IoT Security System

ESP8266 Motion Detection & WhatsApp Alert System

Smart intrusion detection using ESP8266 NodeMCU, HC-SR04 ultrasonic sensor, LED indication and Twilio WhatsApp notifications for real-time security monitoring.

ESP8266 Controller

HC-SR04 Detection

Twilio WhatsApp

Project Overview

This project is an IoT-based security monitoring system built using ESP8266 NodeMCU and an HC-SR04 ultrasonic sensor.

Whenever a person enters the detection zone, the ESP8266 immediately activates an LED indicator and sends a real-time WhatsApp alert using the Twilio API.

The system maintains visitor counts, timestamps using NTP servers, and provides a low-cost security solution for homes, offices, laboratories and smart monitoring applications.

View GitHub Repo

Core Hardware Modules

NodeMCU ESP8266 Wi-Fi processor managing sensor inputs and cloud synchronization.

MFRC522 RFID Contactless proximity validation for authorized access tokens.

HC-SR04 Ultrasonic Precision sonar distance checks for vehicle detection.

SG90 Servo Motor Mechanical barrier control for physical gate actuation.

Project Resources

ESP8266 Firmware Firmware for motion detection, visitor counting, LED indication and WhatsApp notifications.

Hardware Connections Complete NodeMCU, HC-SR04 and LED wiring guide.

Pin Configuration

Component	NodeMCU Pin
HC-SR04 TRIG	D1 (GPIO5)
HC-SR04 ECHO	D2 (GPIO4)
LED Indicator	D5 (GPIO14)
VCC	VIN
GND	GND

Project Source Codes

1. ESP8266 Motion Detection Firmware

Controls ultrasonic motion detection, visitor counting, LED indication, NTP time synchronization and Twilio WhatsApp notifications.

Download Arduino Code

View Source Code



#include 
#include 
#include 
#include 

// ESP8266 Motion Detection
// HC-SR04 Ultrasonic Sensor
// Twilio WhatsApp Alerts
// LED Indicator
// Visitor Counter

// Complete source available in download