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Make your Arduino board blink from the browser

We have finished to set up Arduino Web Editor in the previous post, so let’s make sure that our PC can talk to the Arduino board and we can upload our first program to it.

Article is based on information from The text of the Arduino getting started guide is licensed under a Creative Commons Attribution-ShareAlike 3.0 License. Code samples in the guide are released into the public domain.

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Tag: Project 001 Make your board blink from the browser

Project resources

Parts required

1. Arduino Nano and Mini-B USB cable or Arduino Uno with USB 2.0 Cable – A-Male to B-Male 1 pc


Step by Step instruction

 Arduino Web Editor (online Arduino Software)
  1. Double check if the Web Editor is displayed the way you like, check the Preferences panel for a few options;
  2. Connect your Arduino or Genuino board to your computer. Boards and serial ports are auto-discovered and selectable in a single dropdown. Pick the Arduino/Genuino board you want to upload to from the list.
  3. Let’s try an example: Choose Examples on the menu on the left, then Basic and Blink. The Blink sketch is now displayed in the code area.
  4. To upload it to your board, press the Upload button (arrow right) near the dropdown. A BUSY label replaces the buttons during code verifying and uploading. If the upload is successful, the message Success: Done uploading will appear in the bottom output area.
  5. Once the upload is complete, you should then see on your board the yellow LED with an L next to it start blinking. If this is the case congratulations! You have successfully programmed your board to blink its on-board LED!
blinking led on arduino board


/* Turns on an LED on for one second, then off for one second, repeatedly.
Most Arduinos have an on-board LED you can control. On the UNO, MEGA and ZERO it is attached to digital pin 13, on MKR1000 on pin 6. LED_BUILTIN takes care of use the correct LED pin whatever is the board used. If you want to know what pin the on-board LED is connected to on your Arduino model, check the Technical Specs of your board at

This example code is in the public domain.
modified 8 May 2014 by Scott Fitzgerald
modified 2 Sep 2016 by Arturo Guadalupi*/

// the setup function runs once when you press reset or power the board
void setup() {
// initialize digital pin LED_BUILTIN as an output
// the loop function runs over and over again forever
void loop() {
digitalWrite(LED_BUILTIN, HIGH); // turn the LED on (HIGH is the voltage level)
delay(1000); // wait for a second
digitalWrite(LED_BUILTIN, LOW); // turn the LED off by making the voltage LOW
delay(1000); // wait for a second

Wrapping Up

Sometimes your brand new Arduino/Genuino is already programmed with the Blink sketch, so you can’t tell if you are truly in control. If this is the case, change the delay time by changing the number in the parenthesis to 100, and upload the Blink sketch again. Now the LED should blink much faster. Congratulations! You really are in control! We have more than 500 DIY projects at!

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