Complete IoT solution for intelligent fan automation, real-time monitoring, and mobile control
SmartFan is a comprehensive IoT ecosystem that transforms any standard stand fan into an intelligent, automated climate control system. Built with a dual-ESP architecture (ESP8266 + ESP32) and a modern Android app, it delivers seamless temperature-based automation, real-time monitoring, and cloud integration.
- ESP8266: WiFi Manager + Firebase Handler — Manages WiFi, cloud database, and push notifications
- ESP32: Sensor Reader + Hardware Controller — Handles DHT22, ACS712 (with voltage divider), TRIAC fan control, and safety monitoring (220V fixed voltage)
- Serial Communication: Custom protocol for real-time data exchange between microcontrollers at 9600 baud (ESP8266: SoftwareSerial, ESP32: HardwareSerial2)
- Intelligent Automation: Temperature-based fan speed control (auto/manual)
- Real-time Monitoring: Live temperature, humidity, voltage, current, power, and energy tracking
- Modular Dual-ESP: ESP8266 (WiFi/Firebase) + ESP32 (Sensors/Hardware)
- Robust Serial Protocol: Reliable, fault-tolerant inter-ESP communication
- Modern Android App: Material Design 3, animated gauges, power analytics, device management
- Cloud Integration: Firebase for data logging, user authentication, remote control, and push notifications
- Easy Setup: WiFiManager captive portal, app-based WiFi config, and hardware reset
- Power Monitoring: ACS712 (current with voltage divider) with fixed 220V for calculations, safety alerts and analytics
- Smart Notifications: Push notifications for temperature/power alerts and system status
The SmartFan project includes custom-designed 3D printed enclosures for housing the electronics and sensors. All models are provided as both STL files (for printing) and G-code files (pre-sliced for Creality Ender 3 V3 SE).
Main Board Case Base
- File:
SmartFan_Board_Case_Base.stl/CE3V3SE_SmartFan_Board_Case_1.gcode - Purpose: Houses the main ESP8266 and ESP32 boards
- Features: Ventilation slots, mounting posts for PCBs, cable management
- Dimensions: Designed for dual ESP board layout
Board Case Base Alternative
- File:
SmartFan_Board_Case_Base_2.stl/CE3V3SE_SmartFan_Board_Case_Base_2.gcode - Purpose: Alternative base design with modified layout
- Features: Different mounting configuration for compact installations
Board Case Cover
- File:
SmartFan_Board_Case_Cover.stl/CE3V3SE_SmartFan_Board_Case_Cover.gcode - Purpose: Protective cover for the main board case
- Features: Access ports for connectors, LED indicators, reset button
- Design: Snap-fit or screw mounting options
Sensor TRIAC Case
- File:
SmartFan_Sensor_Triac_Case.stl/CE3V3SE_SmartFan_Sensor_Triac_Case.gcode - Purpose: Houses ACS712 current sensor and TRIAC control module
- Features: Heat dissipation fins, isolated compartments for safety
- Safety: Proper isolation between low-voltage and AC components
Sensor TRIAC Case Cover
- File:
SmartFan_Sensor_Triac_Case_Cover.stl/CE3V3SE_SmartFan_Sensor_Triac_Case_Cover.gcode - Purpose: Protective cover with safety features
- Features: Warning labels area, secure fastening, cable strain relief
Smart Fan Selector Cover
- File:
Smart_Fan_Selector_Cover.stl/CE3V3SE_Smart_Fan_Selector_Cover.gcode - Purpose: Replacement cover for fan control interface
- Features: Professional finish, mounting holes for indicators
- Integration: Designed to replace standard fan control panel
Fully Assembled System
- Description: Complete system assembly showing all components in place
- Layout: Demonstrates proper cable management and component placement
System Back View
- Description: Rear view showing connections and ventilation
- Features: Cable routing, heat dissipation considerations
Component Overview
- Description: Individual component layout and identification
- Reference: Component placement guide for assembly
Recommended Print Settings:
- Layer Height: 0.2mm
- Infill: 20-30%
- Support: Required for overhangs >45°
- Material: PLA or PETG (ABS for high-temperature areas)
- Nozzle Temperature: 200-210°C (PLA), 240-250°C (PETG)
- Bed Temperature: 60°C (PLA), 80°C (PETG)
G-code Files: Pre-sliced for Creality Ender 3 V3 SE with optimized settings
The complete wiring diagram shows the interconnections between all components:
- ESP8266 and ESP32 boards with serial communication links
- DHT22 temperature/humidity sensor connection
- ACS712 current sensor with voltage divider circuit
- TRIAC module for AC fan control with zero-cross detection
- Piezo buzzer for alert notifications
- Power supply connections and safety considerations
- WiFi reset button and status LED
Fritzing Project: The original circuit design is available as diagram/SmartFan.fzz for editing and customization.
- ZMPT101B Voltage Sensor: Removed from hardware design, using fixed 220V value for power calculations
- GPIO35 Freed: Pin now available for future expansion or additional sensors (ESP32)
- GPIO34 Active: ACS712 current sensor moved to GPIO34 with voltage divider implementation
- Simplified Wiring: Reduced component count and power consumption
- Maintained Functionality: Power monitoring still accurate with current sensor + voltage divider + fixed voltage
- Voltage Divider Circuit: Added 1kΩ + 2kΩ resistor network for ACS712 signal conditioning
- Improved Accuracy: Voltage divider factor 2.43 compensates for signal attenuation and improves ADC range utilization
- Enhanced Stability: Better signal conditioning reduces noise and improves measurement reliability
- Calibrated RMS Measurement: Updated CURRENTSensor class with voltage divider factor integration
- Backward Compatibility: Maintains legacy readCurrent() method while adding improved readCurrentRMS()
ESP32 Pin Assignments (Latest):
- DHT22 Sensor: GPIO4 (unchanged)
- Current Sensor: GPIO34 (moved from GPIO35)
- Buzzer: GPIO25 (unchanged)
- TRIAC Output: GPIO18 (updated for RobotDyn compatibility)
- Zero Cross Detection: GPIO5 (updated for RobotDyn compatibility)
- Serial Communication: GPIO16 (RX), GPIO17 (TX)
ESP8266 Pin Assignments:
- WiFi Reset Button: D5 (updated from D3)
- Serial Communication: D6 (RX), D7 (TX)
- LED Indicator: D4
- Serial Communication (ESP8266 ↔ ESP32): Fully operational, robust, and reliable at 9600 baud. Real-time data and command exchange confirmed.
- DHT22 Sensor: Stable temperature and humidity readings, integrated with automation logic.
- TRIAC Fan Control: Precision phase angle control (RobotDyn library), 0–100% sweep validated, zero-cross detection stable.
- Buzzer Alerts: Over-temperature and remote-triggered alerts working as intended.
- Real-time Control Stream: ESP8266 monitors
/smartfan/devices/{deviceId}/controlfor instant mode, fan speed, and temperature changes - Sub-3-second Response: Firebase updates reach ESP32 hardware within 3 seconds end-to-end
- Mode Control: Seamless switching between auto/manual modes with immediate ESP32 response
- Manual Override: Real-time fan speed control bypasses temperature logic when in manual mode
- Target Temperature: Dynamic temperature setpoint updates for automatic control mode
- Token Management: Non-realtime device token loading every 5 minutes to optimize memory usage
- New Hardware Control:
TRIACModulefor precision phase angle control (universal motor fans) - Modular C++: Clean, testable, and maintainable design
- Performance: Power sweep 0–100% validated, interrupt-driven zero-cross detection
- RobotDyn Compatible: Adapted for ESP32, modular and extensible
- WiFiManager: Captive portal for first-time setup and reconfiguration
- App WiFi Setup: Configure device WiFi via Android app
- Hardware Reset: Button for WiFi reset (hold 3s)
- Comprehensive Monitoring: Real-time voltage, current, power (W), and energy (kWh)
- Safety Alerts: Notifications for high power, overcurrent, and abnormal voltage
- Analytics: kWh tracking, historical logs, and color-coded UI
- Interactive Charts: Temperature, fan speed, and power consumption visualization with MPAndroidChart
- Time Filtering: 24-hour, 7-day, and 30-day data views with real-time chart updates
- CSV Export: Complete data export functionality with file picker integration and sharing options
- Firebase Integration: Proper ESP8266 data structure compatibility with timestamp and datetime handling
- Material Design 3: Enhanced UI with animated gauges, status chips, and responsive layouts
The SmartFan system utilizes a specialized dual-ESP architecture where two microcontrollers work together via serial communication to provide robust, fault-tolerant operation. As of October 2025, serial communication, DHT22, TRIAC, and buzzer modules are all fully functional and validated in production.
ESP8266 (WiFi & Firebase Module):
- WiFi connection management (captive portal, app-based config)
- Firebase database operations and real-time sync
- Push notifications via Firebase Cloud Messaging
- Data logging, analytics, and remote command handling
- WiFi reset (hardware button, 3s hold)
ESP32 (Sensor & Hardware Module):
- DHT22: Temperature/humidity sensor (fully working)
- ACS712: Current sensor (RMS, calibrated with voltage divider) (fully working)
- Fixed 220V for power calculations (voltage sensor removed)
- TRIAC: Fan speed control (phase angle, PWM) (fully working)
- Piezo buzzer: Alerts for over-temperature (fully working)
- Automatic/manual fan control logic
- Hardware safety monitoring and error detection
Serial Connection:
- Baud Rate: 9600 bps (confirmed stable)
- ESP8266: D6 (RX), D7 (TX) — SoftwareSerial
- ESP32: GPIO16 (RX), GPIO17 (TX) — HardwareSerial2
- Wiring: ESP8266 TX (D7) → ESP32 RX (GPIO16), ESP8266 RX (D6) → ESP32 TX (GPIO17)
- Power: Separate 3.3V/5V supplies, common ground
Message Format: <TYPE:DATA> (delimited, robust parsing, validated in production)
ESP32 → ESP8266 (Sensor Data):
<TEMP:25.5> // Temperature (°C)
<HUMID:65.0> // Humidity (%)
<VOLT:220.0> // Voltage (V) - Fixed value, voltage sensor removed
<CURR:0.8> // Current (A) - ACS712 with voltage divider (factor 2.43)
<FAN:75> // Fan speed (0-100%)
<BUZZ:ON> // Buzzer status (fully implemented and tested)
<STATUS:RUNNING> // System status
<ALL:25.5,65.0,220.0,0.8,75> // Combined data package
ESP8266 → ESP32 (Commands):
<CMD:GET_SENSORS> // Request sensor readings
<CMD:GET_STATUS> // Health check
<SET_FAN:50> // Set fan speed (manual mode)
<SET_TEMP:28.0> // Set target temperature (auto mode)
<SET_MODE:manual> // NEW: Switch to manual control mode
<SET_MODE:auto> // NEW: Switch to automatic temperature control
<FIREBASE:CONNECTED> // Firebase status update
<WIFI:CONNECTED> // WiFi status update
<BUZZ:ALERT> // Trigger buzzer alert (fully implemented)
Normal Operation Cycle:
- ESP32: Reads sensors every 2s, sends data every 5s (DHT, TRIAC, buzzer all validated)
- ESP8266: Syncs to Firebase every 5s, handles real-time control streams, sends notifications every 30s, requests data every 3s
Remote Command Flow:
- App/Firebase → ESP8266: Real-time streaming receives commands (mode, fanSpeed, targetTemperature)
- ESP8266 → ESP32: Forwards hardware commands via serial (serial comms fully working)
- ESP32: Executes, confirms, and reports (DHT, TRIAC, buzzer all working)
- ESP8266: Logs current state to Firebase for app synchronization
Real-time Control Performance:
- Firebase → ESP8266: 1-2 seconds (Firebase streaming)
- ESP8266 → ESP32: <500ms (Serial communication)
- ESP32 → Hardware: <100ms (TRIAC/sensor response)
- Total Latency: <3 seconds end-to-end
Communication Safeguards:
- Timeout detection (1s, retry logic)
- Connection health checks (ping/pong)
- Fallback: ESP32 runs autonomously if comms lost
- Error alerts: ESP8266 notifies Firebase
- All communication and error handling paths validated in production
Sensor Validation:
- Range checking, NaN filtering
- ESP32 sends error status to ESP8266
- Safe fallback values on error
- DHT, TRIAC, and buzzer error handling confirmed
Intelligent Climate Control
- Temperature-Based Control: Automatic fan speed adjustment based on DHT22 temperature readings
- TRIAC Phase Control: Precision PWM/phase angle control for universal motor fans (0-100%)
- Environmental Monitoring: DHT22 sensor for temperature and humidity tracking
- Configurable Setpoints: Remote temperature target setting via ESP8266 commands
- Audio Alerts: Piezo buzzer notifications for over-temperature conditions (+3°C threshold)
- Auto/Manual Modes: Automatic temperature control or manual fan speed override
Power Monitoring & Safety
- Electrical Monitoring: ACS712 current sensor (0.185 V/A) with voltage divider circuit and fixed 220V for power calculations
- Power Analytics: Real-time wattage calculation (V×I) and kWh energy tracking
- Safety Features: Sensor validation, range checking, and NaN detection
- RMS Calculation: True RMS measurement with calibrated sampling (100 samples)
- Error Handling: Safe fallback values and error status reporting to ESP8266
Inter-ESP Communication
- Serial Protocol: Custom message format
<TYPE:DATA>at 9600 baud - Sensor Data: Sends temperature, humidity, voltage, current, fan speed every 5 seconds
- Command Processing: Receives fan speed and temperature setpoint commands
- Health Monitoring: Connection status and communication timeout handling
- Timing Management: 2-second sensor reads, 5-second data transmission
Connectivity & Configuration
- WiFiManager Integration: User-friendly captive portal setup (192.168.4.1)
- Firebase Sync: Real-time cloud data logging and remote control
- Auto-Reconnection: Robust WiFi connection management
- Hardware Reset: Physical button WiFi reset capability (3-second hold)
- Access Point Mode: Automatic fallback for configuration
Cloud Integration & Notifications
- Firebase Database: Real-time device data updates and command handling
- Push Notifications: Firebase Cloud Messaging for mobile app alerts
- Data Logging: Historical sensor data storage and analytics
- Remote Commands: Processes fan speed and temperature commands from mobile app
- Notification Scheduling: Status updates every 30 seconds, data sync every 5 seconds
Architecture & Development
- Modular Design: Each component encapsulated in dedicated C++ classes
- Maintainable Code: Clean separation of concerns for easy extension
- Serial Debugging: Comprehensive logging for development and troubleshooting
- Non-blocking Operations: Efficient multitasking without interference
- Pin Configuration: Centralized pin management through
PinConfig.h
User Management & Security
- Firebase Authentication: Secure email/password login and registration
- Device Linking: Secure device association with user accounts
- Access Control: Firebase security rules for data protection
- Input Validation: Comprehensive validation throughout the app
- Account Management: Profile management and secure logout
Real-time Dashboard
- Animated Temperature Gauge: Beautiful SpeedView visualization with real-time updates
- Power Monitoring Cards: Live voltage, current, wattage, and energy display with color-coded status
- Fan Control Interface: Manual speed control slider and auto/manual mode toggle with immediate Firebase sync
- Status Indicators: Color-coded power consumption status chips (Low/Normal/High/Critical)
- Live Alerts: Real-time notifications for temperature and power thresholds
- Interactive Charts: Historical data visualization with MPAndroidChart library
- Time Filtering: Toggle between 24h, 7d, 30d views with smooth chart transitions
Device Management & Setup
- WiFi Configuration: Scan networks and configure device WiFi through app
- Device Setup Wizard: Step-by-step device linking and configuration
- Device Naming: Rename and organize multiple devices
- Connection Management: Monitor device connectivity and status
- Device History: Access to device configuration and setup logs
Analytics & History
- Historical Data: Interactive charts for temperature, fan speed, and power consumption trends
- Time-based Filtering: 24-hour, 7-day, and 30-day data views with chip-based selection
- CSV Export: Complete data export with file picker integration and sharing capabilities
- Chart Features: MPAndroidChart with zoom, pan, and grid lines for detailed analysis
- Enhanced Data Display: Structured historical view with ESP8266 timestamp compatibility
- Real-time Updates: Charts refresh automatically when time filter changes
- Data Validation: Robust parsing with error handling for malformed entries
User Experience & Design
- Theme Support: Light and dark mode with consistent Material Design 3
- Responsive Design: Adaptive layouts for different screen sizes
- Smooth Animations: Card animations and transition effects
- Intuitive Navigation: User-friendly interface with clear visual hierarchy
- Push Notifications: Firebase Cloud Messaging for real-time alerts
Firebase Backend Services
- Authentication: Secure user management with email/password
- Realtime Database: Live data synchronization between device and app
- Cloud Messaging: Push notifications for alerts and status updates
- Security Rules: Role-based access control and data protection
- Analytics: Usage tracking and performance monitoring
- Real-time Streaming: ESP8266 Firebase streams for instant control response
- Control Commands: Real-time mode, fan speed, and temperature updates
- Device Logging: Structured data storage with timestamp and datetime fields
Required Microcontrollers:
- ESP8266 (WiFi & Firebase)
- ESP32 (Sensors & Hardware)
Sensors & Components:
- DHT22 (GPIO4, ESP32)
- ACS712 (GPIO34, ESP32) + voltage divider circuit
- Piezo Buzzer (GPIO25, ESP32)
- TRIAC Module (GPIO18, ESP32)
- Power Supplies (separate 3.3V/5V for each ESP)
- Fixed 220V (no voltage sensor needed)
Inter-ESP Communication:
- ESP8266 D6 (RX) ↔ ESP32 GPIO17 (TX)
- ESP8266 D7 (TX) ↔ ESP32 GPIO16 (RX)
- Common ground
Additional Hardware:
- Zero Cross Detection (GPIO5, ESP32)
- WiFi Reset Button (D5, ESP8266, 3s hold)
- Voltage Range: 110V–400V AC
- Current Capacity: Up to 8A
- Protection: Overload cutoff
- Module Size: ~5.7x2.85cm
- Logic Level: 3.3V/5V compatible
Inter-ESP Communication Wiring
Step 1: Serial Communication Setup
ESP8266 (WiFi/Firebase) ESP32 (Sensors/Hardware)
┌─────────────────────┐ ┌─────────────────────┐
│ │ │ │
│ D7 (TX) ●─────────●───────●● GPIO16 (RX) │
│ D6 (RX) ●─────────●───────●● GPIO17 (TX) │
│ GND ●─────────●───────●● GND │
│ │ │ │
└─────────────────────┘ └─────────────────────┘
Step 2: Power Connections
