Basic Arduino Tutorials : 01 Blinking LED




In this instructable, I'm going to show you how to make a simple circuit/code with an arduino, which will make an LED connected to it flash from off to on, with 1-second intervals, as shown below. 
This is a very easy, basic idea, however it leads to many more complicated codes and circuits.

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Step 1: What You Will Need

1 x LED
3 x Cables
1 x 330 Ω Resistor
1 x Arduino board (it can be any kind, but for this instructable i used the UNO board).
1 x USB cable
1 x Computer with Arduino software installed ( if you haven't already got it)
1 x Breadboard

Breadboard/Circuit-board Holder.

Step 2: Attaching the Power Cables and Resistor to the Breadboard

Firstly you will need to plug one end of a wire into the '5v' Power output on the arduino, and the other end into the positive section of the breadboard.
Then you need to plug one end of a wire into the ground ('GND') Power output, and the other end into the Negative section of the Breadboard.
Finally, you need to plug one end of the resistor from the Negative section of the Breadboard, to any horizontal line on the main section. (NOTE- It is very important to use AT LEAST a 330 ohm resistor with this circuit. If you don't, then you will almost certainly blow the LED.)

Step 3: Attach the Control Wire to the Breadboard

Attach a wire from digital port '0' on your Arduino to the hole directly above the resistor.

Step 4: Attaching Led

Now to attach the Led into the circuit. Be warned, it will NOT do anything until you have uploaded the code to the board, which is done at a later stage.
the way this is done is to put it so that each pin is next to a wire/resistor. This sounds unclear, but pictures should help
You have to put the LONGER pin next to the wire connected to the port, and the shorter pin next to the resistor.

Step 5: Plug Into Computer.

Now you need to plug the arduino board into the computer. Nothing really to say here, just make sure that you don't break anything!

Step 6: Upload the Code to the Device

I've attached the code here. All that you have to do is open it with the arduino sketch program, and click upload to device

Step 7: And... Shazam

Once the code is uploaded, if you have done everything right, the LED should flash. It will do that for as long as the device is plugged in. 
Note- if the Arduino is unplugged, then plugged in again, it will still work.

Hope you enjoyed the instructable, keep looking at my profile for more arduino instructables soon.

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14 Discussions


3 years ago


I am using Arduino with RTC to operate the lights of my home.

I want at 10 PM all my lights should OFF and at 6 AM same should be ON.

I have completed everything but only unable to tell Arduino to read time from RTC to operate lights.

Can it be done by reading Arduino Serial Monitor? If yes, then HOW.

Also the other possible method to do same through Arduino.



3 years ago

There is no need to use the positive power rail for 5v from the arduino since you are just using the power from the digital pin.


5 years ago on Introduction


I'm just starting out with an Arduino and I did this project, but can't figure something out.

It seemed to me that the positive from the 5v to the breadboard doesn't really go anywhere, and I confirmed this by removing it. The LED still blinks. I'm assuming the circuit is completed by the jumper to the digital pin 0.

So, why the 5v jumper to the breadboard?

1 reply

Reply 3 years ago

You most certainly do not need a wire running from the 5v to the breadboard. The voltage you need is coming out of the digital I/O pin.


3 years ago

Very Nice Learning


4 years ago on Introduction

How would that work with the nano on the breadboard? I know that the Nan gets its power from the USB but what about all the plugs that the Nano is sitting in on the breadboard? I assume they are dead?

Here is a super easy Arduino breadboard:


Great tutorial!!
I'm new to all this stuff and before I jump into programming the Arduino I'd like to start by learning a little with analog circuits.

Can I use the Arduino purely as a power supply for my breadboard?


7 years ago on Introduction

Perfect for me and I'm so danged glad you posted this. If you have time, keep going! This is incredibly helpful. Thanks again!

Phil B

8 years ago on Introduction

I know there are a lot of Instructables on Arduino, but most of them begin beyond a beginner level. Arduino is very new and unfamiliar to me. I appreciate your very basic approach for a "newbie." I look forward to anything like a step-by-step tutorial for someone not currently involved with Arduino. Right now my questions involve, "What is it?" and "Why would I want to use it?" If I were to use Arduino, I would want it to do some useful and necessary task best done by it. I would not be interested in "cool" for the sake of "cool." Thanks.

1 reply
fergalPhil B

Reply 8 years ago on Introduction

That was my original idea, because when I started using Arduino, I couldn't find any tutorials on basic ideas, and I got very unnerved, So i made this tutorial for beginners, and am looking at making more. Thanks for the feedback!