PCB Integrated Motion Sensor with Conductive Sphere
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Solution Overview
Problem
Existing motion sensors are limited in detecting motion in three dimensions, are costly to manufacture, and often require separate mounting and complex designs, making them sensitive to vibrations and unable to indicate directionality of movement.
Innovation Solution
A small form factor motion sensor integrated with a printed circuit board, featuring a conductively plated through hole with hemispheric housings and a conductive sphere that moves across the board, allowing detection of motion in three dimensions and signaling direction through electrical traces and a microcontroller.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a pendulum system is used for motion detection, then motion can be detected, but the system requires a steady surface for mounting and calibration
Solution Approach 1:
The motion sensor is merged with the printed circuit board by integrating the conductive sphere, conductive traces, and housing directly into the PCB structure. The PCB itself serves as both the circuit board and the mounting platform, eliminating the need for separate mounting surfaces and calibration procedures.
2Reliability
If mercury tilt switches are used, then motion detection is achieved, but environmental concerns arise
Solution Approach 1:
The patent replaces hazardous mercury with a harmless conductive sphere made of safe materials. This substitution eliminates environmental toxicity while maintaining the functional principle of conductive ball movement for motion detection.
3Reliability
If Hall effect sensors are used, then motion detection is achieved, but design complexity and manufacturing cost increase
Solution Approach 1:
The patent uses a simple mechanical conductive sphere rolling over conductive traces to generate motion signals, replacing complex Hall effect sensors with magnetic fields and electronic circuitry. This mechanical approach simplifies both design and manufacturing while achieving the same motion detection function.
4Reliability
If prior art motion sensors are used, then motion detection is achieved, but large size requires separate component mounting
Solution Approach 1:
The motion sensor components (conductive sphere, traces, housing) are integrated directly into the printed circuit board structure, eliminating the need for separate sensor housing and mounting apparatus. This reduces overall size and allows direct PCB integration.
5Reliability
If a steel ball rolling over circuits on PCB surface is used, then motion triggering is achieved, but excessive sensitivity to vibration causes undesirable triggering
Solution Approach 1:
The patent positions the conductive sphere within a housing that provides localized containment and guidance. The housing structure and trace configuration are designed to require a minimum threshold of motion force, filtering out minor vibrations while still detecting genuine motion events.
6Reliability
If a tilt sensor with conductive ball rolling on PCB surface is used, then motion detection is achieved, but directionality information in three dimensional spaces is not provided
Solution Approach 1:
The patent extends motion detection to three dimensions by arranging conductive traces and housing features in multiple spatial orientations. The conductive sphere's movement can be detected along X, Y, and Z axes, providing comprehensive directional information through the pattern of trace contacts made during motion.
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 enables cost-effective, vibration-resistant motion detection in three dimensions with directional sensitivity, suitable for various applications including key fob and car alarm systems, without the need for separate mounting or complex components.
Implementation Method 1
An electrically conductive sphere, such as a steel or copper ball, is enclosed within the cavity of the through hole between two housings. The conductive sphere is of a size such that the sphere freely moves across the printed circuit board through hole and between the housings.
Implementation Method 2
A printed circuit board has a through hole, where the through hole is conductively plated on its interior surface and has a trace extending from the conductive interior surface to a micro controller.
Data Source
AI summary
A motion sensor capable of detecting the direction of motion in three dimensions is disclosed. The motion sensor can be built into a printed circuit board allowing for simple and cost effective manufacturing. The motions sensor is designed to utilize a through hole in a printed circuit board, which is capped by on each side by housings creating a cavity where a spherical metal ball can move in three dimensions. This interior surface of the through hole and the housings have conductive element that when in contact with the spherical metal ball close a circuit creating an electrical signal indicative of direction.