• Make an LED blink on and off at a 1-second interval using Arduino code.

• This demonstration illustrates the basic functionality of an Arduino by blinking the built-in LED.

Hardware Required:

• Arduino Board

• LED

• hook-up wires

• 220 ohm resistor

• You can use a resistor value other than 220 ohms with the LED, and the LED will still light up with values up to 1K ohms.

Software Required:

Arduino IDE 

Code:

• To begin, initialize the "LED_BUILTIN" pin as an output using a line of code in the Arduino Software (IDE).

pinMode(LED_BUILTIN, OUTPUT); 

• In the main loop, you turn the LED on with the line:

digitalWrite(LED_BUILTIN, HIGH);

• This supplies 5 volts to the LED Next, use a line of code to turn off the voltage supplied to the LED, causing it to turn off.

digitalWrite(LED_BUILTIN, LOW); 

• The delay() commands in the code create pauses of 1000 milliseconds (1 second) between turning the LED on and off. During these delays, the Arduino does nothing else. For more advanced timing techniques, explore the Blink  WithoutDelay example to learn how to create delays while performing other tasks. 

• Once you're familiar with this example, try the DigitalReadSerial example to learn how to read input from a switch connected to the Arduino board.

//Blink   (Turns an LED on for one second, then off for one second, repeatedly.)

1. void setup()    // initialize digital pin LED_BUILTIN as an output.

2. { 

3.   pinMode(LED_BUILTIN, OUTPUT);

4. }

5. 
   

6. // the loop function runs over and over again forever

7. 
   

8. void loop() {

9.   digitalWrite(LED_BUILTIN, HIGH);                  // turn the LED on (HIGH is the voltage level)

10.   delay(1000);                                                      // wait for a second

11.   digitalWrite(LED_BUILTIN, LOW);                  // turn the LED off by making the voltage LOW

12.   delay(1000);                                                     // wait for a second

13. }