Capacitive Mattress Perimeter Sensing for Reliable Bed Presence Detection
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Solution Overview
Problem
Traditional presence-sensing technologies for automated furniture, such as bed systems, are prone to inaccuracies due to shifting or bending sensors and are often too expensive or impractical for manufacturing, leading to issues with detecting user presence reliably.
Innovation Solution
Incorporating a capacitive component, such as a capacitive wire, into the perimeter of furniture items, including automated bedding systems, which uses a processor to determine presence based on changes in capacitance, providing a more reliable and cost-effective solution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional presence-sensing switches are routed around the perimeter of a mattress, then presence detection is enabled, but the switches shift or bend during bed articulation causing inaccurate readings
Solution Approach 1:
The patent replaces mechanical presence-sensing switches with a capacitive sensing system that uses electrical fields to detect presence. The capacitive sensor includes a conductive member (such as a wire or tape) coupled to a sensor circuit that measures changes in capacitance or impedance when a person approaches or contacts the bed, eliminating the need for mechanical switches that shift or bend during articulation.
2Reliability
If traditional presence-sensing switches are used, then presence detection is achieved, but additional analog components such as sensors and oscillators are required increasing device complexity
Solution Approach 1:
The patent merges the sensing element and the evaluation circuitry into an integrated capacitive sensor system. The conductive member serves both as the sensing element and as part of the signal path to the sensor circuit, eliminating the need for separate mechanical switches, additional sensors, and oscillators required by traditional systems.
Solution Approach 2:
The capacitive sensing system replaces complex mechanical switch assemblies with a simpler electrical field-based detection system that uses capacitance measurements to detect presence, reducing the number of analog components needed.
3Extent of automation
If pressure pads or switches are used for presence detection, then automated response can be triggered, but the switches may fail to be triggered or may be too sensitive causing false activation
Solution Approach 1:
The patent replaces pressure-sensitive mechanical switches with a capacitive sensing system that detects changes in electrical field capacitance. This allows for adjustable sensitivity thresholds in the sensor circuit to distinguish between genuine presence (person approaching or contacting the bed) and false triggers (minor movements or environmental factors), improving detection reliability while maintaining automated response capability.
4Reliability
If traditional presence-sensing switches are used, then presence detection is enabled, but manufacturing cost and practicality are reduced
Solution Approach 1:
The capacitive sensor system uses simple conductive members (such as wires or tapes) that are inexpensive and easy to manufacture compared to mechanical switch assemblies. The conductive member can be easily integrated into the bed structure or mattress cover, and the sensor circuit requires minimal components, making the overall system more cost-effective and practical for manufacturing.
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 capacitive presence-detection system effectively addresses the inaccuracies and practicality issues of traditional methods by providing a reliable and cost-effective means to detect user presence, reducing false readings and improving the functionality of automated furniture systems.
Implementation Method 1
a capacitive component adapted to have a capacitance based on proximity of a body to the capacitive component
Data Source
AI summary
A system and method for incorporating presence-sensing technology into furniture is provided. More particularly, the invention relates to incorporating a conductive medium into the periphery of a furniture item, such as an adjustable bed, for detecting the presence of a user or other body. The bed includes a mattress with a covering material and a tape edge surrounding the perimeter of the mattress. A capacitive wire is coupled the tape edge, and is adapted to have a voltage based on proximity of an object to the capacitive wire. The bed also includes a processor coupled to the capacitive wire. The processor receives information provided by the capacitive wire, determines when a change in voltage satisfies a threshold, and indicates whether presence is detected. Based on a determination of presence, or lack of presence, a variety of corresponding features of the adjustable bed may be activated.