Power System Monitoring and Safety Device - README

Overview

This is a Smart Energy Monitoring and Safety System designed for residential areas in Nigeria. The system monitors power parameters (Voltage, Current, Power), displays data locally on an OLED screen, transmits data to the cloud via Blynk, and includes automatic safety protection that disconnects power during fault conditions.

This project was professionally designed and implemented as a Final Year Project (FYP) for a client, focusing on robust industrial-grade monitoring principles and cloud-integrated data analytics.

Features

✅ Real-time Monitoring: Continuous voltage, current, and power measurement
✅ Cloud Dashboard: Blynk IoT integration for remote monitoring
✅ Cloud Logging: Automatic logging to Google Sheets for historical data analysis
✅ Local Display: 1.3" OLED screen showing live data
✅ Safety Protection: Automatic relay trip on over-voltage, under-voltage, or over-current
✅ Offline Operation: Continues monitoring and protection even without WiFi
✅ Battery Monitoring: Track system uptime and battery health via heartbeat logging
✅ Visual Status: RGB LED indicates system state
✅ Modular Architecture: Clean C++ design with separated concerns
✅ Non-blocking: Uses millis() timers, no delay() calls

Hardware Components

• Microcontroller: ESP32 Dev Kit
• Voltage Sensor: ZMPT101b (simulated with potentiometer for testing)
• Current Sensor: SCT-013 100A CT (simulated with potentiometer for testing)
• Relay: 1-Channel Relay Module
• Display: 1.3" OLED (SSD1306, I2C)
• Status LED: RGB LED (Common Cathode)
• Power Control: Physical Boat Switch (hardware power on/off)
• Power: AC-DC 5V with 7.4V battery backup

Pin Configuration

Component	GPIO Pin	Notes
Voltage Sensor	GPIO 34	ADC1_CH6
Current Sensor	GPIO 35	ADC1_CH7
Relay	GPIO 26	Configurable Active HIGH/LOW
RGB LED (Red)	GPIO 25	PWM capable
RGB LED (Green)	GPIO 33	PWM capable
RGB LED (Blue)	GPIO 32	PWM capable
OLED SDA	GPIO 21	I2C Data
OLED SCL	GPIO 22	I2C Clock

Software Architecture

Modules

1. EnergySensor: Handles sensor reading with calibration
2. DisplayManager: Manages OLED display screens
3. NetworkManager: WiFi and Blynk communication
4. SafetyManager: Threshold monitoring and relay control
5. CloudLogger: Automatic logging to Google Sheets
6. PerformanceLogger: CSV logging via Serial and cloud integration
7. StateManager: Finite state machine coordinating all modules

State Machine

• STATE_BOOT: Initialization and WiFi connection
• STATE_NORMAL: Active monitoring with cloud logging
• STATE_TRIP_PROTECTION: Fault detected, power disconnected
• STATE_OFFLINE_MODE: WiFi lost, local monitoring continues

Getting Started

1. Try in Wokwi Simulator (No Hardware Required!)

You can test the entire system in your browser using Wokwi:

1. Install Wokwi for VS Code
2. Build the project: pio run
3. Press F1 → "Wokwi: Start Simulator"
4. Adjust potentiometers to simulate voltage/current changes

See WOKWI_SIMULATION.md for detailed testing scenarios.

2. Install PlatformIO

Install PlatformIO IDE or CLI.

3. Configure Credentials

IMPORTANT: Create your secrets.h file by moving the template from the docs folder:

# Move the template to the include folder and rename it
copy docs/secrets.h.example include/secrets.h  # On Windows
# OR
cp docs/secrets.h.example include/secrets.h    # On Linux/Mac

Edit include/secrets.h and update your credentials:

// WiFi Credentials
#define SECRET_WIFI_SSID      "Your_WiFi_Name"
#define SECRET_WIFI_PASSWORD  "Your_WiFi_Password"

// Blynk IoT Credentials  
#define SECRET_BLYNK_TEMPLATE_ID     "Your_Template_ID"
#define SECRET_BLYNK_TEMPLATE_NAME   "Your_Template_Name"
#define SECRET_BLYNK_AUTH_TOKEN      "Your_Blynk_Token"

// Google Sheets Logging
#define SECRET_GOOGLE_SHEETS_URL     "https://script.google.com/macros/s/YOUR_DEPLOYMENT_ID/exec"

Note: secrets.h is already in .gitignore and will NOT be committed to version control.

4. Configure Safety Thresholds

Adjust thresholds in include/config.h:

#define VOLTAGE_MAX           240.0  // Over-voltage trip
#define VOLTAGE_MIN           180.0  // Under-voltage trip
#define CURRENT_MAX           20.0   // Over-current trip

5. Build and Upload

pio run --target upload
pio device monitor

Blynk Setup

Click here for the detailed Step-by-Step Blynk Setup Guide

Virtual Pins

• V0: Voltage (read-only)
• V1: Current (read-only)
• V2: Power (read-only)
• V3: System State (read-only)
• V4: Reset Button (write)

Datastreams

Create the following datastreams in your Blynk template:

1. V0 - Voltage (0-300V)
2. V1 - Current (0-100A)
3. V2 - Power (0-10000W)
4. V3 - State (String)
5. V4 - Reset (Integer 0-1)

Cloud Logging (Google Sheets)

The system automatically logs performance data and system events to Google Sheets when WiFi is connected.

