Radio Identification Locks with Segmented PIR Approach Detection
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Solution Overview
Problem
PIR sensors in electronic locks installed in frequently used areas like corridors in hotels, hospitals, and offices have high sensitivity, leading to unnecessary battery consumption and short service life due to detecting people passing by without operating the lock.
Innovation Solution
The PIR sensor is redesigned with horizontally adjacent sensor elements separated by a vertical web, reducing sensitivity and detection range, ensuring sufficient sensitivity only for approaching individuals, using a cover that is partially transparent to infrared wavelengths and incorporating a frame body with a conical taper to adjust detection angles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of stationary object
If the PIR sensor has high sensitivity to detect people from a distance, then the detection range is extended, but the battery energy consumption increases and service life decreases due to unnecessary activations when people pass by without operating the lock
Solution Approach 1:
The PIR sensor is divided into multiple sensor elements (first and second sensor elements) arranged adjacent to each other, with each element responsible for detecting thermal radiation from different directions. This segmentation allows the system to distinguish between people passing by and people approaching the lock, reducing false activations and energy consumption while maintaining adequate detection range
Solution Approach 2:
Each sensor element is assigned a specific detection zone with different sensitivity characteristics. The first sensor element detects thermal radiation primarily from one direction while the second sensor element detects from another direction. By assigning different local detection qualities to different sensor elements, the system can selectively activate only when a person is approaching (detected by both elements) rather than passing by (detected by only one element), thus reducing unnecessary energy consumption
2Use of energy by moving object
If the PIR sensor sensitivity is reduced to decrease energy consumption, then false activations are reduced, but the detection range becomes too short to activate the radio identification receiver in time before reaching the device
Solution Approach 1:
The PIR sensor is configured to detect thermal radiation from a distance using multiple sensor elements that can sense heat signatures of approaching people before they reach the lock. This preliminary detection allows the radio identification receiver to be activated in advance, providing sufficient time for the identification process to complete before the user reaches the device, thus avoiding time delays while maintaining energy efficiency through selective activation
3Measurement precision
If the PIR sensor detects people passing by in heavily frequented corridors, then the detection sensitivity is sufficient, but the service life of the power supply becomes too short due to continuous activations
Solution Approach 1:
The system uses feedback from multiple sensor elements to determine whether to activate the radio identification receiver. The control unit analyzes the detection signals from both sensor elements and only activates the receiver when the pattern indicates a person is approaching (both elements detect thermal radiation) rather than passing by (only one element detects). This feedback mechanism maintains high detection sensitivity for approaching users while filtering out false positives from passing pedestrians, thereby extending power supply service life in heavily frequented areas
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 configuration reduces energy consumption by activating the radio identification receiver only when an individual is near, ensuring timely identification and lock operation without delay.
Implementation Method 1
PIR sensors are pyroelectric sensors or passive infrared sensors that have sensor elements made of pyroelectric material in the form of a thin polarized crystal. Thermal radiation in the infrared wavelength range incident onto the pyroelectric material is absorbed. The resulting temperature difference affects the polarization of the crystal and causes a change of the electrical potential that can be measured with an amplifier.
Implementation Method 2
Thermal radiation in the infrared wavelength range incident onto the pyroelectric material is absorbed.
Data Source
AI summary
The invention relates to a radio identification device including a radio identification receiver and a proximity detector connected to the radio identification receiver, wherein the proximity detector includes a pyroelectric PIR sensor for detecting an approach of a person located in the vicinity of the radio identification receiver and is configured to activate the radio identification receiver when a person approaching the proximity detector is detected. The PIR sensor includes two sensor elements arranged horizontally adjacent to each other having a sensor surface sensitive to infrared waves covered by a cover that is at least partially transparent for infrared wavelengths, wherein a vertical web is arranged between the pair of sensor elements in the gap between the cover and a platform of the PIR sensor carrying the sensor elements.