This example shows the simplest thing you can
do with an Arduino to see physical output: it blinks an LED.
Circuit
To
build the circuit, connect one end of the resistor to Arduino pin 13. This
resistor is required as current limiting resistor to an LED. Connect the long leg of the LED (the positive
leg, called the anode) to the other end of the resistor OR if two legs have
same length then see inside LED which have two parts big and small part, so big part is cathode(negative). Connect
the short leg of the LED (the negative leg, called the cathode) to the Arduino
GND, as shown in the diagram and the schematic below.
After
you build the circuit plug your Arduino board into your computer, start the
Arduino IDE, and enter the code below.
After
you build the circuit plug your Arduino board into your computer, start the
Arduino IDE, and enter the code below.
In
the program below, the first thing you do is to initialize pin 13 as an output
pin with the line
pinMode(13,
OUTPUT);
In
the main loop, you turn the LED on with the line:
digitalWrite(13,
HIGH);
This
supplies 5 volts to pin 13. That creates a voltage difference across the pins
of the LED, and lights it up. Then you turn it off with the line:
digitalWrite(13,
LOW);
That
takes pin 13 back to 0 volts, and turns the LED off. In between the on and the
off, you want enough time for a person to see the change, so the delay()
commands tell the Arduino to do nothing for 1000 milliseconds, or one second.
When you use the delay() command, nothing else happens for that amount of time.
Once you've understood the basic examples, check out the BlinkWithoutDelay example to learn how to create a delay while doing other things.
Code
/*
Blink
Turns on an LED on for one second, then off for one second, repeatedly.
This example code is in the public domain.
*/
// Pin 13 has an LED connected on most Arduino boards.
// give it a name:
int led = 13;
// the setup routine runs once when you press reset:
void setup() {
// initialize the digital pin as an output.
pinMode(led, OUTPUT);
}
// the loop routine runs over and over again forever:
void loop() {
digitalWrite(led, HIGH); // turn the LED on (HIGH is the voltage level)
delay(1000); // wait for a second
digitalWrite(led, LOW); // turn the LED off by making the voltage LOW
delay(1000); // wait for a second
}
Blink
Turns on an LED on for one second, then off for one second, repeatedly.
This example code is in the public domain.
*/
// Pin 13 has an LED connected on most Arduino boards.
// give it a name:
int led = 13;
// the setup routine runs once when you press reset:
void setup() {
// initialize the digital pin as an output.
pinMode(led, OUTPUT);
}
// the loop routine runs over and over again forever:
void loop() {
digitalWrite(led, HIGH); // turn the LED on (HIGH is the voltage level)
delay(1000); // wait for a second
digitalWrite(led, LOW); // turn the LED off by making the voltage LOW
delay(1000); // wait for a second
}
Once you've understood this example, check out the DigitalReadSerial example to learn how read a switch connected to the Arduino.
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