- Each ESP board requires separate 3.3V/5V power supply
- Ensure stable power delivery and common ground reference
- Avoid power supply noise that can affect serial communication
ESP32 Sensor & Component Wiring
ESP32 Sensors & Components
┌─────────────────────┐
│ │ DHT22 Temperature/Humidity
│ GPIO4 ●──────────●────────● Data Pin
│ 3.3V ●──────────●────────● VCC
│ GND ●──────────●────────● GND
│ │
│ │ ACS712 Current Sensor (with voltage divider)
│ GPIO34 ●──────────●────────● Output → [1kΩ] ── [2kΩ] → GND
│ 5V ●──────────●────────● VCC (Voltage divider: factor 2.43)
│ GND ●──────────●────────● GND
│ │
│ │ Note: GPIO35 freed up
│ │ (Voltage sensor removed - using fixed 220V)
│ │
│ │ Piezo Buzzer
│ GPIO25 ●──────────●────────● Positive
│ GND ●──────────●────────● Negative
│ │
│ │ TRIAC Module (RobotDyn Compatible)
│ GPIO18 ●──────────●────────● PWM Input
│ GPIO5 ●──────────●────────● Zero Cross Detect
│ 5V ●──────────●────────● VCC
│ GND ●──────────●────────● GND
│ │
└─────────────────────┘
RobotDyn TRIAC Pin Configuration:
- TRIAC Output: GPIO18 (Controls TRIAC gate signal)
- Zero Cross Detection: GPIO5 (Detects AC zero-crossing events)
- Updated from GPIO12/GPIO2 for RobotDyn library compatibility
ESP8266 Connections
ESP8266 Components
┌─────────────────────┐
│ │ WiFi Reset Button
│ D5 ●──────────●────────● Button (to GND)
│ 3.3V ●──────────●────────● Pull-up resistor
│ │
│ │ Status LED (Optional)
│ D4 ●──────────●────────● LED Anode
│ GND ●──────────●────────● LED Cathode (via resistor)
│ │
└─────────────────────┘
Power Supply Requirements
ESP8266:
- Input: 5V USB or 3.3V regulated
- Current: ~200mA typical
- Notes: Can be powered via micro USB
ESP32:
- Input: 5V USB or 3.3V regulated
- Current: ~250mA typical
- Notes: Can be powered via micro USB
Sensors:
- DHT22: 3.3V, 2.5mA max
- ACS712: 5V, 13mA typical
- TRIAC Module: 5V, 20mA max
- Note: ZMPT101B voltage sensor removed
Total Power Budget:
- ESP8266 + Communication: ~200mA @ 5V
- ESP32 + Sensors: ~280mA @ 5V (reduced without voltage sensor)
- Recommended Supply: 5V @ 1A minimum
Critical Connections:
- Serial Communication: Ensure TX→RX and RX→TX crossover
- Common Ground: Both ESPs must share common ground
- Power Isolation: Consider separate power supplies for noise reduction
- TRIAC Safety: Proper isolation for AC fan control
Pull-up Resistors:
- DHT22 data line: 4.7kΩ to 3.3V
- I2C lines (if used): 4.7kΩ to 3.3V
- Reset button: 10kΩ to 3.3V
Capacitors (Recommended):
- Power supply decoupling: 100µF + 0.1µF near each ESP
Required Libraries
Install these libraries in Arduino IDE:
ESP8266 Libraries:
- Firebase ESP-Client by Mobizt
- WiFiManager by tzapu (v0.16.0+)
- ArduinoJson by Benoit Blanchon (v6.21.3+)ESP32 Libraries:
- DHT sensor library
- Firebase ESP-Client by Mobizt
- ArduinoJson by Benoit Blanchon (v6.21.3+)
- RBDdimmer (RobotDyn Dimmer Library)Installation Steps:
- Open Arduino IDE
- Go to Tools > Manage Libraries
- Search for "RBDdimmer" and install the library by RobotDyn
- Search and install each other library listed above
- Restart Arduino IDE
RobotDyn Library Installation:
- Install through Arduino IDE Library Manager
- Or download from: https://github.com/RobotDynOfficial/RBDDimmer
Firebase Credentials Setup
ESP8266 Configuration:
-
Copy Sample File:
# Navigate to ESP8266 project folder cd source/esp8266/SmartFan/ # Copy the sample credentials file cp firebase_credentials.h.sample firebase_credentials.h
-
Edit Firebase Credentials (
firebase_credentials.h):// Firebase Web API Key (from Firebase Console > Project Settings > General) #define API_KEY "your-web-api-key-here" // Firebase Realtime Database URL #define DATABASE_URL "https://your-project-id-default-rtdb.firebaseio.com/" // Service Account Authentication #define FIREBASE_PROJECT_ID "your-project-id" #define FIREBASE_CLIENT_EMAIL "firebase-adminsdk-xxxxx@your-project-id.iam.gserviceaccount.com" // Private Key (from Service Account JSON file - keep the \n characters!) #define PRIVATE_KEY "-----BEGIN PRIVATE KEY-----\n" \ "your-private-key-content-here\n" \ "-----END PRIVATE KEY-----\n" // WiFi Configuration (optional - can be set via WiFiManager) #define WIFI_SSID "your-wifi-network-name" #define WIFI_PASSWORD "your-wifi-password" // Device Configuration #define DEVICE_ID "SmartFan_ESP8266_001"
Getting Firebase Credentials:
- Go to Firebase Console
- Select your project (or create a new one)
- For Web API Key: Go to Project Settings > General
- For Service Account:
- Go to Project Settings > Service Accounts
- Click "Generate new private key"
- Download JSON file and extract required information
Android Google Services Setup
-
Copy Sample File:
cd source/android/SmartFan/app/ cp google-services.json.sample google-services.json -
Replace with Actual File:
- Go to Firebase Console > Project Settings > General
- Add your Android app if not already added
- Download the
google-services.jsonfile for your Android app - Replace the sample file with the downloaded file
-
Verify Package Name:
- Ensure the package name in
google-services.jsonmatchescom.qppd.smartfan - Or update the package name in your Firebase project
- Ensure the package name in
Security Notes
Important Security Guidelines:
- Never commit actual credential files (
firebase_credentials.handgoogle-services.json) to version control - These files are already included in
.gitignoreto prevent accidental commits - Use environment variables for production deployments
- Rotate Firebase keys regularly for enhanced security
- Set up Firebase Security Rules to protect your database
Firebase Security Rules Example:
{
"rules": {
"users": {
"$uid": {
".read": "$uid === auth.uid",
".write": "$uid === auth.uid"
}
},
"devices": {
"$deviceId": {
".read": "auth != null && root.child('devices').child($deviceId).child('owner').val() === auth.uid",
".write": "auth != null && root.child('devices').child($deviceId).child('owner').val() === auth.uid"
}
}
}
}Dual-ESP Firmware Configuration
-
Clone Repository:
git clone https://github.com/qppd/IoT-Smart-Fan.git cd IoT-Smart-Fan -
Configure ESP8266 (WiFi Manager):
