void setup () { 
     // put your setup code here, to run once: 
    }
    void loop () { 
     // put your main code here, to run repeatedly:
    }

   pinMode(13, OUTPUT); // sets pin 13 as output pin
     pinMode(13, INPUT); // sets pin 13 as input pin 

   digitalWrite (13, LOW); // Makes the output voltage on pin 13, 0V
    digitalWrite (13, HIGH); // Makes the output voltage on pin 13, 5V 
    int buttonState=digitalRead(2); // reads the value of pin 2 in buttonState 

   const int pwm = 2 ; //initializing pin 2 as ‘pwm’ variable
    void setup()
    {
         pinMode(pwm, OUTPUT) ;     //Set pin 2 as output
    }
    void loop()
    {
         analogWrite(pwm,25);        //setting pwm to 25 
         delay(50);             //delay of 50 ms
         analogWrite(pwm,50);   
         delay(50); 
         analogWrite(pwm,75); 
         delay(50); 
         analogWrite(pwm,100); 
         delay(50); 
         analogWrite(pwm,125); 
         delay(50); 
         analogWrite(pwm,150); 
         delay(50); 
         analogWrite(pwm,175); 
         delay(50);
         analogWrite(pwm,200); 
         delay(50); 
         analogWrite(pwm,225); 
         delay(50); 
         analogWrite(pwm,250); 
    } 

   const int pwm = 9;   //naming pin 2 as ‘pwm’ variable 
    const int adc = 0;  //naming pin 0 of analog input side as ‘adc’
    void setup ()
    {
        pinMode(pwm, OUTPUT) ;     //setting pin 2 as output
    }
    void loop()
    {
        int adc = analogRead(0) ;   //reading analog voltage and storing it in an integer 
        adc = map(adc, 0, 1023, 0, 255);  
        /*
            ----------map funtion------------the above funtion scales the output of adc, which is 10 bit and gives values btw 0 to 1023, in values btw 0 to 255 form analogWrite funtion which only receives values btw this range
       */
        analogWrite(pwm, adc) ; 
    }

   const int buttonPin = 2;// the number of the pushbutton pin
    const int ledPin =  13;      // the number of the LED pin

    // variables will change:
    int buttonState = 0;     // variable for reading the pushbutton status

    void setup() {
      // initialize the LED pin as an output:
      pinMode(ledPin, OUTPUT);
      // initialize the pushbutton pin as an input:
      pinMode(buttonPin, INPUT);
    }

    void loop() {
      // read the state of the pushbutton value:
      buttonState = digitalRead(buttonPin);

      // check if the pushbutton is pressed. If it is, the buttonState is HIGH:
      if (buttonState == HIGH) {
        // turn LED on:
        digitalWrite(ledPin, HIGH);
      } else {
        // turn LED off:
        digitalWrite(ledPin, LOW);
      }
    } 

    int red = 10;
    int yellow = 9;
    int green = 8;
    void setup()
     {
        pinMode(red, OUTPUT);
        pinMode(yellow, OUTPUT);
        pinMode(green, OUTPUT);
    }
    void loop()
     {  
        // green and red off, yellow on for 3 seconds
        digitalWrite(green, LOW);
        digitalWrite(red, LOW);
        digitalWrite(yellow, HIGH);
        delay(3000);

        // turn off yellow, then turn red on for 5 seconds
        digitalWrite(yellow, LOW);
        digitalWrite(green, LOW);
        digitalWrite(red, HIGH);
        delay(5000);

        // red and yellow on for 2 seconds (red is already on though)
        digitalWrite(green, LOW);
        digitalWrite(red, LOW);
        digitalWrite(yellow, HIGH);
        delay(2000);

        // turn off red and yellow, then turn on green
        digitalWrite(yellow, LOW);
        digitalWrite(red, LOW);
        digitalWrite(green, HIGH);
        delay(3000);
    } 

   /*
      LiquidCrystal Library - Hello World

     This sketch prints "Hello World!" to the LCD
     and shows the time.

      The circuit:
     * LCD RS pin to digital pin 12
     * LCD Enable pin to digital pin 11
     * LCD D4 pin to digital pin 5
     * LCD D5 pin to digital pin 4
     * LCD D6 pin to digital pin 3
     * LCD D7 pin to digital pin 2
     * LCD R/W pin to ground
     * LCD VSS pin to ground
     * LCD VCC pin to 5V
     * 10K resistor:
     * ends to +5V and ground
     * wiper to LCD VO pin (pin 3)

    */

    // include the library code:
    #include <LiquidCrystal.h>

    // initialize the library by associating any needed LCD interface pin
    const int rs = 12, en = 11, d4 = 5, d5 = 4, d6 = 3, d7 = 2;
    LiquidCrystal lcd(rs, en, d4, d5, d6, d7);

    void setup() {
      // set up the LCD's number of columns and rows:
      lcd.begin(16, 2);
      // Print a message to the LCD.
      lcd.print("hello, world!");
    }
    void loop() {
      // set the cursor to column 0, line 1
      lcd.setCursor(0, 1);
      // print the number of seconds since reset:
      lcd.print(millis() / 1000);
    } 

    // Include the Servo library 
    #include <Servo.h> 
    // Declare the Servo pin 
    int servoPin = 3; 
    // Create a servo object 
    Servo Servo1; 
    void setup() 
    { 
       // We need to attach the servo to the used pin number 
       Servo1.attach(servoPin); 
        }
    void loop()
    { 
        // Make servo go to 0 degrees 
        Servo1.write(0); 
        delay(1000); 
        // Make servo go to 90 degrees 
        Servo1.write(90); 
        delay(1000); 
        // Make servo go to 180 degrees 
        Servo1.write(180); 
        delay(1000); 
    } 

   // This code is for testing the active buzzer
    int buzzerPin = 11;// initializing the buzzer pin at pin 11 of Arduino
    void setup(){// Code written in it will only run once

        pinMode(buzzerPin, OUTPUT);// This will set the pin 11 as output
        beep(50); // This will make a beep sound Beep
        beep(50);
        delay(1000);//Adding a delay of 1 sec.
    }
    void loop(){ // Code written in it will run continuously
        beep(50); // This will make a beep sound after every 500 milliseconds
        delay(1000);// Adding a delay of one second.
    }
    void beep(unsigned char delayms) {// Created a function for beep
        analogWrite(buzzerPin, 20); // This will set pin 11 to high
        delay(delayms);// Giving a delay
        analogWrite(buzzerPin ,0);// This will set pin 11 to LOW
        delay(delayms);// Giving a delay
        }