Pressure Sensor Mat With Flexible Switches for Child Seat Detection
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Solution Overview
Problem
Current pressure sensors used to detect a child's presence on a car seat are complex and costly, exceeding the precision requirements for this application while being economically impractical.
Innovation Solution
A pressure sensor comprising a soft mat with a sensitive element made of polymeric materials and an electronic control unit, featuring flexible portions that deform and connect electrical conductors only when a pre-set threshold weight is applied, allowing for reliable and economical detection of a person's presence on a seat.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If complex pressure sensors are used to detect child presence on car seats, then detection accuracy is improved, but cost increases excessively
Solution Approach 1:
The sensor is divided into multiple independent flexible portions (sensing elements) arranged in a matrix pattern on the soft mat. Each flexible portion independently detects pressure at its location, and the electronic control unit processes signals from multiple elements to determine overall presence. This segmentation allows using simple, low-cost flexible portions while achieving reliable detection through collective information from multiple points.
Solution Approach 2:
The patent replaces expensive, complex pressure sensors with inexpensive flexible portions made from simple conductive materials and soft matting. These flexible portions are designed to be economical to manufacture, using basic materials like conductive fabric or thin conductive layers that can be produced at very low cost while still providing sufficient detection capability for the application.
2Ease of manufacture
If simple pressure sensors are used to reduce cost, then manufacturing economy is improved, but detection reliability deteriorates
Solution Approach 1:
Multiple simple flexible portions are merged into a unified sensing system arranged in a matrix pattern. The electronic control unit combines signals from all flexible portions to make a determination about child presence. This merging approach maintains simplicity and low cost of individual elements while achieving high reliability through the collective detection capability of the entire array.
Solution Approach 2:
The electronic control unit continuously monitors signals from all flexible portions and uses this feedback to determine whether a child is present on the seat. The system processes the combined information from multiple sensing points to make a reliable presence detection decision, ensuring that simple individual elements work together to achieve dependable overall performance.
3Reliability
If multiple sensing elements are used to improve detection reliability, then detection accuracy is improved, but device complexity increases
Solution Approach 1:
The soft mat serves multiple functions: it provides comfortable cushioning for the child while simultaneously serving as the substrate for the pressure sensing elements. The flexible portions are integrated directly into the soft mat structure, combining seating functionality with detection functionality. This multi-functionality reduces overall system complexity by eliminating separate components.
Solution Approach 2:
The sensing elements are constructed using flexible thin films or conductive layers integrated into the soft mat material. This approach maintains the flexibility and comfort of the seating surface while incorporating the sensing capability, avoiding rigid or complex sensor structures that would increase device complexity.
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 solution provides a cost-effective and reliable means to detect the presence of a person on a seat, enabling the prevention of children being left unattended in vehicles by transmitting an alarm signal when the child remains on the seat while the parent moves away.
Implementation Method 1
featuring flexible portions that deform and connect electrical conductors only when a pre-set threshold weight is applied
Data Source
Figure 1~2
Figure 3~4
AI summary
Described herein is a pressure sensor (100), comprising: a first layer (115) of electrically insulating material, a second layer (120) of electrically insulating material superposed on the first layer, and at least one electrical switch, wherein said electric switch comprises: at least one electrical contact(145, 150) associated with the first layer (115), and an electrical conductor (140) associated with a flexible portion (125) of the second layer (120), which is separate from the first layer (115) and is directly superposed on said electrical contacts (145, 150).