NFC Lock Powering via Mobile Phone Induction
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Solution Overview
Problem
Locks powered by NFC technology face issues when the internal battery discharges, preventing communication and mechanical operation, necessitating an external power source or battery replacement, which can be inconvenient.
Innovation Solution
The mobile phone is used as a remote power source by switching to 'reader mode' to transmit energy to the lock via NFC, allowing temporary charging of a buffer capacitor for authorization and unlocking, eliminating the need for an external battery or electrical connector.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the lock uses an internal battery for power supply, then the lock can operate autonomously, but the lock becomes inoperative when the battery is discharged or fails
Solution Approach 1:
The patent introduces a buffer capacitor as an intermediary energy storage element between the NFC antenna and the lock circuits. When energy is received via NFC, it is stored in the capacitor and can be used to power the lock temporarily, enabling operation even when the internal battery is discharged. This mediator allows energy transfer without direct battery dependence.
Solution Approach 2:
The lock system performs self-service by using the mobile phone's NFC field to recharge its buffer capacitor when the internal battery is depleted. The system automatically detects low battery conditions and accepts energy transfer from the phone's NFC field without requiring external intervention or battery replacement.
2Reliability
If an emergency power supply point with external battery is provided, then the lock can be powered during internal battery failure, but the device complexity increases and requires electrical connectors
Solution Approach 1:
The patent replaces the mechanical/electrical connection system (external battery with electrical connectors) with a wireless electromagnetic field-based power transfer system using NFC technology. The mobile phone's NFC antenna generates an electromagnetic field that induces current in the lock's NFC antenna, eliminating the need for physical connectors and external battery hardware.
Solution Approach 2:
The NFC antenna in the lock serves multiple functions: it acts as both a communication interface for normal operation and as a power reception antenna when the internal battery fails. This multi-functionality eliminates the need for separate emergency power supply hardware, reducing device complexity while maintaining reliability.
3Reliability
If the lock requires battery replacement or external power connection, then power can be restored, but the loss of time increases due to intervention required
Solution Approach 1:
The lock system performs preliminary action by automatically detecting when the internal battery is discharged and immediately entering a state where it can receive energy via NFC. The buffer capacitor is pre-charged during normal operation and automatically activates when needed, eliminating the time required for user intervention or battery replacement procedures.
4Reliability
If the lock operates in reader mode continuously, then communication with the phone is maintained, but the energy consumption increases
Solution Approach 1:
The lock uses periodic action by activating the buffer capacitor charging only when needed (when internal battery is discharged) rather than continuously. The system alternates between normal battery-powered operation and NFC-based emergency power reception, reducing overall energy consumption while maintaining communication reliability when required.
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
Enables secure and convenient remote powering of the lock without an external battery, ensuring continued operation during internal battery failure by using the phone's energy to charge the lock's circuits, facilitating door opening.
Implementation Method 1
The lock comprises an induction coil forming an antenna, excited by an alternating signal so as to produce in the surrounding space a variable magnetic field... The principle of the invention consists in using the mobile telephone as a power source for remotely powering the lock, that is to say transmitting energy to it by non-galvanic means via the NFC circuits.
Data Source
Figure 1~2
AI summary
The invention relates to a system comprising: a lock (10) provided with electronic circuits for transmission/reception via NFC and electric circuits for controlling mechanical locking/unlocking members, and a mobile phone (16) provided with circuits allowing same to operate in NFC mode. In addition, means are provided for transmitting power to the lock by means of remote power feeding (18) from the phone, such as to charge a buffer capacitor in order subsequently to provide power temporarily to the electronic and electric circuits of the lock while the lock is querying the NFC circuits of the phone in order to check the authorisation of the person with the phone and to order to opening of the door.