After research, we found that in regular supermarkets, employees are mainly divided into positions such as stock clerks, cashiers, security personnel, and sales assistants. In an unmanned supermarket, tasks like checkout, security, and sales assistance can all be handled by machines. After analysis, it appears as shown in the image below, but currently, stock management still requires personnel to complete it personally:

Especially the handling of near-expiration products and timely replenishment of goods are essential for ensuring the quality of supermarket products. I believe no one wants to buy expired products. Therefore, I created a shelf management system that allows stock clerks to promptly replenish products and handle expired items, making their work easier. Through network management, one can remotely view the quantity and shelf life of products. If stock management can truly be automated, we can also transmit data from the database to achieve automatic stock management functionality.

Main Functions Implemented:

1. Product Pricing: By scanning the product label with NFC, the price of the purchased product is calculated, and the corresponding product quantity in the database is reduced. If the quantity of products on the shelf falls below a certain value, it will alert our stock clerks to replenish the stock.

2. Self-Checkout: Rechargeable NFC shopping cards can be used to complete payment automatically when scanned.

3. Inventory Management: Real-time visibility of inventory changes in the backend, achieved through a program for inventory management.

4. Discounts and Promotions: During real-time monitoring, if a product’s production date in the database is nearing, it will also notify stock clerks to apply discounts, allowing remote modification of product prices to complete the discount process.

• Arduino UNO R3 X1

• Arduino UNO Expansion Board X1

• Gravity: UART OBLOQ – IoT Module X1

• Gravity: UART & I2C NFC Module X1

• Gravity: I2C OLED-2864 Display X1

After brainstorming, we decided to create a shelf management system.

Based on experience, we need to first write the program before proceeding with the design, as this makes it easier to control the size of the work and avoids situations where there is no place to put sensors after the design is completed.

Once the selected hardware is connected, we begin to complete the program step by step.

First, we determine the ID of the NFC card in hand, and then perform different operations based on the detected ID. There are a total of three tags: a large one simulating a shopping card and two small ones simulating products.

Since all the programs are related to the database, we first collected some common products and filled in their information in the database, including product prices, shelf life, shelf quantity, and inventory quantity.

After filling in the database, we can gradually complete our program. The first card acts as bread 1, and when the NFC detects it, it will read the product price from the database and display it on the first line of the screen, setting a variable to calculate the total price of our products displayed on the second line, and then reducing the quantity in the database by 1.

The second product card works the same way. If there are more cards, we can also write the product names corresponding to the card IDs into the database, so that when the product ID is read, we can obtain its name, thereby reducing the complexity of the program.

For the third shopping card, once detected, it reads the shopping card balance and displays it on the third line, then calculates the remaining balance after shopping and displays it on the fourth line, updating the new balance in the database. If the balance is insufficient, it will issue a warning.

This is the thought process behind the Arduino program.

This project is designed for the convenience of stock clerks, so I created a very intuitive management interface in Mind+’s real-time mode, allowing direct completion of functions such as updating product production dates, restocking, and modifying prices.

I found product materials online and began programming.

When we click on a role, we can achieve the expected functions: update production dates, restock shelves, replenish inventory, and modify prices.

These operations are closely related to the database, as all product information in our store is retrieved from the database.

In special situations, the program should notify our staff in real-time, such as when products expire or when the shelf products are insufficient.

I set different reminder methods based on various situations.

When a product expires, it directly jumps to the expired product page, and the product becomes highlighted, while insufficient shelf products will darken.

We can also actively query product information. To prevent obstructing other products, I used the space key to display the product’s information.

With the program basically completed, we can proceed to the design phase. Using laser cutting saves time, and drawing is also quite convenient.

Drawing was done using MakerBrush, which allows for the drawing of three-dimensional structures, but for detail work, we relied on other software for editing. The area left at 1 is for ease of detail editing, as shown in the general model:

Imported into laserbox for detail modification, and then arranged for cutting.

Started assembly, piecing together the external frame according to the 3D diagram.

We decided to add some small decorations and items inside the model. At the same time, I also designed a shopping card:

After assembling and debugging is completed, please see the video demonstration below.

Source Code:

The software source code is 1.sb3 and can be opened with Mind+1.7.1.

There are modes for uploading and real-time. After connecting the hardware according to the wiring diagram, modify the network hotspot of the upload mode program and upload it to the Arduino board.

In real-time mode, click the green flag to start running. Click on a product and follow the prompts to complete the corresponding management operations. When the mouse hovers over a product and the space key is pressed, the basic information of the product will be displayed. If the page jumps to another page and the product turns white or black, do not worry; it is reminding you to replenish stock or clean up near-expiration products.

Structural Design Files:

The file is a three-dimensional design drawing that can be imported, viewed, or modified through Botcraft2 (datui.tv).

The file <5 final cutting.lq> is the final cutting file after detail modification through laserbox, which can be viewed through laserbox, but requires the corresponding laser cutting machine for cutting.

Wiring Diagram:

The wiring diagram is straightforward, with only three sensors in total.

NFC is an IIC interface, the 12864 display is an IIC interface, and the OBLOQ IoT is a serial port.

For IIC, SDA connects to SDA, SCL connects to SCL. If more connections are needed, A4 connects to SDA, A5 connects to SCL.

For serial, RX connects to TX, TX connects to RX. Remember to disconnect the serial connection when uploading the program.

The wiring is shown in the image below: