Retroreflective Optical Occupant Detection System
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Solution Overview
Problem
Existing vehicle alert systems for detecting unattended children or pets are unreliable, leading to frequent false alarms and failure to alert when necessary, which discourages manufacturers from integrating these systems into vehicles due to liability concerns and loss of goodwill.
Innovation Solution
An on-board alert system using infrared emitters and retroreflectors to detect the presence of occupants, with additional sensors for cargo and temperature monitoring, triggering alarms through flashing lights, audible alerts, and cellular communications if an occupant is left unattended, and incorporating a delay to prevent false alarms.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Difficulty of detecting and measuring
If complex sensors and switches are used to detect child presence, then detection capability is improved, but system reliability deteriorates due to false alarms and failures
Solution Approach 1:
The system divides the detection task into multiple independent optical zones, each monitored by separate emitters and detectors. Instead of relying on a single complex sensor, the patent uses multiple simple optical beams segmenting the vehicle interior space, where each beam independently detects occupancy in its specific zone, thereby improving reliability through redundancy and simplicity
Solution Approach 2:
The patent replaces mechanical sensors and switches with an optical detection system using infrared emitters and retroreflectors. This substitution eliminates the mechanical complexity and contact wear issues of traditional sensors, providing a more reliable detection mechanism that is less prone to false alarms while maintaining effective child presence detection
2Measurement precision
If multiple detection methods are implemented, then detection accuracy is improved, but device complexity increases
Solution Approach 1:
The optical detection system serves multiple functions simultaneously: it detects child presence, determines seat occupancy status, and provides the basis for alarm activation. This multi-functionality is achieved through a unified optical architecture using emitters, retroreflectors, and detectors that can interpret different reflection patterns to derive multiple pieces of information, thereby improving detection accuracy without proportionally increasing system complexity
Solution Approach 2:
The retroreflector serves as an intermediary element that enables the optical detection system to function. By placing retroreflectors on or near seats, the system creates reliable reflection paths that allow the emitter-detector pairs to accurately detect occupancy. This intermediary component simplifies the overall system design compared to using complex active sensors in each seat, while maintaining high detection precision
3Speed
If immediate alarm is triggered upon detection, then response time is improved, but false alarm rate increases
Solution Approach 1:
The system implements a time delay mechanism that activates the alarm only after a predetermined period following detection of an unattended occupant. This preliminary waiting period allows the system to confirm the situation is genuine and not a transient condition, thereby reducing false alarms while still providing timely warning. The delay is built into the control logic as a standard preprocessing step before alarm activation
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
The system effectively reduces false alarms and ensures timely alerts for unattended children or pets, enhancing safety by integrating reliable detection and communication mechanisms within the vehicle's framework.
Implementation Method 1
one or more optical (infrared) emitters, each of which emits an infrared beam across a path in the vehicle
Implementation Method 2
retroreflectors are positioned on structures of the vehicle in the path. If an occupant is seated in the path, the infrared beam is not reflected back to the detector
Data Source
AI summary
An alert system detects the presence of occupants in a vehicle using optical sensors comprised of (infrared) emitters and photodetectors. Each sensor emits a beam across a path in proximity to a seat. Retroreflectors are positioned in the path. A seated occupant blocks the path and prevents reflection. If the path adjacent to a baby's seat is blocked and the path adjacent to the driver's seat is not blocked, an alarm event is triggered. After a delay, voice and text messages and audible and visible output are generated.