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Arduino and ESP32-Based Smart Security System with Ultrasonic Sensor and GSM Module

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Circuit Documentation

Summary

This circuit integrates an Arduino UNO, an ESP32, an HC-SR04 Ultrasonic Sensor, a 0.96" OLED display, a Servo Motor 9G, a buzzer, and a SIM800L module. The Arduino UNO serves as the primary microcontroller, interfacing with the ultrasonic sensor, OLED display, servo motor, and buzzer. The ESP32 is used to communicate with the SIM800L module for sending SMS notifications.

Component List

  1. Arduino UNO

    • Description: A microcontroller board based on the ATmega328P.
    • Pins: UNUSED, IOREF, Reset, 3.3V, 5V, GND, Vin, A0, A1, A2, A3, A4, A5, SCL, SDA, AREF, D13, D12, D11, D10, D9, D8, D7, D6, D5, D4, D3, D2, D1, D0

  2. HC-SR04 Ultrasonic Sensor

    • Description: A sensor used for measuring distance using ultrasonic waves.
    • Pins: VCC, TRIG, ECHO, GND

  3. 0.96" OLED

    • Description: A small OLED display for visual output.
    • Pins: GND, VDD, SCK, SDA

  4. Servo Motor 9G

    • Description: A small servo motor used for precise control of angular position.
    • Pins: VCC 5V, PMW, GND

  5. Buzzer

    • Description: An audio signaling device.
    • Pins: PIN, GND

  6. ESP32 38 PINS

    • Description: A low-cost, low-power system on a chip microcontroller with integrated Wi-Fi and dual-mode Bluetooth.
    • Pins: GND, 23, 22/SCL, 1, 2, 21/SDA, 19, 18, 5, 17/TX2, 16/RX2, 4, 0, 15, D1, D0, CLK, 3V3, EN, VP, VN, 34, 35, 32, 33, 25, 26, 27, 14, 12, 13, D2, D3, 11, 5V/VIN

  7. SIM800L

    • Description: A GSM/GPRS module used for communication over cellular networks.
    • Pins: NFT, RING, VCC, DTR, RST, MIC +, RXD, MIC-, TXD, SPK+, GND, SPK-

Wiring Details

Arduino UNO

HC-SR04 Ultrasonic Sensor

0.96" OLED

Servo Motor 9G

Buzzer

ESP32 38 PINS

SIM800L

Code Documentation

#include <HardwareSerial.h>

// Create a HardwareSerial instance
HardwareSerial sim800(2); // UART2: GPIO16 -> RX, GPIO17 -> TX

// Pin to check if it gets HIGH (D1 is GPIO5 on ESP32)
const int triggerPin = 5;

void setup() {
  // Initialize Serial Monitor
  Serial.begin(115200);
  
  // Initialize SIM800 module
  sim800.begin(9600, SERIAL_8N1, 16, 17); // baud rate: 9600, RX: GPIO16, TX: GPIO17
  delay(1000);

  // Send initialization commands to the SIM800
  sendATCommand("AT");            // Basic check
  sendATCommand("ATE0");          // Turn off echo
  sendATCommand("AT+CMGF=1");     // Set SMS mode to text
  sendATCommand("AT+CSCS=\"GSM\""); // Set character set

  // Initialize triggerPin as input
  pinMode(triggerPin, INPUT);
}

void loop() {
  // Check if the D1 pin (GPIO5) is HIGH
  if (digitalRead(triggerPin) == HIGH) {
    // Send the SMS if the pin is HIGH
    sendSMS("+918767716641", "Target Detected At :- https://maps.app.goo.gl/9Pw447xSRKxQdCa97");
    
    // Optional: Add a small delay to prevent sending multiple messages if the pin stays HIGH
    delay(10000);  // Wait for 10 seconds before checking again
  }
}

void sendATCommand(String command) {
  sim800.println(command);
  delay(500);
  while (sim800.available()) {
    String response = sim800.readString();
    Serial.println(response);
  }
}

void sendSMS(String phoneNumber, String message) {
  Serial.println("Sending SMS...");
  sim800.println("AT+CMGS=\"" + phoneNumber + "\"");
  delay(1000); // Wait for the module to be ready
  sim800.println(message);
  delay(500);
  sim800.write(26); // CTRL+Z to send the message
  delay(5000); // Wait for response
  
  while (sim800.available()) {
    String response = sim800.readString();
    Serial.println(response);
  }
}

This code initializes the SIM800L module and sets up a trigger pin to send an SMS when the pin goes HIGH. The sendATCommand function sends AT commands to the SIM800L, and the sendSMS function sends an SMS to a specified phone number.