- Edit
source/esp8266/SmartFan/firebase_credentials.hwith your Firebase credentials - Set your Firebase project credentials
- Configure default WiFi fallback credentials (optional)
- Edit
-
Upload ESP8266 Firmware:
- Connect ESP8266 to computer
- Select "NodeMCU 1.0 (ESP-12E Module)" board in Arduino IDE
- Upload
source/esp8266/SmartFan/SmartFan.ino
-
Upload ESP32 Firmware:
- Connect ESP32 to computer
- Select "ESP32 Dev Module" board in Arduino IDE
- Upload
source/esp32/SmartFan/SmartFan.ino
-
Power On & Test:
- Power both ESP boards simultaneously
- Monitor serial outputs for initialization messages
- Verify communication test passes on both boards
Build Configuration
-
Open Project:
# Open in Android Studio source/android/SmartFan/ -
Firebase Setup:
- Download
google-services.jsonfrom Firebase Console - Place in
app/directory - Ensure package name matches your Firebase project
- Download
-
Build & Install:
- Build project in Android Studio
- Install on Android device (API 21+)
- Grant required permissions
WiFiManager Configuration Process
-
Access Point Mode:
- ESP8266 creates network:
SmartFan_Setup - No password required (open network)
- Captive portal automatically opens
- ESP8266 creates network:
-
Network Configuration:
- Connect device to ESP8266 network
- Navigate to:
192.168.4.1 - Enter WiFi credentials and device settings
- ESP8266 saves configuration and connects
-
Reset Capability:
- Hold WiFi reset button (GPIO0) for 3 seconds
- ESP8266 clears stored credentials
- Returns to access point mode for reconfiguration
-
Connection Confirmation:
- ESP8266 connects to configured WiFi
- Firebase connection established
- ESP32 communication test initiated
- System ready for operation
App-Based Configuration
-
Network Scanning:
- App scans for available WiFi networks
- Automatically detects SmartFan access points
- Material Design interface for network selection
-
Configuration Transfer:
- Select target WiFi network
- Enter credentials and optional device ID
- App connects to SmartFan AP and transfers config
-
Completion:
- ESP32 receives configuration
- Automatically connects to home WiFi
- Ready for device linking in app
ESP8266 Control Stream Testing
Test Real-time Mode Changes:
-
Update Firebase database:
// Path: /smartfan/devices/SmartFan_ESP8266_001/control/mode "manual"
-
Expected ESP8266 serial output:
Control Stream Update Received! Path: /mode Value: "manual" Mode changed from 'auto' to 'manual' Sent mode change to ESP32: manual -
Expected ESP32 to receive:
<SET_MODE:manual>
Test Real-time Fan Speed Changes:
-
Update Firebase database:
// Path: /smartfan/devices/SmartFan_ESP8266_001/control/fanSpeed 75
-
Expected ESP8266 output:
Control Stream Update Received! Path: /fanSpeed Value: 75 Fan speed changed from 50 to 75 Sent fan speed change to ESP32: 75 -
Expected ESP32 to receive:
<SET_FAN:75>
Performance Validation:
- Firebase → ESP8266: < 2 seconds
- ESP8266 → ESP32: < 500ms
- Total latency: < 3 seconds end-to-end
ESP32 Hardware Controller Testing
Serial Command Testing:
// Test temperature control logic
TEST TEMP
TEST TRIAC
TEST ALL
// Manual temperature setting
TEMP 32.0
// Status check
STATUSExpected ESP32 Temperature Control:
- ≥32°C: 99% fan speed
- 30-31°C: 90% fan speed
- 28-29°C: 80% fan speed
- 26-27°C: 60% fan speed
- 24-25°C: 40% fan speed
- <24°C: 20% fan speed
TRIAC Module Testing:
// RobotDyn TRIAC control validation
testTRIACDimmer();
// Tests power levels: 0%, 25%, 50%, 75%, 100%
// Verifies GPIO18 (PWM) and GPIO5 (zero-cross) functionalityCurrent Sensor Calibration:
- Voltage Divider Factor: 2.43 (compensates for signal attenuation)
- ACS712 Sensitivity: 0.185 V/A
- Calibration: Multimeter validation (0.074A reading vs 0.18A actual)
ESP8266 Communication Testing
Communication Health Check:
// ESP8266 → ESP32 ping/pong testing
testESP8266Communication();
// Expected output:
Testing ESP8266 <-> ESP32 communication...
Sent to ESP32: <TEST:ESP8266_PING>
Received from ESP32: <TEST:ESP32_PONG>
Communication test PASSED!Memory Monitoring:
// ESP8266 memory diagnostics
Initial Free Heap: ~45000 bytes
After WiFi: ~35000 bytes
After Firebase: ~28000 bytes
Warning threshold: <8000 bytesStream Recovery Testing:
- Disconnect internet temporarily
- Expected recovery logs:
Control Stream Error: connection timeout Control stream timed out, attempting to resume... - Reconnect internet - automatic stream reinitialization
Chart & Export Functionality
Interactive Charts Testing:
- Temperature Chart: Line chart with orange fill, zoom/pan enabled
- Fan Speed Chart: Bar chart with blue bars, 0-100% range
- Power Chart: Green line on right Y-axis, overlaid with temperature
- Time Filtering: Test 24h, 7d, 30d chip selection
CSV Export Testing:
- Tap export button → File picker opens
- Select save location → CSV file created
- Verify format:
Timestamp,DateTime,Temperature(°C),Fan Speed(%),Voltage(V),Current(A),Power(W),Energy(kWh) 1727087543,"2024-09-23 15:45:43",28.5,75,220.1,0.156,34.34,0.045
Data Compatibility:
- ESP8266 Structure: Supports timestamp + datetime fields
- Time Display: Uses datetime field first, falls back to timestamp
- Timezone: GMT+8 as configured in ESP8266
ESP-to-ESP Communication Problems
No Communication Between ESP8266 and ESP32:
- Check Wiring: Verify TX↔RX, RX↔TX connections and common ground
- ESP8266 D7 (TX) → ESP32 GPIO16 (RX)
- ESP8266 D6 (RX) → ESP32 GPIO17 (TX)
- Connect GND pins of both boards
- Verify Baud Rate: Ensure both boards use 9600 baud (now confirmed stable)
- Power Supply: Check stable power to both ESP boards
- Serial Monitor: Review error messages in both ESP serial outputs
Message Timeouts or Corrupted Data:
- Check for loose connections or electromagnetic interference
- Verify message format compliance:
<TYPE:DATA>(now validated in production) - Monitor for buffer overflow or memory issues
- Ensure proper message delimiter parsing
If all above are correct and issues persist, check for firmware updates. As of October 2025, serial comms, DHT, TRIAC, and buzzer are all confirmed working.
