For bro 2.0

Notes & Credits

#include <Servo.h> #include <Wire.h> #include <LiquidCrystal_I2C.h>   const int trigPin = 9; const int echoPin = 8; const int redLED = 7; const int yellowLED = 6; const int greenLED = 5; const int buzzer = 4;   Servo myServo; LiquidCrystal_I2C lcd(0x27, 16, 2); // Adjust to 0x3F if LCD doesn’t display   long duration; int distance;   void setup() {   Serial.begin(9600);     pinMode(trigPin, OUTPUT);   pinMode(echoPin, INPUT);   pinMode(redLED, OUTPUT);   pinMode(yellowLED, OUTPUT);   pinMode(greenLED, OUTPUT);   pinMode(buzzer, OUTPUT);     myServo.attach(3);   myServo.write(0);     lcd.init();        // Initialize LCD   lcd.backlight();   // Turn on backlight   lcd.setCursor(0, 0);   lcd.print("Ultrasonic Test");   delay(2000);   lcd.clear();     // Test LEDs and buzzer at startup   digitalWrite(redLED, HIGH);   digitalWrite(yellowLED, HIGH);   digitalWrite(greenLED, HIGH);   tone(buzzer, 1000);   delay(1000);   digitalWrite(redLED, LOW);   digitalWrite(yellowLED, LOW);   digitalWrite(greenLED, LOW);   noTone(buzzer); }   void loop() {   // Send ultrasonic pulse   digitalWrite(trigPin, LOW);   delayMicroseconds(2);   digitalWrite(trigPin, HIGH);   delayMicroseconds(10);   digitalWrite(trigPin, LOW);     // Read the echo   duration = pulseIn(echoPin, HIGH, 30000);   distance = duration * 0.034 / 2; // Convert to cm     Serial.print("Distance: ");   Serial.print(distance);   Serial.println(" cm");     // Display on LCD   lcd.setCursor(0, 0);   lcd.print("Distance: ");   lcd.print(distance);   lcd.print(" cm   ");     // LED + Servo + Buzzer control   if (distance > 20 && distance < 400) {     // SAFE     digitalWrite(greenLED, HIGH);     digitalWrite(yellowLED, LOW);     digitalWrite(redLED, LOW);     noTone(buzzer);     myServo.write(0);       lcd.setCursor(0, 1);     lcd.print("Status: SAFE    ");   }    else if (distance <= 20 && distance > 10) {     // WARNING     digitalWrite(greenLED, LOW);     digitalWrite(yellowLED, HIGH);     digitalWrite(redLED, LOW);     noTone(buzzer);     myServo.write(45);       lcd.setCursor(0, 1);     lcd.print("Status: WARNING ");   }    else if (distance <= 10 && distance > 0) {     // DANGER     digitalWrite(greenLED, LOW);     digitalWrite(yellowLED, LOW);     digitalWrite(redLED, HIGH);     tone(buzzer, 1000);     myServo.write(90);       lcd.setCursor(0, 1);     lcd.print("Status: DANGER  ");   }    else {     // No object detected     digitalWrite(greenLED, LOW);     digitalWrite(yellowLED, LOW);     digitalWrite(redLED, LOW);     noTone(buzzer);       lcd.setCursor(0, 1);     lcd.print("Status: NO OBJ  ");   }     delay(300); }