Overview / Objective

Design and deploy a scalable, low-power smart parking system using ESP32 microcontrollers and HC-SR04 ultrasonic sensors to detect vehicle presence in individual parking slots. The system communicates via MQTT to a cloud-based device management platform that supports real-time monitoring, configuration updates, and OTA firmware upgrades.

Solution

Edge Device Layer

• ESP32 MCU: Controls sensor readings, LED indicators, and communication.
• HC-SR04 Ultrasonic Sensor: Detects vehicle presence based on distance measurement.
• RGB LED: Indicates slot status (green = free, red = occupied).
• Power Optimization:
  • Deep sleep mode between reading
  • Wake-up on timer or external trigger
  • Optional solar + battery setup for outdoor deployment

Communication Layer

• Wi-Fi: ESP32 connects to local router or mesh gateway.
• MQTT Protocol: Lightweight publish/subscribe model for real-time data transfer.

Cloud Device Management Platform

• MQTT Broker: Handles incoming messages from ESP32 devices.
• Device Registry: Tracks device metadata, location, firmware version.
• Configuration Service: Updates thresholds, reporting intervals remotely.
• OTA Firmware Update Service: Delivers new firmware binaries to devices.
• API Backend: RESTful interface for dashboard and mobile app integration.

Dashboard Layer

• Web Dashboard:
  • Real-time parking slot map
  • Device health and status
  • OTA update controls
  • Analytics: occupancy trends, peak usage

Database Layer

• Stores:
  • Device metadata
  • Slot status history
  • Firmware versions
  • Configuration profiles

Benefits

• Real-Time Visibility: Live updates on parking availability
• Remote Management: Configure and update devices from anywhere
• Low Power Consumption: Efficient operation with deep sleep and minimal data transmission
• Scalability: Easily deployable across multiple sites
• Cost-Effective: Uses affordable components with open-source firmware
• Maintainability: OTA updates reduce manual servicing

Tools and Technologies

Hardware

• ESP32 DevKitC / WROOM
• HC-SR04 Ultrasonic Sensor
• RGB LED
• Power supply (DC)

Firmware

• ESP-IDF
• MQTT client library
• HTTP OTA update library
• Sensor drivers

Cloud / Backend

• MQTT Broker ( Mosquitto)
• REST API backend (Python)
• OTA firmware hosting (Firebase Storage)

Database

• PostgreSQL

Dashboard

• React JS
• MQTT-over-Web
• Admin panel for OTA & device management