Sensor Reading Issues
ESP32 Sensors Not Reading:
- DHT22: Verify 3.3V/5V power and data pin (GPIO4) connection
- ACS712: Check analog pin (GPIO34), voltage divider circuit, and ensure correct sensitivity (0.185V/A)
- Power Supply: Ensure stable power to all sensor modules
- Wiring: Check for short circuits or loose connections
- Note: Voltage sensor removed - using fixed 220V value
Invalid Sensor Values (NaN):
- DHT22 initialization timeout - check power and data line
- Current sensor returning out-of-range values
- Review sensor validation logic in ESP32 code
WiFi & Firebase Connectivity
ESP8266 WiFi Connection Failed:
- Captive Portal: Connect to "SmartFan_Setup" AP and configure at 192.168.4.1
- WiFi Reset: Hold WiFi reset button for 3 seconds to clear stored credentials
- Signal Strength: Ensure strong WiFi signal in installation location
- Router Compatibility: Check 2.4GHz WiFi support (ESP8266 limitation)
Firebase Not Updating:
- Internet Connectivity: Verify ESP8266 can reach internet
- Firebase Credentials: Check
firebase_credentials.hconfiguration - Authentication: Verify Firebase security rules and project settings
- Database Structure: Ensure proper Firebase database schema
- Real-time Streams: Check if control stream is active and receiving updates
- Memory Issues: Monitor ESP8266 heap - warning below 8KB free memory
Firebase Streaming Issues:
- Stream Initialization Failed: Check Firebase database rules for read access to
/smartfan/devices/{deviceId}/control - Stream Timeout: ESP8266 automatically attempts reconnection - monitor serial output for recovery messages
- Command Not Reaching ESP32: Verify ESP8266 → ESP32 serial communication with ping/pong test
- Mode Changes Not Applied: Check that ESP32 properly processes
<SET_MODE:auto/manual>commands
NTP Time Sync Issues (ESP8266):
-
Problem: NTP shows success but time is 1970
- Cause: ESP8266 not receiving valid time data from NTP servers
- Check Router/Firewall: Ensure UDP port 123 (NTP) is not blocked
- Check ISP Blocking: Some ISPs block NTP traffic
- Try Mobile Hotspot: Test with phone's mobile data
-
DNS Server Issues:
- Change DNS servers in router to Google DNS (8.8.8.8, 8.8.4.4) or Cloudflare (1.1.1.1, 1.0.0.1)
- Add manual DNS to ESP8266 code:
WiFi.config(ip, gateway, subnet, dns1, dns2);
-
Network Connectivity Tests:
# Test NTP accessibility (Windows PowerShell) Test-NetConnection -ComputerName pool.ntp.org -Port 123 # Check DNS resolution ping pool.ntp.org ping time.google.com
-
Router Configuration:
- Restart router
- Check if MAC address filtering is enabled
- Verify router firmware is up to date
- Ensure NTP is enabled on router (some routers block NTP for security)
Code Improvements for NTP Issues:
- Enhanced NTP setup with multiple server testing
- Longer timeout periods for slow connections
- Better error detection and fallback time setting
- Improved diagnostics with DNS verification before NTP attempts
RobotDyn TRIAC Integration Issues
TRIAC Not Responding:
-
Library Installation: Ensure RBDdimmer library is properly installed
# Install via Arduino IDE Library Manager # Search: "RBDdimmer" # Or download: https://github.com/RobotDynOfficial/RBDDimmer
-
Pin Configuration Update: Verify GPIO pins match RobotDyn requirements
- TRIAC Output: GPIO18 (updated from GPIO12)
- Zero Cross Detection: GPIO5 (updated from GPIO2)
-
Wiring Verification:
- Check TRIAC module connections to ESP32
- Verify zero-cross detection circuit is functioning
- Ensure proper AC phase detection wiring
-
Testing and Calibration:
// Uncomment in setup() to test TRIAC functionality testTRIACDimmer(); // Tests power levels: 0%, 25%, 50%, 75%, 100% // Each level held for 2 seconds // Monitor serial output for power readings
-
ESP32 Serial Commands for Testing:
// Send via Serial Monitor to ESP32 TEST TRIAC // Test TRIAC control logic TEST TEMP // Test temperature control logic TEST ALL // Run comprehensive tests TEMP 32.0 // Set test temperature STATUS // Show current system status
Common RobotDyn Issues:
- No dimming response: Check zero-cross pin connection (GPIO5)
- Erratic behavior: Verify AC phase detection wiring
- Library errors: Ensure RBDdimmer library compatibility
- Power level mismatch: Library may adjust values internally
- TRIAC not responding to commands: Verify ESP32 receives
<SET_FAN:XX>commands from ESP8266
Comprehensive Testing Results Expected:
- Temperature Control: 99% at ≥32°C, 90% at 30-31°C, 80% at 28-29°C, etc.
