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IoTIntermediateAges 18+An afternoon

Smart Shelf Restocker: Automated Inventory for Small Businesses

Published July 15, 2026

This project is for small business owners, like a local hardware store in Springfield, Illinois, who want to automate inventory monitoring. It uses simple load sensors to detect when products are running low on a shelf, triggering an alert or reorder notification. This helps prevent stockouts and optimizes ordering processes for better customer satisfaction.

What you'll need

  • 1x ESP32 development board
  • 4x HX711 load cell amplifier modules
  • 4x 50kg load cells
  • Jumper wires (male-to-male and male-to-female)
  • Breadboard
  • USB data cable for ESP32
  • Small plastic containers for load cells

Step-by-step

  1. 01

    Assemble Load Sensor Modules

    Attach each 50kg load cell to its respective HX711 amplifier module. Ensure you follow the wiring diagram for the load cell (usually red to E+, black to E-, white to A+, green to A-). Secure the load cells in small plastic containers so they can sit beneath items on a shelf.

  2. 02

    Wire ESP32 to HX711 Modules

    Connect the VCC and GND pins of each HX711 module to the 3.3V and GND pins of your ESP32. For data, connect the DAT pin of each HX711 to a digital input pin on the ESP32 (e.g., GPIO 16, 17, 18, 19) and the SCK pin to another digital input pin (e.g., GPIO 4, 5, 12, 13). Use a breadboard to manage multiple connections.

  3. 03

    Install Arduino IDE & Libraries

    Download and install the Arduino IDE. Add ESP32 board support via the Boards Manager (search for 'esp32'). Install the 'HX711' library by Bogdan Necula using the Library Manager (Sketch > Include Library > Manage Libraries...). This library simplifies reading data from the load cells.

  4. 04

    Program ESP32 for Weight Monitoring

    Write a sketch in the Arduino IDE to initialize and read data from each HX711 connected to your ESP32. Calibrate each load cell by placing a known weight on it to determine its calibration factor. The code should continuously read weight values and, if a value falls below a predefined threshold for an extended period, trigger an alert.

  5. 05

    Implement Alerting Mechanism

    Integrate an alerting mechanism. This could be a simple serial print statement in the Arduino IDE for testing, or expand to connect to a web service via Wi-Fi to send an email or SMS alert to the business owner when stock is low. Use the ESP32's Wi-Fi capabilities to connect to the local network and post data to a simple local web server or a webhook.

Tips

  • Calibrate each load cell carefully with multiple known weights for accuracy.
  • Consider placing multiple sensors per shelf for larger items or varied stock.
  • Power the ESP32 via a stable USB power supply, especially when using Wi-Fi.
#iot#inventory-management#esp32#load-cell#small-business
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