Ultrasonic Motion Sensor Modulation for Wireless Interference
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Solution Overview
Problem
Current ultrasonic motion sensors interfere with other wireless devices, such as electronic whiteboards and hearing aids, due to their use of ultrasound-based detection components, leading to operational disruptions.
Innovation Solution
A dual-technology motion sensor system that incorporates both ultrasonic and passive infrared (PIR) sensors, equipped with a control circuit and microprocessor, which modulates the ultrasonic radiation when interference is detected, allowing the PIR sensor to continue monitoring motion and controlling loads while minimizing interference with other ultrasound-based devices by adjusting thresholds and enabling/disabling the ultrasonic sensor element based on activity levels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If ultrasonic sensor element is used for motion detection, then motion detection capability is improved, but interference with other wireless devices occurs
Solution Approach 1:
The ultrasonic sensor element is dynamically controlled through modulation based on detected motion conditions. The sensor operates in different modes (continuous, pulsed, or disabled) depending on the motion detection state, allowing the system to adapt its ultrasonic emission behavior to prevent interference with other wireless devices while maintaining effective motion detection capability.
Solution Approach 2:
The system changes operational parameters of the ultrasonic sensor element by modulating its radiation output. Based on motion detection results, the system adjusts the ultrasonic emission characteristics (continuous vs. pulsed vs. disabled) to resolve interference issues while preserving motion detection functionality through the dual-technology approach combining ultrasonic and PIR sensors.
2Object-affected harmful factors
If ultrasonic radiation is modulated to reduce interference, then interference with other devices is reduced, but motion detection sensitivity may be affected
Solution Approach 1:
The system merges the capabilities of two different sensor technologies - ultrasonic sensors for detecting small objects and PIR sensors for detecting body heat and motion. This combination allows the system to maintain motion detection sensitivity across different scenarios while modulating ultrasonic radiation to reduce interference, as the PIR sensor provides complementary detection capability.
Solution Approach 2:
The control circuit acts as an intermediary that coordinates between the ultrasonic and PIR sensors, the microprocessor, and the load control system. It processes signals from both sensors, determines appropriate modulation levels for the ultrasonic radiation based on detected conditions, and maintains overall system operation to preserve motion detection sensitivity while reducing interference.
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
Effectively reduces interference between motion sensors and ultrasound-based devices by modulating ultrasonic radiation, ensuring continuous operation of both motion detection and load control systems without disrupting other wireless devices.
Implementation Method 1
Ultrasonic sensors typically use a transducer, which generates sound waves in the ultrasonic range, above 20,000 hertz (20 kilohertz or 20 KHz), by turning electrical energy into sound
Implementation Method 2
evaluates attributes of a target by interpreting the echoes from radio or sound waves
Implementation Method 3
a passive infrared (PIR) sensor is an electronic device that measures infrared (IR) light radiating from objects in its field of view
Implementation Method 4
At the core of a PIR sensor is a solid-state sensor or set of sensors, made from an approximately 1⁄4 inch-square of natural or artificial pyroelectric materials
Data Source
AI summary
A dual-technology motion sensor with an ultrasonic sensor element (transducer) and a PIR sensor element is disclosed. The dual-technology motion sensor is configured to modulate ultrasonic radiation emitted from the ultrasonic sensor element when the motion sensor detects a condition under which other wireless devices, especially ultrasound-based wireless devices, are in operation, thereby eliminating problems associated with interference.