- TRIAC Response: Actual power matches target speed within ±5%
- Mode Switching: Auto/manual transitions work without fan interruption
Safety Considerations:
- Always use proper AC isolation when working with mains voltage
- Test with low-voltage AC sources first
- The TRIAC module should include optical isolation
- Never work on live AC circuits without proper safety equipment
Fan Control & Hardware Issues
Fan Not Responding:
- TRIAC Wiring: Check TRIAC module connections and zero-cross detection (GPIO5, updated from GPIO2)
- AC Power: Verify proper AC wiring and safety isolation
- Control Signal: Monitor ESP32 PWM output (GPIO18, updated from GPIO12) with oscilloscope
- Load Testing: Test TRIAC module with resistive load first
RobotDyn TRIAC Module Issues:
- Hardware Requirements: RobotDyn AC Dimmer Module + ESP32
- Zero-cross detection: Usually included with RobotDyn module
- Pin Compatibility: ESP32 GPIO18/GPIO5 based on RobotDyn library chart
Excessive Power Consumption:
- Check current sensor calibration, voltage divider factor (2.43), and scaling factors (ACS712: 0.185V/A)
- Verify TRIAC switching timing and zero-cross synchronization
- Monitor for partial switching or continuous AC conduction
- Note: Using fixed 220V value for power calculations (voltage sensor removed)
ESP8266 Monitor Output:
=== Smart Fan ESP8266 - Firebase & WiFi Manager ===
WiFi connected: MyNetwork (IP: 192.168.1.105)
Firebase connected successfully
Received from ESP32: <ALL:25.5,65.0,220.0,0.8,75>
Firebase data sent successfully
Notification sent: Temperature: 25.5°C, Fan: 75%
ESP32 Monitor Output:
=== Smart Fan ESP32 - Sensor & Hardware Controller ===
Temperature: 25.5°C, Humidity: 65.0%
Voltage: 220.0V, Current: 0.800A, Power: 176.00W
Fan Speed: 75% (Target: 80°C)
Sent to ESP8266: <ALL:25.5,65.0,220.0,0.8,75>
Health Check Commands:
- ESP8266 → ESP32:
<CMD:GET_STATUS>(every 15 seconds) - ESP32 → ESP8266:
<STATUS:RUNNING>(response confirmation)
Connection Status Indicators:
- Healthy: Regular data exchange, no timeouts
- Warning: Occasional timeouts, retry attempts
- Failed: No communication for >30 seconds
Monitoring Tips:
- Timing Analysis: Monitor message intervals and response times
- Error Logging: Track failed message attempts and timeout events
- Data Validation: Verify sensor data ranges and format compliance
- Performance Metrics: Monitor Firebase sync frequency and success rates
graph TB
subgraph "ESP32 Hardware Controller"
A[ESP32] --> B[DHT22 Sensor<br/>GPIO4]
A --> C[ACS712 Current<br/>GPIO34 + Voltage Divider]
A --> E[TRIAC Module<br/>GPIO18/GPIO5]
A --> F[Piezo Buzzer<br/>GPIO25]
A --> G[Serial Comm<br/>GPIO16/GPIO17]
end
subgraph "ESP8266 WiFi Manager"
H[ESP8266] --> I[WiFi Manager]
H --> J[Firebase Client]
H --> K[Serial Comm<br/>D6/D7]
H --> L[WiFi Reset<br/>D3]
end
subgraph "Cloud Services"
M[Firebase Auth]
N[Realtime Database]
O[Cloud Messaging]
P[Security Rules]
end
subgraph "Mobile App"
Q[Android App]
R[Material Design UI]
S[Device Management]
T[Real-time Monitoring]
end
subgraph "Hardware"
U[AC Fan Motor]
V[Zero Cross Detection]
W[TRIAC Control Circuit]
end
G -.->|9600 baud| K
E --> V
E --> W
W --> U
J --> M
J --> N
J --> O
J --> P
Q --> M
Q --> N
Q --> O
style A fill:#1976D2,stroke:#fff,stroke-width:2px,color:#fff
style H fill:#FF5722,stroke:#fff,stroke-width:2px,color:#fff
style U fill:#4CAF50,stroke:#fff,stroke-width:2px,color:#fff
Key Architecture Updates (October 2025):
- Voltage Sensor Removed: GPIO35 freed up, using fixed 220V value
- RobotDyn TRIAC Integration: GPIO18/GPIO5 (updated from GPIO12/GPIO2)
- Serial Communication Validated: 9600 baud confirmed stable in production
- All Core Modules Working: DHT22, TRIAC, buzzer, and ESP communication operational
Firebase Realtime Database Schema
{
"users": {
"uid123": {
"email": "user@email.com",
"devices": {
"deviceIdABC": true
},
"settings": {
"theme": "dark",
"tempMin": 25,
"tempMax": 30
},
"fcmToken": "firebase_messaging_token"
}
},
"devices": {
"deviceIdABC": {
"owner": "uid123",
"name": "Living Room Fan",
"current": {
"temperature": 28.5,
"humidity": 65.0,
"fanSpeed": 2,
"mode": "auto",
"voltage": 220.1,
"current": 0.150,
"watt": 33.02,
"kwh": 0.125,
"lastUpdate": 1692620000
},
"logs": {
"timestamp_1692620000": {
"timestamp": 1692620000,
"temperature": 28.5,
"fanSpeed": 2,
"voltage": 220.1,
"current": 0.150,
"watt": 33.02,
"kwh": 0.125
}
}
}
}
}Directory Organization
SmartFan/
├── diagram/ # Circuit diagrams and schematics
│ ├── SmartFan.fzz # Fritzing project file
│ └── SmartFan.png # Circuit diagram image
├── model/ # 3D printed enclosures
│ ├── *.stl # STL files for 3D printing
│ ├── *.gcode # Pre-sliced G-code files
│ └── *.png # Component images
├── README.md # Main project documentation
└── source/
├── ESP_Communication_Test_Guide.txt
├── android/SmartFan/ # Android application
│ ├── app/
│ │ ├── src/main/java/com/qppd/smartfan/
│ │ │ ├── auth/ # Authentication activities
│ │ │ ├── device/ # Device management & WiFi setup
│ │ │ ├── MainActivity.java # Main dashboard activity
│ │ │ ├── SettingsActivity.java
│ │ │ ├── HistoryActivity.java
│ │ │ └── MyFirebaseMessagingService.java
│ │ ├── src/main/res/ # Resources (layouts, drawables, values)
│ │ ├── google-services.json.sample
│ │ └── google-services.json # Add your Firebase config
│ ├── build.gradle
│ └── settings.gradle
├── esp32/SmartFan/ # ESP32 firmware (Hardware Controller)
│ ├── SmartFan.ino # Main application logic
│ ├── DHTSensor.cpp/.h # DHT22 temperature/humidity sensor
│ ├── CURRENTSensor.cpp/.h # ACS712 current measurement with voltage divider
│ ├── TRIACModule.cpp/.h # RobotDyn TRIAC control (GPIO18/GPIO5)
│ ├── BUZZERConfig.cpp/.h # Piezo buzzer alerts
│ ├── ESPCommunication.cpp/.h # Serial communication with ESP8266
