Vending Machine Inventory Detection Using Single Optical Sensor
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Solution Overview
Problem
Existing vending machines require multiple sensors for each product chute, making them expensive and inflexible, and often refill only after an empty state is detected, limiting their operational flexibility and increasing costs.
Innovation Solution
A vending machine with a single optical sensor and control unit that uses image data to determine product quantities by analyzing brightness curves, allowing for the detection of different types of products and flexible operation, and can be retrofitted to existing machines.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple sensors are used for each product compartment, then product inventory detection reliability is improved, but device cost and complexity increase
Solution Approach 1:
Multiple product compartments are monitored by a single sensor. The sensor captures images of multiple compartments simultaneously, and the control unit processes the single image to determine inventory levels across all monitored compartments, replacing the need for multiple individual sensors
Solution Approach 2:
A single sensor serves multiple functions by monitoring inventory in multiple different product compartments. The sensor and control unit can identify and count products across various compartments, making the system universal rather than dedicated to a single compartment
2Device complexity
If each compartment is filled with the same type of goods, then sensor linkage to specific products is simplified, but vending machine flexibility is reduced
Solution Approach 1:
The system detects products based on their visual characteristics including color, shape, and packaging features captured in the image. The control unit analyzes these visual properties to identify different product types, enabling flexible product assignment without requiring uniform goods in each compartment
Solution Approach 2:
The control unit creates a digital representation of the physical compartment layout and product positions from the captured image. This virtual model allows the system to track and manage different product types in different compartments without physical reconfiguration
3Device complexity
If refilling is performed only after vacancy detection, then sensor usage is minimized, but operational flexibility and productivity are reduced
Solution Approach 1:
The control unit continuously monitors product inventory levels by processing images from the sensor and provides real-time feedback on stock status. This continuous monitoring enables proactive refilling decisions based on actual inventory levels rather than waiting for complete vacancy detection
Solution Approach 2:
The system can detect when product inventory is running low before the compartment is completely empty. This preliminary detection allows for advance refilling actions to be taken, preventing operational disruptions and maintaining continuous product availability
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 provides a cost-effective and flexible method for determining product inventory, enabling timely refills and reducing the need for multiple sensors, thus enhancing operational flexibility and reducing costs.
Implementation Method 1
an optical sensor by means of which image data of at least one storage unit and the goods contained therein are captured
Implementation Method 2
The control unit calculates a brightness curve with brightness minima and maxima from this image data. Based on the number of brightness minima, the control unit determines the number of items in the storage unit
Data Source
Figure 1a~1c
Figure 2a~2d
Figure 3a~3d
AI summary
The invention relates to a method for operating a vending machine with at least one storage unit (1, 7) in which a plurality of individual goods (2, 2') are stored, wherein the vending machine has a control unit and at least one optical sensor, wherein the optical sensor records image data of the at least one storage unit (1, 7) and the goods (2, 2') contained therein, wherein the control unit determines from the image data of the optical sensor the number of goods (2, 2') that are located in the at least one storage unit (1, 7).