Infrared Door Sensor Timing Control for Interference Reduction
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Solution Overview
Problem
Conventional infrared (IR) sensors used in automatic door systems face challenges such as interference from moving doors, limited coverage area, and susceptibility to noise, which affect their ability to accurately detect traffic and control door opening/closing sequences efficiently.
Innovation Solution
The proposed IR sensor system includes a controller that adjusts the timing of emitting and listening phases, determines the frequency and phase of interference beams, and designates primary or secondary sensor status to minimize interference, allowing for individual control of emitters and receptors to create customizable IR curtains for enhanced detection and reduced noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If multiple door sensors are deployed to increase detection coverage, then the detection area is improved, but interference between adjacent sensors increases
Solution Approach 1:
The patent implements periodic action by dividing the sensor operation into alternating emitting phases and listening phases. Each sensor emits IR light during its emitting phase and detects reflected light during its listening phase, creating a time-division multiplexed system that eliminates interference between adjacent sensors while maintaining comprehensive detection coverage.
Solution Approach 2:
The controller determines the frequency and phase of interference beams in advance and adjusts the timing of emitting and listening phases proactively to reduce interference. This preliminary adjustment ensures that sensors operate in synchronized coordination before interference issues arise, allowing smooth operation of multiple sensors.
2Speed
If the sensor operates continuously to improve detection responsiveness, then detection speed is improved, but interference from adjacent sensors increases
Solution Approach 1:
The sensor operates in periodic cycles of emitting phases and listening phases rather than continuously. This periodic operation maintains detection responsiveness by ensuring the sensor is actively listening during designated phases while eliminating interference by ensuring only one sensor emits at any given moment through synchronized timing control.
3Reliability
If the emitting phase duration is increased to improve signal strength, then detection reliability is improved, but the listening phase time is reduced
Solution Approach 1:
The system dynamically adjusts the duration and timing of emitting and listening phases based on operational requirements. The controller can optimize the balance between emitting phase duration (for signal strength) and listening phase duration (for detection opportunity) to achieve reliable detection while maintaining adequate listening time.
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 solution enables the IR sensor to operate more efficiently, providing increased flexibility in detection area coverage, reducing interference, and allowing for intelligent adjustments during door operations, thus improving the accuracy and reliability of traffic detection.
Implementation Method 1
one or more emitters configured to emit an emission beam comprising IR light during an emitting phase
Implementation Method 2
one or more receptors configured to receive a reception beam comprising the IR light reflected off of a surface during a listening phase
Data Source
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AI summary
A door sensor (100) may include one or more emitters (300) configured to emit an emission beam comprising IR light during an emitting phase. The door sensor may further include one or more receptors (200) configured to receive a reception beam comprising the IR light reflected off of a surface during a listening phase and an interference beam from an adjacent door sensor. The door sensor may further include a controller operatively coupled to a memory storing computer-readable instructions that, when executed by the controller, cause the controller to: determine one or more of the frequency and phase of the interference beam; determine whether the door sensor should be primary or secondary to the adjacent door sensor; and adjust a timing of one or more of the emitting phase and the listening phase to reduce interference from the adjacent door sensor.