Redson Dev · Idea
Smart Shelf Inventory Tracker with Load Sensors
Published May 26, 2026
This project is for small business owners, hobbyists, or even home users who want to automatically track inventory levels without manual counts. By building a smart shelf system with load sensors, you can monitor the real-time quantity of items placed on it, triggering alerts when stock runs low. For example, a small clinic could use this to monitor medical supplies, ensuring critical items are always restocked promptly and reducing the overhead of manual checks.
What you'll need
- ESP32 development board (1)
- HX711 load cell amplifier (4)
- Small platform load cells (e.g., 5kg or 10kg capacity) (4)
- Breadboard (1)
- Jumper wires (assorted)
- USB A-to-micro B cable (1)
- Resistors (e.g., 10k Ohm, 4)
- Sturdy shelf material (e.g., wood, acrylic) (as needed)
Step-by-step
- 01
Assemble Shelf Frame and Mount Sensors
Construct a small, sturdy shelf frame. Mount each load cell in a corner, ensuring it can bear the weight of items placed on the shelf while remaining stable. The load cells should be positioned so that the entire weight of the shelf's contents is distributed evenly across them.
- 02
Wire Load Cells to HX711 Amplifiers
Connect each load cell's four wires to a separate HX711 amplifier module. Typically, E+ goes to E+, E- to E-, A+ to A+, and A- to A-. Ensure all connections are secure to prevent measurement inaccuracies. If using multiple load cells for a single reading, you may need to wire them in a Wheatstone bridge configuration.
- 03
Connect HX711 to ESP32
Connect the `VCC` and `GND` pins of each HX711 to the `3.3V` and `GND` pins on the ESP32. Then, connect the data output pins (`DOUT` and `SCK`) from each HX711 module to distinct digital input pins on the ESP32 (e.g., `DOUT1` to `GPIO16`, `SCK1` to `GPIO17`, and so on for additional sensors). Use a breadboard for cleaner wiring.
- 04
Program ESP32 for Sensor Reading and Wi-Fi
Using the Arduino IDE, install the `HX711` library and the `WiFi` library. Write code to initialize each HX711 module, read raw data, and calibrate the sensors with known weights. Configure the ESP32 to connect to your local Wi-Fi network and publish the processed weight data via MQTT to a local broker or a cloud-based service.
- 05
Set Up Data Monitoring and Alerts
Set up a dashboard (e.g., using Node-RED, Grafana, or a custom web app) to visualize the incoming weight data from the ESP32. Implement logic that triggers an alert (e.g., email, push notification, or an LED indicator) when the total weight drops below a predefined threshold, signaling a low stock level.
Tips
- Calibrate your load cells carefully with exact known weights for accurate readings.
- Consider using shielded cables for load cells if experiencing noisy readings.