Low-Power Vehicle Detection via Proximity-Triggered Directional Sensor
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Solution Overview
Problem
Existing vehicle detection systems in solar and/or battery-powered parking meters face challenges with accuracy and power consumption, with magnetometers requiring labor-intensive installation, ultrasonic and infrared systems being prone to interference, and more accurate systems like cameras and radar consuming excessive power, leading to reliability and maintenance issues.
Innovation Solution
A parking meter design that employs a low-power proximity sensor to trigger a directional sensor, allowing for accurate detection of vehicle presence and direction while minimizing continuous power usage by activating the directional sensor only when necessary.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a magnetometer is embedded in the parking space surface, then detection accuracy is improved, but installation complexity and cost increase due to surface coring
Solution Approach 1:
The patent introduces a magnetic field concentrator as an intermediary component placed between the magnetometer and the vehicle. This concentrator guides and concentrates the magnetic field lines from the vehicle toward the magnetometer sensor, thereby improving detection accuracy without requiring the magnetometer to be embedded in the parking space surface. The concentrator can be placed on the vehicle or held by a pedestrian, eliminating the need for surface coring while maintaining high detection accuracy.
2Device complexity
If a magnetometer is placed in the parking meter, then installation complexity is reduced, but detection accuracy decreases due to lack of directional capability
Solution Approach 1:
The magnetic field concentrator serves as a mediator that provides directional capability to the omnidirectional magnetometer. By concentrating magnetic field lines from a specific direction (the parking space) toward the sensor, the concentrator enables the meter-mounted magnetometer to distinguish vehicles in the correct parking space from those in adjacent spaces or stopped in the street, thereby improving directional detection accuracy without requiring complex sensor orientation.
Solution Approach 2:
The patent adds a spatial dimension to the detection system by introducing the magnetic field concentrator that shapes and directs the magnetic field in three-dimensional space. This allows the system to achieve directional sensitivity not through orienting the sensor itself, but through modifying the magnetic field distribution in space around the sensor, effectively adding directional information to an omnidirectional sensor.
3Measurement precision
If high-power directional sensors are used continuously, then detection accuracy is improved, but power consumption increases beyond battery/solar capacity
Solution Approach 1:
The system implements periodic action by using the low-power magnetometer to periodically scan for vehicles, and only activating the high-power directional sensor (camera or radar) when a vehicle is detected in proximity. This intermittent operation of the high-power sensor dramatically reduces overall power consumption while maintaining high detection accuracy when needed, making the system compatible with battery and solar power sources.
4Use of energy by moving object
If low-power ultrasonic or infrared systems are used, then power consumption is reduced, but detection reliability decreases due to signal interference and narrow detection angles
Solution Approach 1:
The patent replaces the acoustic (ultrasonic) and optical (infrared) detection systems with a magnetic field-based detection system using magnetometers. Magnetic fields are not affected by weather conditions, pedestrian traffic, or other environmental interferences that plague ultrasonic and infrared systems. This substitution maintains low power consumption while significantly improving detection reliability and expanding the detection angle, as magnetometers can detect vehicles from any direction without narrow beam constraints.
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 provides a reliable, low-power vehicle detection system that enhances accuracy and reduces maintenance costs by using a low-power proximity sensor to activate a directional sensor only when needed, improving detection precision without excessive power consumption.
Implementation Method 1
One technique for detecting the presence of a vehicle is to use a magnetometer located in the parking space
Implementation Method 2
Other vehicle detection systems have employed ultrasonic or infrared systems internal to a parking meter. Such systems send out a known ultrasonic or infrared signal and evaluate vehicle presence based on partial reflection of the signal
Implementation Method 3
Other vehicle detection systems have employed ultrasonic or infrared systems internal to a parking meter. Such systems send out a known ultrasonic or infrared signal and evaluate vehicle presence based on partial reflection of the signal
Data Source
AI summary
A parking meter detects an object in proximity, based on a change in a proximity measurement at the meter, activates a directional sensor in response to detecting the object, receives sensor data at a meter processor from the directional sensor, wherein the received sensor data indicates a predetermined direction to the detected object relative to the meter. The parking meter determines a presence of the object, or lack thereof, in the predetermined direction based on the sensor data, and upon a positive determination of the presence of the object, stores an indication of the presence of the object along with a time of the positive determination.