Program 2: Read a switch, print the state out to the Arduino Serial Monitor

  • Step 1: Take a arduino uno board, breadboard, button, jumper wires (male to male) and printer wire (to connect arduino board to PC).


  • Step 2: Connect the circuit as shown in below figures.


    • Read a switch, print the state out to the Arduino Serial Monitor
    Read a switch, print the state out to the Arduino Serial Monitor

  • Step 3: Write a program in Arduino uno desktop editor IDE. By opening new sketch.


  • Step 4: Save file, compile it and upload. 


    •  
// digital pin 2 has a pushbutton attached to it. Give it a name:
int pushButton = 2;

// the setup routine runs once when you press reset:
void setup() {
  // initialize serial communication at 9600 bits per second:
  Serial.begin(9600);
  // make the pushbutton's pin an input:
  pinMode(pushButton, INPUT);
}

// the loop routine runs over and over again forever:
void loop() {
  // read the input pin:
  int buttonState = digitalRead(pushButton);
  // print out the state of the button:
  Serial.println(buttonState);
  delay(1000);        // delay in between reads for stability
}

Explanation of code

  • In setup(), we provide the speed of serial communication. Then using pinMode() we initialize port 2 i.e. digital port of arduino uno , to obtain input from the button.


  • The button when released sends a 0V current to port 2 . Since port 2 is digital it receives it as 0. The buttonState variable is set to 0 and displayed on the serial monitor.


  • Similarly when the button is pressed, the current of 5V is given to port 2, which receives it as 1. The buttonState variable is set to 1 and displayed on the serial monitor.


  • The buttonState is monitored every 1000ms and hence the delay() is used.


Program 3: Demonstrates the use of analogWrite() to fade an LED

  • Step 1: Requirements are arduino uno, breadboard, jumper wires, register, LED and arduino desktop IDE. Connections should be made as shown below.


    • Demonstrates the use of analogWrite() to fade an LED
    Demonstrates the use of analogWrite() to fade an LED

  • Step 2: Write a program in Arduino uno desktop editor IDE. By opening new sketch.


  • Step 3: Save file, compile it and upload. 


    •  
int led = 9;           // the PWM pin the LED is attached to
int brightness = 0;    // how bright the LED is
int fadeAmount = 5;    // how many points to fade the LED by

// the setup routine runs once when you press reset:
void setup() {
  // declare pin 9 to be an output:
  pinMode(led, OUTPUT);
}

// the loop routine runs over and over again forever:
void loop() {
  // set the brightness of pin 9:
  analogWrite(led, brightness);

  // change the brightness for next time through the loop:
  brightness = brightness + fadeAmount;

  // reverse the direction of the fading at the ends of the fade:
  if (brightness <= 0 || brightness >= 255) {
    fadeAmount = -fadeAmount;
  }
  // wait for 30 milliseconds to see the dimming effect
  delay(30);
}