Capacitive Shelf Sensor Array for Low-Interference Item Tracking

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Solution Overview

Problem

Current inventory management systems face challenges in accurately monitoring and tracking the movement of items within facilities, particularly in environments with dense inventory locations, where interference between sensors can occur, leading to inaccurate data and inefficiencies in inventory tracking.

Innovation Solution

The implementation of a system using capacitive sensors with conductive elements arranged in specific layouts and seed values to minimize interference, combined with an analysis module that processes data from multiple sensors to generate interaction data, enabling precise tracking of item movements and inventory levels.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If sensors are placed in dense inventory locations to improve monitoring coverage, then measurement precision improves, but interference between sensors increases causing measurement errors

Engineering Contradiction:
Improveinventory tracking accuracyVSAvoidsensor interference
Core Design Contradiction:
Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The sensor array is divided into multiple independently controllable sensor elements that can be selectively activated. This segmentation allows the system to divide the monitoring area into zones and activate only the necessary sensors, reducing overall interference while maintaining measurement precision in dense inventory locations

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Sensors are activated in periodic sequences rather than simultaneously, with each sensor element operating at different time intervals. This periodic activation reduces interference between adjacent sensors while maintaining continuous monitoring coverage, resolving the contradiction between measurement precision and interference reduction

Inventive Principle:
Principle #19Periodic action

2Productivity

If multiple capacitive sensors are operated simultaneously to improve productivity, then inventory monitoring efficiency improves, but interference between sensors increases leading to inaccurate data

Engineering Contradiction:
Improveinventory monitoring efficiencyVSAvoiddata accuracy
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The system implements periodic operation of capacitive sensors in sequential batches rather than simultaneous operation. Different sensor groups are activated at different time periods, which maintains high monitoring efficiency through continuous scanning while eliminating interference that would compromise data accuracy

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The sensor operation schedule is dynamically adjusted based on inventory activity levels and interference patterns. The system can increase sensor activation frequency during high-activity periods while maintaining data integrity through adaptive timing, thus improving productivity without sacrificing reliability

Inventive Principle:
Principle #15Dynamics

3Measurement precision

If sensor activation sequence is randomized to minimize interference, then measurement precision improves, but system complexity increases due to coordination requirements

Engineering Contradiction:
Improveinteraction location accuracyVSAvoidsensor coordination complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

Instead of fully random activation, the system uses predetermined periodic sequences with deterministic timing patterns. This approach maintains measurement precision by ensuring non-conflicting activation schedules while reducing coordination complexity through repeatable, predictable sequences that are easier to implement and debug

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The sensor activation sequences are pre-calculated and stored as lookup tables based on sensor positions and potential interference patterns. This preliminary preparation eliminates the need for complex real-time randomization logic, reducing system complexity while maintaining the precision benefits of non-simultaneous activation

Inventive Principle:
Principle #10Preliminary action

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

This solution allows for accurate and efficient monitoring of inventory movements, reducing interference between sensors and improving the accuracy of inventory tracking, enabling real-time updates and efficient facility operations.

Implementation Method 1

a capacitive sensor including a conductive element and a capacitive sensor module configured to generate capacitance data based on a change in capacitance of the conductive element

Methodology Applied
Scientific EffectCapacitance: Capacitance

Data Source

PatentUS10262294B1Location estimation using array of capacitive sensors
Publication Date: 2019.04.16 AMAZON TECH INC
  • US10262294B1 patent drawing
  • US10262294B1 patent drawing
  • US10262294B1 patent drawing

AI summary

A user may pick, place, or move an item at an inventory location, such as a shelf. Described are techniques to determine a location of one or more of an object, such as an item or a user, with respect to an array of capacitive sensors. The array may be part of the shelf. As an item is added to, moved or removed from the shelf, when the user's hand is near the shelf, and so forth, capacitance measured by one or more of the sensors in the array may change. Based on these changes, a location relative to the sensor array may be determined. A particular shelf may have different areas, each designated as holding a different type of item. The location information obtained from the capacitive sensors may be used to determine which item on the shelf was interacted with.