Ultrasonic Access Control for Precise Reader Location Detection

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Solution Overview

Problem

Existing access control systems using Bluetooth technology face challenges with high power consumption, reduced credential detection range, and inaccurate position detection of mobile devices, leading to security issues and inefficient door access control.

Innovation Solution

An access control system utilizing ultrasonic technology in conjunction with Bluetooth to transmit unique identifiers and proximity signals, enabling precise location detection and secure door access by distinguishing between multiple locks and identifying user intent.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If Bluetooth technology is used for credential communication, then wireless communication capability is provided, but power consumption increases and credential detection range is reduced

Engineering Contradiction:
Improvepower consumptionVSAvoidcredential detection capability
Core Design Contradiction:
Use of energy by moving objectVSReliability

Solution Approach 1:

The patent introduces ultrasonic waves as an intermediary communication medium between the access control device and mobile device. The ultrasonic transmitter emits ultrasonic waves that carry credential data, which are then received by the mobile device's microphone. This intermediary ultrasonic communication method reduces the power consumption compared to continuous Bluetooth transmission while extending the effective detection range through acoustic wave propagation.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Measurement precision

If Bluetooth credential detection is used, then wireless access control is enabled, but position detection accuracy deteriorates and false credential detection increases

Engineering Contradiction:
Improveposition detection accuracyVSAvoidcredential detection accuracy
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The patent uses ultrasonic frequency modulation as an analog of 'color changes' to encode different credential information. Different ultrasonic frequencies or frequency patterns represent different credentials or credential types, enabling the system to distinguish between multiple credentials and accurately identify the intended one, thereby improving both position detection accuracy and reducing false detections.

Inventive Principle:
Principle #32Color changes

3Area of stationary object

If multiple credential readers are deployed in a facility, then coverage area increases, but credential identification accuracy decreases

Engineering Contradiction:
Improvecoverage areaVSAvoidcredential identification accuracy
Core Design Contradiction:
Area of stationary objectVSMeasurement precision

Solution Approach 1:

The patent segments the credential identification process by using unique ultrasonic frequency signatures for each access control device. Each reader/lock combination transmits or responds with a specific frequency pattern, allowing the mobile device to identify which specific reader it is communicating with even when multiple readers are present. This segmentation of identification through frequency coding maintains high accuracy across wide coverage areas.

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

The ultrasonic solution enhances precision in door access control by accurately identifying the location of the reader/lock, enhancing security and efficiency in securing door access control systems, enhancing user intent detection and reducing false positives.

Implementation Method 1

a first signal in a first protocol over ultrasound from the reader device to the mobile device

Methodology Applied
Scientific EffectUltrasonic transmission: Ultrasound

Data Source

PatentEP3533036B1Access control system and method using ultrasonic technology
Publication Date: 2025.12.10 SCHLAGE LOCK CO LLC
  • EP3533036B1 patent drawingFigure 1
  • EP3533036B1 patent drawingFigure 2
  • EP3533036B1 patent drawingFigure 3

AI summary

A system including a reader device and a mobile device having a user credential. The reader device includes an ultrasonic transmitter configured to transmit an identifier, and a wireless transceiver configured to receive information from and transmit information to the mobile device. The identifier is configured to be received by a microphone of the mobile device. The mobile device may determine a position of the mobile device based on the identifier.