RFID Reader Coil Voltage Variation for Vehicle Door Locking
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Solution Overview
Problem
Existing methods for triggering access door locking mechanisms in vehicles, such as those using hands-free access devices and RFID readers, incur high production costs and significant power consumption due to the need for proximity sensors and continuous electromagnetic signal transmission.
Innovation Solution
A method utilizing an RFID reader with a transmitting antenna and a coil to measure voltage variations, triggering the locking/unlocking procedure only when significant changes are detected, thereby reducing power consumption and production costs, and potentially replacing proximity sensors with the RFID reader.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If proximity sensors are installed to trigger the actuation procedure, then the triggering function is achieved, but the production cost increases
Solution Approach 1:
The RFID reader is made to perform multiple functions: both triggering the actuation procedure and identifying the transponder. By adding a coil to the RFID reader, it gains the ability to detect voltage variations that indicate a user's presence, thereby replacing the need for separate proximity sensors and reducing production costs.
2Reliability
If the RFID reader continuously transmits electromagnetic signals to activate transponders, then the identification function is maintained, but the power consumption increases
Solution Approach 1:
Instead of continuously transmitting electromagnetic signals, the RFID reader transmits signals periodically or on-demand. The reader first uses the coil to detect voltage variations indicating user presence, then activates the electromagnetic signal transmission only when needed, significantly reducing power consumption while maintaining identification functionality.
3Use of energy by moving object
If the RFID reader operates in low power mode, then the power consumption is reduced, but the triggering sensitivity may decrease
Solution Approach 1:
The coil acts as an intermediary sensing element that operates in low power mode to detect voltage variations. When a user approaches, the coil's voltage changes, triggering the RFID reader to activate its full electromagnetic signal transmission capability. This two-stage approach maintains triggering sensitivity while minimizing power consumption during idle periods.
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 approach significantly reduces power consumption to a few tens of microamperes and lowers production costs, enabling efficient and cost-effective triggering of access door locking mechanisms while maintaining reliability and minimizing interference from external electromagnetic sources.
Implementation Method 1
controlling the successive transmission, by the RFID reader, of electromagnetic pulses
Implementation Method 2
measuring, upon each pulse, a value representative of the electrical voltage at the terminals of the coil
Data Source
AI summary
A method and device for triggering, via an RFID reader (5) endowed with a transmitting antenna (6), a procedure for actuating an element for locking/unlocking the access doors (2) of a motor vehicle (1). A coil (7) is arranged in the vicinity and in the field of action of the transmitting antenna (6), and:the RFID reader (5) is commanded so as to control the successive transmission of electromagnetic pulses of the same power,upon each pulse, a value representative of the electrical voltage at the terminals of the coil (7) is measured,and the procedure for actuating the locking/unlocking element is triggered in the event of a variation in the measured values greater than a determined value.