Setup Google Apps Script

1. Create a Google Sheet named "ESP32 Performance Logs"
2. Create 4 tabs: SystemEvents, Latency, Accuracy, TripResponse
3. Open Script Editor: Extensions → Apps Script
4. Paste the script from docs/google_apps_script.js
5. Deploy as Web App:
   • Click Deploy → New deployment
   • Type: Web app
   • Execute as: Me
   • Who has access: Anyone
   • Click Deploy
   • Copy the deployment URL

Configure in ESP32

Edit include/config.h:

#define GOOGLE_SHEETS_URL "https://script.google.com/macros/s/YOUR_DEPLOYMENT_URL/exec"
#define ENABLE_CLOUD_LOGGING      // Enables automatic cloud logging
#define ENABLE_PERFORMANCE_LOGGING // Enables performance metrics

What Gets Logged

SystemEvents Tab:

• BOOT - System startup
• HEARTBEAT - Every 5 minutes (includes WiFi RSSI for battery health monitoring)
• POWER_OUTAGE - Mains voltage lost
• POWER_RESTORED - Mains voltage restored
• TRIP - Safety faults with fault reason

Latency Tab:

• Sensor read time
• Blynk transmit time
• Total latency (logged on every Blynk transmission)

Accuracy Tab:

• Voltage, Current, Power readings
• Logged every 10 seconds

TripResponse Tab:

• Fault detection time
• Relay trip time
• Total response time (logged when safety trips occur)

Battery Health Monitoring

Use heartbeat data to monitor battery health:

• Continuous heartbeats during outage = Healthy battery
• Gaps in heartbeats = Battery depleted or WiFi too weak
• Declining RSSI = Battery voltage dropping
• BOOT after gap = System shut down (battery dead)

Calibration

After hardware assembly, calibrate sensors:

1. Connect a known voltage source (measure with multimeter)
2. Adjust VOLTAGE_SLOPE and VOLTAGE_INTERCEPT in config.h
3. Connect a known current load (measure with clamp meter)
4. Adjust CURRENT_SLOPE and CURRENT_INTERCEPT in config.h
5. Verify accuracy across operating range

Safety Features

Automatic Protection

The system continuously monitors power parameters every 100ms. If any threshold is exceeded:

1. Relay trips immediately (power disconnected)
2. RGB LED turns RED
3. OLED displays fault reason
4. Alert sent to Blynk (if connected)

Reset Procedure

To reset after a trip:

1. Ensure fault condition is cleared
2. Press reset button in Blynk app

The system will only reset if readings are within safe limits.

Offline Safety

Critical: Safety monitoring continues even when WiFi is disconnected. The relay will trip on fault conditions regardless of network status.

RGB LED Status

• 🔵 Blue: Booting/Initializing
• 🟢 Green: Normal operation
• 🟡 Yellow: Offline mode (WiFi disconnected)
• 🔴 Red: Trip protection active

Troubleshooting

Display Not Working

• Check I2C address (0x3C or 0x3D)
• Verify SDA/SCL connections
• Check serial monitor for initialization errors

WiFi Not Connecting

• Verify credentials in config.h
• Check 2.4GHz WiFi (ESP32 doesn't support 5GHz)
• Monitor serial output for connection attempts

Blynk Not Connecting

• Verify auth token
• Ensure WiFi is connected first
• Check Blynk server status

False Trips

• Adjust hysteresis values in config.h
• Calibrate sensors properly
• Check for electrical noise

Migration to Production

To switch from simulation (potentiometers) to real sensors:

1. Remove -D SIMULATION_MODE from platformio.ini
2. Add EmonLib library
3. Update EnergySensor.cpp with EmonLib code
4. Recalibrate with actual sensors

Documentation

📚 Complete Documentation Suite

• API Documentation - Complete API reference, configuration guide, calibration procedures, and troubleshooting
• Technical Challenges Report - Detailed analysis of all challenges faced and solutions implemented
• Chapter 3: Methodology - Academic methodology documentation with diagrams and algorithms
• Blynk Setup Guide - Step-by-step IoT platform configuration
• Hybrid Analysis Guide - Guide for combining cloud and USB data for unified analysis
• Wokwi Simulation Guide - Browser-based testing without hardware

Quick Links

Topic	Document	Description
Getting Started	API Documentation	Installation and first-time setup
API Reference	API Documentation	Complete class and method documentation
Calibration	API Documentation	Sensor calibration step-by-step
Troubleshooting	API Documentation	Common issues and solutions
Contributing	API Documentation	Code style and contribution guidelines
Future Plans	API Documentation	Roadmap and planned features

License

MIT License - Free for educational and commercial use

Support

For issues or questions, please open an issue on GitHub.

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⚠️ Safety Warning: This system controls mains power. Only qualified electricians should install and wire the hardware. Improper installation can result in electric shock, fire, or death.