│ └── PinConfig.h # Pin assignments (updated pins)
└── esp8266/SmartFan/ # ESP8266 firmware (WiFi & Firebase)
├── SmartFan.ino # Main application logic
├── FirebaseConfig.cpp/.h # Firebase integration & cloud messaging
├── WiFiManager.cpp/.h # WiFi management & captive portal
├── NTPConfig.cpp/.h # Network time protocol
├── ESPCommunication.cpp/.h # Serial communication with ESP32
├── PinConfig.h # Pin assignments
├── firebase_credentials.h.sample
└── firebase_credentials.h # Add your Firebase credentials
Notes:
- Voltage sensor (ZMPT101B) removed - using fixed 220V value
- RobotDyn TRIAC library integration complete
- All ESP32 GPIO pins updated for RobotDyn compatibility
Temperature-Based Fan Control
Automatic Fan Speed Logic (as of October 2025): The ESP32 now uses absolute temperature thresholds for fan speed control, not temperature difference from target. The logic is:
// ESP32 SmartFan.ino (auto mode)
if (currentTemp >= 32.0) {
fanSpeed = 99; // 99% speed (≥32°C)
} else if (currentTemp >= 30.0) {
fanSpeed = 90; // 90% speed (30–31.99°C)
} else if (currentTemp >= 28.0) {
fanSpeed = 80; // 80% speed (28–29.99°C)
} else if (currentTemp >= 26.0) {
fanSpeed = 70; // 70% speed (26–27.99°C)
} else if (currentTemp >= 24.0) {
fanSpeed = 60; // 60% speed (24–25.99°C)
} else if (currentTemp >= 22.0) {
fanSpeed = 50; // 50% speed (22–23.99°C)
} else {
fanSpeed = 0; // OFF (<22°C)
}Thresholds:
- ≥32°C: 99% fan speed
- 30–31.99°C: 90% fan speed
- 28–29.99°C: 80% fan speed
- 26–27.99°C: 70% fan speed
- 24–25.99°C: 60% fan speed
- 22–23.99°C: 50% fan speed
- <22°C: OFF (0%)
Note: This replaces the previous tempDiff-based logic. The README and codebase are now consistent as of October 2025.
Power Monitoring Calibration
Current Sensor (ACS712):
// In CURRENTSensor.cpp
#define ACS_SENSITIVITY 0.185 // 5A module: 185mV/A
#define ACS_OFFSET 2.5 // Zero current voltage
#define VOLTAGE_DIVIDER 2.43 // Voltage divider factor (1kΩ + 2kΩ circuit)Voltage Configuration:
// Fixed voltage value in ESP32 SmartFan.ino
sensors.voltage = 220.0; // No sensor neededTheme Configuration
Color Schemes:
<!-- In colors.xml -->
<color name="primary">#1976D2</color>
<color name="accent">#FF5722</color>
<color name="temperature_normal">#4CAF50</color>
<color name="temperature_high">#FF9800</color>
<color name="temperature_critical">#F44336</color>Material Design 3 Components:
- Dynamic color theming support
- Adaptive layouts for different screen sizes
- Consistent typography and spacing
Alert Thresholds
| Status | Power Range | Color | Action |
|---|---|---|---|
| Low | < 10W | Green | Normal operation |
| Normal | 10-50W | Blue | Standard monitoring |
| High | 50-100W | Yellow | Caution alert |
| Critical | ≥ 100W | Red | Immediate notification |
Temperature Alerts
- Over-temperature: Buzzer activation at setpoint + 2°C
- Push Notifications: Real-time alerts via Firebase FCM
- Alert Duration: 300ms buzzer beep (configurable)
- Reset Conditions: Automatic reset when temperature normalizes
Component Validation
Sensor Testing:
# Serial Monitor Output
Temperature: 26.5°C | Humidity: 60%
Voltage: 220.1V | Current: 0.150A
Power: 33.02W | Energy: 0.125kWh
Fan Speed: 65% | Mode: AUTOTRIAC Testing:
- Power sweep validation (0-100%)
- Zero-cross detection timing
- Phase angle accuracy verification
Test Cases
- Authentication Flow: Login/register/logout validation
- Device Linking: QR code and manual ID entry testing
- Real-time Updates: Live data synchronization validation
- WiFi Configuration: Captive portal and app-based setup
- Power Monitoring: Threshold alerts and display accuracy
- Theme Switching: Light/dark mode consistency
- Offline Handling: Graceful degradation without connectivity
Access Control Rules
{
"rules": {
"users": {
"$uid": {
".read": "$uid === auth.uid",
".write": "$uid === auth.uid"
}
},
"devices": {
"$deviceId": {
".read": "root.child('devices').child($deviceId).child('owner').val() === auth.uid",
".write": "root.child('devices').child($deviceId).child('owner').val() === auth.uid"
}
}
}
}Security Features
- WPA2 Protection: SmartFan AP uses secure password
- Timeout Protection: Configuration portal auto-closes after inactivity
- Reset Protection: Physical button required for WiFi reset
- Limited Access: Configuration only available in setup mode
Next Version Roadmap
Smart Features:
- Machine learning temperature prediction
- Advanced analytics and usage patterns
- Weather integration for predictive control
- Scheduling and automation rules
App Enhancements:
- Interactive charts and data visualization
- Customizable notification preferences
- Multi-room and multi-device management
- Geofencing for automatic control
Hardware Improvements:
- Bluetooth fallback configuration
- Battery backup for settings retention
- Mesh networking for multiple devices
- Additional sensor types support
We welcome contributions from the community! Here's how you can help:
Setup Instructions
-
Fork and Clone:
git clone https://github.com/your-username/IoT-Smart-Fan.git cd IoT-Smart-Fan -
Create Feature Branch:
git checkout -b feature/your-feature-name
-
Development Environment:
- ESP32: Arduino IDE or PlatformIO
- Android: Android Studio (latest version)
- Firebase: Firebase Console access
-
Testing:
- Test hardware changes with actual components
- Validate app changes on multiple devices
- Ensure backward compatibility
- Bug Reports: Use issue templates with detailed descriptions
- Feature Requests: Discuss new features in issues before implementing
- Documentation: Update README and code comments
- Testing: Include tests for new functionality
- Code Style: Follow existing conventions and formatting
Android App: Apache 2.0 License
ESP32 Firmware: MIT License
See the LICENSE file for complete details.
