Capacitive Trunk Access Sensing With Dual Detection Zones
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Solution Overview
Problem
Existing hands-free access systems for vehicle trunks are risky or dangerous, especially for users carrying objects, elderly individuals, or those wearing high heels, and are not compatible with all vehicle types, particularly higher vehicles like pick-up trucks and SUVs.
Innovation Solution
A device using a single electrode capacitive sensor with separate metal surfaces outside a sealed housing to create two detection areas, analyzing capacitance variations for secure hands-free access, without requiring intrusive modifications to the vehicle.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single electrode sensor is used, then device complexity is reduced, but detection precision deteriorates
Solution Approach 1:
The patent divides the detection function into two separate detection areas (first and second detection areas) formed by the single electrode at different locations on the vehicle. This segmentation allows the system to detect the sequential passage of a limb through multiple zones, enabling accurate movement detection while maintaining a simple single-electrode structure.
Solution Approach 2:
The patent transitions from detecting movement in one dimension to detecting movement across multiple dimensions by positioning the single electrode to create two separate detection areas in different spatial locations. The control unit analyzes the temporal sequence of signals from these areas to determine limb movement, effectively adding a temporal dimension to the detection process.
2Ease of operation
If hands-free access is implemented, then ease of operation is improved, but safety deteriorates due to limb lifting requirements
Solution Approach 1:
The patent replaces the mechanical action of lifting a limb (as required by foot-based sensors) with an electrical/capacitive detection system. The single electrode detects the presence and movement of a limb through capacitance changes without requiring the user to perform potentially dangerous mechanical movements, thus maintaining hands-free operation while eliminating safety risks.
3Device complexity
If multiple detection areas are created with a single electrode, then device complexity is reduced, but manufacturing precision requirements increase
Solution Approach 1:
The patent makes the single electrode serve multiple functions by positioning it to create two distinct detection areas. This multi-functional use of the electrode reduces the number of components needed while the control unit's ability to analyze signals from both areas provides robust detection that can accommodate reasonable manufacturing tolerances.
Solution Approach 2:
The control unit receives feedback signals from the single electrode at different times as a limb passes through the first and second detection areas. This temporal feedback pattern allows the system to accurately determine limb movement and direction, compensating for variations in electrode positioning and reducing the impact of manufacturing precision limitations.
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
Enables safe and reliable hands-free trunk opening without lifting limbs, compatible with various vehicle types, using a single electrode to generate multiple detection areas without altering the sealed housing.
Implementation Method 1
an approach and/or contact detection sensor (10) comprising a single electrode (E1) and analysis means for analyzing said variations in capacitance of the electrode
Data Source
AI summary
Disclosed is a device for opening/closing an opening element of a motor vehicle by detecting movement of a users limb, the device including an approach and/or contact detection sensor including a single electrode and an analyzer for analyzing the variations in capacitance of the electrode, and an opening element opening/closing control unit. The device also includes: a sealed housing including first and second metal surfaces; and a unit for detecting a predetermined form of the variations of the electrode, exhibiting a succession of a predetermined number of peaks of predetermined amplitude within a predetermined period; the first and second surface being separate, and the electrode being located outside the sealed housing, in such a way that the electrode is coupled electrically to the at least one first surface and to the at least one second surface so as to create at least two approach and/or contact detection areas.