Smart Home Controller

"# Smart Home Controller

Full-stack IoT home automation system with ESP32 firmware, Google Apps Script backend, web dashboard, and Flutter mobile app. Controls 4 AC load channels via TRIAC phase-angle dimming with cloud synchronization, scheduling, and Amazon Alexa voice control.

Project Status

Maturity: Portfolio project / advanced prototype Tested on: ESP32-WROOM-32 with custom TRIAC controller board Known limitations:

• Google Assistant integration (SinricPro) is stubbed but not yet functional
• No automated test suite for firmware or backend
• Flutter app requires manual API URL configuration

What works:

• 4-channel TRIAC phase-angle control with zero-cross detection
• Amazon Alexa voice control (via Espalexa, local network)
• Google Apps Script cloud backend with polling
• Web dashboard with real-time device control
• Flutter mobile app with device control, schedules, and scenes
• OTA firmware updates with rollback protection
• Scene and schedule automation
• WebSocket real-time state sync
• Persistent storage across reboots
• GitHub Actions CI for automated APK builds

Not yet implemented:

• Google Assistant control (SinricPro code is stubbed)
• Automated tests

UI Preview

Web dashboard with real-time device control and system statistics

Quick Start

1. Deploy backend — Copy backend/google-apps-script/ files to a Google Apps Script project and deploy as a web app. See Deployment Guide.
2. Flash firmware — Open firmware/main/main.ino in Arduino IDE, set your Apps Script URL, and upload to ESP32. See Installation Guide.
3. Build mobile app — Run flutter build apk --release in frontend/flutter project/demo/. Or download from Releases.

Documentation

• Deployment Guide — Full system setup
• Installation Guide — Firmware and hardware setup
• Features List — Complete feature documentation
• Hardware Guide — Circuit diagrams and assembly
• OTA Updates — Firmware update procedures
• Mobile App — APK download and build instructions
• Backend & Dashboard — API and web dashboard
• Bill of Materials — Component list and cost
• Security Practices — Security considerations

System Architecture

Components

• Multi-core architecture: Time-critical TRIAC control on Core 1, network operations on Core 0
• Amazon Alexa: Voice control via Espalexa (local network discovery)
• Cloud backend: Google Apps Script + Google Sheets for remote control and configuration
• Web dashboard: HTML5 control panel served from Apps Script
• Flutter mobile app: Cross-platform app with device control, schedules, and scenes
• OTA updates: Over-the-air firmware updates with rollback protection
• Scenes & schedules: Automation and preset device combinations
• Safety features: Watchdog timers, zero-cross monitoring, auto-shutoff
• Persistent storage: Configuration and state retention across reboots

Repository Structure

smarthome-controller/
├── firmware/                      # ESP32 firmware code
│   ├── main/                     # Main 4-channel controller firmware
│   └── mini_controller/          # Simplified single-channel variant
├── backend/                       # Cloud backend
│   └── google-apps-script/       # Google Apps Script API + web dashboard
├── frontend/                      # Mobile app
│   └── flutter project/demo/     # Flutter cross-platform app
├── hardware/                      # Hardware design files
│   ├── pcb/                      # KiCad PCB design
│   ├── schematics/               # Circuit diagrams
│   └── bom/                      # Bill of materials
├── app/                          # Android APK builds (via CI)
├── docs/                         # Additional documentation
├── DEPLOYMENT.md                 # Full system deployment guide
├── INSTALL.md                    # Firmware installation and setup
├── FEATURES.md                   # Feature list
├── OTA_GUIDE.md                  # OTA update procedures
└── CHANGELOG.md                  # Version history

Hardware Requirements

ESP32 Module

• ESP32-WROOM-32 or compatible
• Minimum 4MB flash
• Dual-core operation

TRIAC Controller Hardware

• 4x TRIAC channels (BT136 or similar)
• Zero-cross detection circuit
• MOC3021/3041 optocouplers
• 5V power supply

Pin Configuration

Software Architecture

Core Separation

CORE 1 (PRO_CPU) - TIME-CRITICAL:
├── Zero-cross detection ISR (RISING edge @ GPIO13)
├── Hardware timer ISR for phase-angle control (100µs intervals)
├── TRIAC firing with <50µs accuracy
└── NO blocking calls or network operations

CORE 0 (APP_CPU) - CONNECTIVITY:
├── WiFi management with auto-reconnect
├── Google Apps Script cloud polling (2.5s interval)
├── Alexa voice assistant handling
├── Physical switch debouncing
├── Web servers (port 80, 8080, WebSocket 81)
├── OTA update handling
├── Schedule execution
├── Scene activation
├── Fade transitions
└── Watchdog monitoring (15s timeout)

Data Flow

Physical Switch → Debounce → Device State Update → TRIAC Control
                                      ↓
                            Cloud Sync / WebSocket Broadcast

Voice Command → Alexa → Device State Update → TRIAC Control
                                      ↓
                            Cloud Sync / WebSocket Broadcast

Local REST API (Port 8080)

WebSocket on port 81 provides real-time device state updates.

License

MIT License — See LICENSE file for details.

Support

• Issues: https://github.com/Gokul3611/smarthome-controller/issues"