Capacitive Sensor Transceiver Circuitry for Wearable Authentication

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Solution Overview

Problem

Existing communication technologies between devices lack efficient and secure methods for authentication and data transmission, particularly in scenarios requiring direct device-to-device communication without separate hardware modules, especially for wearable devices.

Innovation Solution

The use of capacitive coupling through a human body for device-to-device communication, where a wearable device with capacitive sensor transceiver circuitry transmits and receives signals for authentication and data exchange, utilizing existing touch panel circuitry in devices like smartphones and tablets, and implementing ad hoc communication protocols for secure transactions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If capacitive coupling through human body is used for device-to-device communication, then additional hardware modules are eliminated and power consumption is reduced, but communication security and authentication reliability may be compromised

Engineering Contradiction:
Improvehardware module complexityVSAvoidauthentication reliability
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The capacitive touch panel circuitry is designed to perform multiple functions: traditional touch screen operation and device-to-device communication. The same capacitive sensors and control circuitry used for user interaction are repurposed to detect and process communication signals, eliminating the need for separate communication hardware modules while maintaining full functionality

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

Solution Approach 2:

The human body serves as a capacitive intermediary or mediator between two devices. By coupling the capacitive touch panel to the user's body, the system enables signal transmission between devices without direct physical connection, using the body's capacitance as a coupling medium for authentication data exchange

Inventive Principle:
Principle #24Intermediary (Mediator)

2Use of energy by moving object

If capacitive coupling through human body is used for device-to-device communication, then power consumption is reduced, but communication range and signal strength may be limited

Engineering Contradiction:
Improvepower consumptionVSAvoidsignal transmission capability
Core Design Contradiction:
Use of energy by moving objectVSSpeed

Solution Approach 1:

The system uses partial action by leveraging only the necessary capacitive coupling through the user's body for authentication exchanges, rather than maintaining continuous high-power communication. The low-power capacitive mode is used specifically for authentication data transfer, while other communication needs can fall back to traditional higher-power methods

Inventive Principle:
Principle #16Partial or excessive action

Solution Approach 2:

The capacitive touch panel circuitry serves itself by performing both traditional touch screen functions and device-to-device communication functions. The existing high-voltage drive circuits and sensor array are repurposed to generate and detect communication signals, eliminating the need for separate low-power communication hardware

Inventive Principle:
Principle #25Self-service

3Adaptability or versatility

If ad hoc communication protocols are implemented for secure transactions, then communication flexibility and adaptability are improved, but protocol complexity and implementation difficulty increase

Engineering Contradiction:
Improvecommunication protocol flexibilityVSAvoidprotocol implementation complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The authentication protocol merges multiple functions into a unified capacitive communication process: device identification, authentication data exchange, and transaction confirmation are all handled through the same capacitive coupling interface, simplifying the overall protocol implementation while maintaining security

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The system performs preliminary authentication exchanges before establishing full communication. Authentication credentials are verified through capacitive coupling in advance, allowing the devices to establish a trusted connection before conducting broader transactions, which simplifies subsequent communication protocols

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

This method enables secure and efficient device-to-device communication without additional hardware, reducing power consumption and providing secure authentication and transaction processing, leveraging the human body as a communication channel for capacitive coupled signaling.

Implementation Method 1

capacitive coupled signal from a host device. The capacitive coupled signal is received through the body of the user of the wearable device

Methodology Applied
Scientific EffectCapacitive coupling: Capacitance

Data Source

PatentEP3075085B1Wearable communication devices for secured transaction and communication
Publication Date: 2020.01.08 SHENZHEN GOODIX TECH CO LTD
  • EP3075085B1 patent drawingFigure 1A~1B
  • EP3075085B1 patent drawingFigure 2A~2B
  • EP3075085B1 patent drawingFigure 3

AI summary

A wearable device for capacitive coupled communications is described. The wearable device includes capacitive sensor transceiver circuitry configured to receive a capacitive coupled signal from a host device. The capacitive coupled signal is received through a body of a user of the wearable device and is modulated to include a request for authentication data to authenticate the wearable device with the host device. The wearable device includes processing circuitry in communication with the capacitive sensor transceiver circuitry to process the received capacitive coupled signal and transmit authentication data modulated on a capacitive coupled reply signal to the host device. The capacitive coupled reply signal modulated with the authentication data is transmitted through the body of the user of the wearable device. The capacitive sensor transceiver circuitry receives another capacitive coupled signal from the host device modulated with information indicating a successful authentication of the wearable device with the host device.