IoT-Based Flood Detection System with Blynk

Updated: Removing OLED Functionalities

Video Demo

Watch it on TikTok: Video Demonstration

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Project Overview

This is an IoT-based flood detection system using ESP8266, HC-SR04 ultrasonic sensor, and the Blynk IoT platform.

Features:

• Distance monitoring in cm & inches
• LED indicators for water level thresholds
• Buzzer alarm for high water levels
• Optional cloud logging via Blynk.logEvent("high_water_levels")

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Disclaimer

This project is intended for educational and prototyping purposes only. It should not be relied upon as a primary flood warning system for life safety or property protection.

Always use certified and government-approved flood detection/alert systems in real-world applications.

The Author are not responsible for any damage, loss, or injury that may result from the use of this project.

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Hardware Components

Component	Description
ESP8266 NodeMCU	Main Wi-Fi microcontroller
HC-SR04 Ultrasonic Sensor	Measures water level
Buzzer	Audible alert
Red, Blue, Green LEDs	Visual alerts for water levels
Yellow LED	Blynk connection indicator
220Ω Resistors (x3)	LED current-limiting
Jumper Wires	Connections
Breadboard	Prototyping

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Circuit Diagram

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Pin Connections

Component	Pin Label	ESP8266 GPIO	NodeMCU Pin
Ultrasonic	Trig	GPIO12	D6
	Echo	GPIO14	D5
Buzzer	+	GPIO13	D7
Red LED	+	GPIO3	RX (D9)
Blue LED	+	GPIO2	D4
Green LED	+	GPIO15	D8
Yellow LED	+	GPIO16	D0

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Blynk Setup

1. Install Blynk IoT App (Android/iOS)

2. Create a New Template:

   • Name: Flood Detection
   • Hardware: ESP8266, Wi-Fi
   • Save Template ID, Device Name, Auth Token

3. Create a New Device using your template

4. Add Label/Gauge widgets:

   • V1 → Distance (cm)
   • V2 → Distance (inches)

5. Insert credentials into Arduino code:

#define BLYNK_TEMPLATE_ID   "YourTemplateID"
#define BLYNK_TEMPLATE_NAME "Flood Detection"
#define BLYNK_AUTH_TOKEN    "YourAuthToken"
char ssid[] = "YourWiFiSSID";
char pass[] = "YourWiFiPassword";

6. Optional: Enable cloud events in Blynk and trigger using Blynk.logEvent("high_water_levels")

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Libraries Required

• Blynk
• ESP8266WiFi

Note: OLED libraries are not required for this version.

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Upload Code

1. Connect ESP8266 via USB
2. Open .ino sketch and insert Wi-Fi & Blynk credentials
3. Click Upload
4. Open Serial Monitor at 115200 baud to verify connection

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Viewing Data

• Monitor V1 (cm) & V2 (inches) on Blynk dashboard
• Optional: set alerts for high_water_levels

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License

This project is licensed under the Apache License 2.0. See the LICENSE file for full details.

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Author

• Created with passion ❤ by: Roy Cuadra
• Updated Date: 10-24-2025

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Thank you for checking out this project! You are welcome to fork, improve, or use it for learning purposes.