🏪 Real-Time Smart Retail Inventory System

A full-stack IoT application that automates retail shelf inventory tracking — from hardware sensor to live web dashboard.

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An ESP32 microcontroller acts as an edge device, constantly measuring physical product stock via an ultrasonic sensor and transmitting telemetry data over Wi-Fi to a C# ASP.NET Core REST API. The backend persists readings in a SQL Server database and serves them to a live web dashboard that auto-updates in real time.

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📸 Project Gallery

Hardware on the shelf	Live web dashboard
Real-time stock monitor	ESP32 wiring diagram

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🎯 Architecture & Tech Stack

 ┌──────────────┐   HTTP POST (JSON)    ┌──────────────────┐        ┌──────────────┐
 │   ESP32 +    │ ───────────────────►  │  ASP.NET Core    │ ◄────► │  SQL Server  │
 │  HC-SR04     │      Wi-Fi            │  REST API (C#)   │        │   Database   │
 │  SSD1306     │                       └────────┬─────────┘        └──────────────┘
 │  Buzzer      │                                │  GET /api/inventory
 └──────────────┘                       ┌────────▼─────────────┐
                                        │   Live Dashboard     │
                                        │ (HTML/CSS/JS/Chart)  │
                                        └──────────────────────┘

1. Backend — ASP.NET Core Web API

Component	Details
Framework	ASP.NET Core with C#
ORM	Entity Framework Core — code-first migrations, SQL Server
Endpoints	POST /api/inventory — receive telemetry from ESP32
	GET /api/inventory/latest — most recent stock reading
	GET /api/inventory/history — time-series of last 20 readings

2. Edge Device — ESP32 Firmware (C++)

Component	Details
MCU	ESP32 — Wi-Fi-enabled microcontroller
Sensor	HC-SR04 ultrasonic — measures product distance on shelf
Display	SSD1306 OLED — shows stock % and boot status locally
Alert	Active buzzer — audible alarm when stock < 10%

3. Frontend — Live Dashboard

Component	Details
Stack	HTML / CSS / JavaScript / Chart.js
Behavior	Auto-polling API to render a real-time stock-level line chart — no manual refresh needed

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💼 Software Engineering Highlights

Practice	Implementation
Secure Credentials	Wi-Fi secrets isolated in a git-ignored secrets.h file — zero sensitive data in version control
Robust Data Mapping	Firmware maps raw distance (cm) → stock percentage (%) with constrained bounds, preventing false negatives
Async / DI Backend	API uses async/await and Dependency Injection following modern enterprise C# patterns
Full-Stack Integration	Bridges low-level C++ memory management on the MCU with high-level C# / SQL Server cloud systems

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🚀 Getting Started

1. Clone the repo

git clone https://github.com/MatheusFerraro/SmartRetail-System.git

2. Run the backend

cd Backend/SmartRetailApi
dotnet ef database update      # apply migrations
dotnet run                      # starts API on https://localhost:5001

3. Wire the ESP32

Connect the components to the Wemos D1 Mini ESP32 as shown below:

Component	Pin	ESP32 GPIO
HC-SR04 Trigger	TRIG	GPIO 14
HC-SR04 Echo	ECHO	GPIO 12
HC-SR04 VCC / GND	—	5V / GND
SSD1306 OLED SDA	SDA	GPIO 21
SSD1306 OLED SCL	SCL	GPIO 22
SSD1306 OLED VCC / GND	—	3.3V / GND
Active Buzzer Signal	+	GPIO 27
Active Buzzer GND	−	GND

4. Flash the firmware

1. Open Firmware/SmartRetail.ino in the Arduino IDE
2. Copy secrets_template.h → secrets.h and fill in your Wi-Fi credentials & server IP
3. Select your ESP32 board and upload

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Developed by Matheus Ferraro — Software Development Student at NBCC