RF Energy-Harvesting Electronic Lock for Battery-Free Authorization

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Solution Overview

Problem

Current NFC-enabled electronic locks require a constant NFC reader, leading to battery drain and inflexible programming, as they need to be programmed by a system operator and cannot be changed remotely.

Innovation Solution

An electronic lock that harvests energy from an RF connection with a mobile device to process authorization tokens and control unlocking, using a secondary antenna for energy storage and secure communication, enabling secure and flexible authorization without battery power.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If an NFC reader is constantly active in the electronic lock, then authorization processing is always available, but battery power is quickly depleted

Engineering Contradiction:
Improveauthorization availabilityVSAvoidbattery power consumption
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The NFC reader in the electronic lock operates periodically rather than continuously. The reader activates only when needed for authorization processing and remains inactive otherwise, dramatically reducing power consumption while maintaining authorization availability when required.

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The mobile device serves itself by acting as an active NFC initiator that can wake up or activate the lock's NFC reader through its own RF field. This eliminates the need for the lock's reader to constantly poll for access devices, as the mobile device can trigger the reader activation on-demand.

Inventive Principle:
Principle #25Self-service

2Ease of operation

If a smart card is used as key replacement, then contactless access is enabled, but the card must be programmed via NFC interface by a system operator and cannot be changed remotely

Engineering Contradiction:
Improvecontactless accessVSAvoidremote programming capability
Core Design Contradiction:
Ease of operationVSAdaptability or versatility

Solution Approach 1:

The roles are inverted: instead of the lock programming the smart card, the mobile device (acting as a programmable key) receives authorization data from a remote server and stores it locally. This allows remote programming and policy changes to be pushed to the mobile device without requiring physical access to the lock or card programming capabilities at the lock.

Inventive Principle:
Principle #13The other way round (Inversion)

Solution Approach 2:

A remote server acts as an intermediary between the authorization policy source and the mobile device. The server can remotely update authorization tokens and policies, which are then transmitted to the mobile device over a network connection, enabling flexible remote reconfiguration without system operator intervention at the lock.

Inventive Principle:
Principle #24Intermediary (Mediator)

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

Significantly reduces power consumption and allows for remote authorization policy changes, enhancing security and flexibility by using harvested energy for unlocking and communication.

Implementation Method 1

an electronic lock, being adapted to harvest energy from a radio frequency (RF) connection established between a mobile device and said electronic lock

Methodology Applied
Scientific EffectElectromagnetic energy harvesting: Electromagnetic Induction

Data Source

PatentEP2804153B1Electronic lock, locking system and method of operating an electronic lock
Publication Date: 2018.11.21 NXP BV
  • EP2804153B1 patent drawingFigure 1
  • EP2804153B1 patent drawingFigure 2
  • EP2804153B1 patent drawingFigure 3

AI summary

According to an aspect of the invention, an electronic lock is conceived, being adapted to harvest energy from a radio frequency (RF) connection established between a mobile device and said electronic lock, further being adapted to use the harvested energy for processing an authorization token received via said RF connection from the mobile device, and further being adapted to use the harvested energy for controlling an unlocking switch in dependence on a result of said processing.