Arduino LED Flasher Circuit

In this project, we will go over how to build an arduino LED flasher circuit.

We will use a standard arduino board, doesn’t matter which, and connect it so that it flashes an LED a certain amounts of times on and off repeatedly to create an LED flasher circuit.

An arduino is a self-contained microcontroller. Therefore, it can be programmed via the language Processing to turn the LED on for a certain period of time and turn it off for a certain period of time- over and over. To control the amount of time the LED will be on and the amount of time it will be off can easily be decided by our software code.

Once the arduino board is connected to a computer via USB, it has 5V of power. It gets power via the USB. The LED is then connected to its digital output pin. All we must then do is write our program which flashes the LED on and off.

Components Needed

  • Arduino Board
  • LED
  • USB Connector

The arduino board can be any of several. It can be an arduino uno, duemilanove, etc.

The 5 volts of power, again, comes from the USB connection from the arduino board to the computer.

The USB connector that needs to be used is one which has a USB type A connector on one side and a Type B connector on the other.

Arduino LED Flasher Circuit

To build this circuit, we simply connect the anode of the LED (the longer of the 2 ends) to digital pin 13 of the arduino board and the cathode of the LED to the ground Pin of the arduino board.

The circuit connected will look like this:

Arduino LED Flasher Circuit

The schematic diagram for this circuit is:

Arduino LED Flasher Circuit schematic

Once the circuit is connected in this way, all we have to do is take the USB connector and plug the type A connector into the computer and the type B connector into the arduino board.

The USB type A connector goes into the computer which will program the arduino and the USB type B connector goes into the arduino board. Now the arduino has direct connection to the computer and can be programmed. Arduinos are programmed via USB connections.

The last stage now is to write and then run the code which will make the LED connected to the board flash on and off.

Arduino LED Flasher Code

The code needed to flash the LED on the arduino board is shown below.

It is written in the processing language and ran through USB connection.

//Flashing LED Circuit

const int LED= 13;//LED connected to digital pin 13

void setup()
pinMode(LED, OUTPUT);  //sets the digital pin as output

void loop()
digitalWrite(LED,HIGH);  //turns the LED on
delay(1000);  //waits for a second
digitalWrite(LED,LOW);  //turns the LED off
delay(1000);  //waits for a second

For more detail: Arduino LED Flasher Circuit

This Post / Project can also be found using search terms:

  • arduino 3 led flasher
  • arduino led flash

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