Passive NFC Entry Device Energy Harvesting
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Solution Overview
Problem
Existing remote keyless entry (RKE) systems for secured enclosures rely on battery-powered devices, which are prone to charge depletion and require frequent maintenance, and lack efficient methods for energy harvesting from nearby NFC-enabled devices.
Innovation Solution
A passive NFC entry device that harvests energy from proximate NFC-enabled smartphones or mobile devices using electromagnetic induction, eliminating the need for a cellular battery and enabling communication with the RKE control unit to activate door actuators or other access mechanisms.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a battery-powered device is used for remote keyless entry, then the device can operate independently and provide continuous access control, but the device requires frequent maintenance due to charge depletion and has limited operational duration
Solution Approach 1:
The entry device harvests energy from the NFC-enabled mobile device itself during the NFC communication process, allowing the passive device to power its RF transceiver without an external battery. This self-service approach eliminates battery replacement maintenance while enabling continuous operation.
Solution Approach 2:
The patent introduces an energy harvesting circuit as an intermediary that captures electromagnetic energy from the NFC mobile device's magnetic field and converts it to electrical energy to power the RF transceiver, bridging the energy gap between the active mobile device and the passive entry device.
2Reliability
If a battery is integrated into the entry device, then the device can maintain continuous operation and provide reliable access control, but the device complexity increases and requires periodic maintenance
Solution Approach 1:
The patent extracts the battery component from the entry device architecture, transforming it from an active battery-powered device to a passive energy-harvesting device. This removal simplifies the device structure by eliminating battery compartments, charging circuits, and associated maintenance requirements.
Solution Approach 2:
The entry device obtains its operating energy from the NFC mobile device during normal communication operations, eliminating the need for integrated power storage components and reducing overall device complexity while maintaining operational reliability.
3Ease of operation
If energy is harvested from NFC signals, then the device can operate without a battery and reduce maintenance requirements, but the available energy from NFC signals is limited and must be efficiently utilized
Solution Approach 1:
The patent employs partial action by using the NFC mobile device's magnetic field not only for data communication but also for energy harvesting. The energy harvesting circuit captures a portion of the electromagnetic energy during normal NFC operations, sufficient to power the RF transceiver for access control without requiring excessive energy input.
Solution Approach 2:
The patent changes the energy parameter by converting electromagnetic energy from the NFC magnetic field into electrical energy through electromagnetic induction, and further transforms it into a suitable voltage level for powering the RF transceiver component, making efficient use of the limited available energy.
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 NFC entry device provides reliable and maintenance-free RKE access by leveraging the energy from NFC signals to power the RF transceiver, ensuring secure and efficient operation without battery depletion issues.
Implementation Method 1
harvests energy from proximate NFC-enabled smartphones or other mobile devices using electromagnetic induction
Data Source
AI summary
A near-field communication (NFC) entry device is provided for remote keyless entry (RKE) into an enclosure having an RKE control unit, a door, and a door actuator. The NFC entry device includes a housing and a printed circuit board assembly (PCBA). The housing mounts to the enclosure. The PCBA is enclosed within a cavity of the housing, and includes first and second surfaces, an RF antenna and an inductor coil connected to the first surface, and an NFC communication chipset connected to the second surface. The NFC entry device is characterized by an absence of a cellular battery, and passively harvests energy from a smartphone or other battery powered mobile device via the inductor coil. The passively harvested energy is used to communicate a control signal to the RKE control unit, via the RF antenna, which activates the door actuator.