereby improving both authentication precision and security without requiring separate sensor systems.

Inventive Principle:
Principle #5Merging (Combining)

2Measurement precision

If capacitive sensors with dielectric layers are used, then moisture measurement capability is improved, but device complexity increases

Engineering Contradiction:
Improvemoisture measurement accuracyVSAvoidsensor structure complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent employs thin-film capacitive structures with flexible dielectric layers deposited directly onto substrate surfaces. The dielectric layer is implemented as a thin film rather than a bulky component, maintaining sensor flexibility and conformability while providing sufficient capacitance modulation for accurate moisture measurement. This thin-film approach reduces structural complexity compared to traditional discrete capacitor designs.

Inventive Principle:
Principle #30Flexible shells and thin films

Solution Approach 2:

The capacitive sensor structure serves multiple functions: it acts as both a moisture sensor and a pressure sensor, and can also function as a temperature sensor when combined with appropriate materials. This multi-functionality eliminates the need for separate sensor structures, reducing overall device complexity while maintaining high measurement precision through the universal capacitive measurement principle.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Adaptability or versatility

If processing units and CPU are separated, then system modularity is improved, but data communication overhead increases

Engineering Contradiction:
Improvesystem modularityVSAvoiddata communication time
Core Design Contradiction:
Adaptability or versatilityVSLoss of time

Solution Approach 1:

The system is divided into distinct functional modules: sensor modules for data acquisition, processing units for local signal conditioning and preliminary analysis, and a central CPU for high-level decision-making. This segmentation allows each module to be optimized independently and facilitates flexible system configuration. The processing units perform local preprocessing to minimize the amount of data that needs to be transmitted to the CPU, reducing communication overhead despite the modular architecture.

Inventive Principle:
Principle #1Segmentation

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

Provides accurate and secure user authentication by determining individual characteristics from moisture and pressure values, ensuring only authorized users access vehicle systems, enhancing safety and comfort while reducing power limitations through energy harvesting.

Implementation Method 1

the sensor comprises at least one capacitor with at least two electrodes which are arranged relative to one another... at least one dielectric layer is arranged between the electrodes... a capacitance is at least partially changed by the liquid at least partially impinging on the dielectric layer

Methodology Applied
Scientific EffectCapacitance: Capacitance

Implementation Method 2

A capacitive humidity sensor is essentially a capacitor whose dielectric preferably consists of a hygroscopic polymer layer that absorbs or releases moisture depending on the ambient air humidity

Methodology Applied
Scientific EffectAbsorption (physical): Absorption (physical)

Data Source

PatentEP3625087B1Control system for evaluating measured pressure and/or humidity values
Publication Date: 2024.03.06 B HORIZON GMBH
  • EP3625087B1 patent drawingFigure 1A
  • EP3625087B1 patent drawingFigure 1B
  • EP3625087B1 patent drawingFigure 1C

AI summary

The invention relates to a control system for measuring pressure and/or humidity, comprising at least one device for measuring pressure and/or humidity, at least one sensor for measuring pressure and/or humidity, wherein the sensor comprises at least one capacitor having at least two electrodes which, in particular, are arranged in a horizontal direction along one another and on a, in particular, flexible carrier material. At least one dielectric layer is arranged between the electrodes, wherein at least one, at least partially liquid-permeable and/or liquid-absorbing moisture layer is arranged at least in places on one side, which faces away from the carrier material, of at least electrode and/or the dielectric layer. The at least one electrode and/or the dielectric layer are thus arranged in a transverse direction between the carrier material and the moisture layer, so that a capacitance at least partially changes due to the liquid at least partially incident on the dielectric layer, wherein a processing unit is set up and provided to measure and/or store measured values of the sensor. Thus, a capacitive humidity sensor is created. The invention is characterized in that the data captured by the sensor is sent from the processing unit to a central CPU, wherein said data is processed by the processing unit.