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Andrew Dawes on Flickr


  • An LED
  • A 220 Ohm resistor (Red-Red-Brown-Gold)
  • Male to male jumper wires
  • A push button
  • Breadboard
  • 2 x AA (or AAA) batteries
  • AA (or AAA) battery holder with wires
  • A computer running Windows or OS X

For this issue we do away with complex micro controllers and CPUs and we go analog! We shall design a simple circuit to turn on an LED using a free application called Fritzing. Then we will challenge our family to build the circuit for real! Can they follow the instructions and create a flashing LED?

In this project we will learn

  • How to create circuits using Fritzing.
  • How a circuit works.
  • How to create a Bill of Materials (BoM).
  • How to use our diagram in applications.
  • Test our circuit diagram by building the project.

Fritzing is an open source application created to enable anyone to design circuits using electronic components. It is a powerful tool, yet it is accessible to all thanks to an interface that works in a similar manner to Adobe Illustrator / Inkscape. With Fritzing we can design circuits on breadboards, protoboards and circuit boards. We can then export those diagrams to use on the web or in Word / Powerpoint etc. We can even create a shopping list automatically in HTML format!

The best way to learn more about Fritzing is to use it, so lets install and get started!

Fritzing is a free application available for Windows, OSX and Linux computers. Download the version for your operating system and install as per the instructions. In this tutorial we shall be using the Windows version.

Fritzing presents us with a large breadboard, a component that enables us to test circuits without soldering. Breadboarding projects is always the first step when designing a new project. This is called the Breadboard area and it is where we will build or circuits. To the top right you can see the components in a section called “parts”. These are the parts with which we can make a circuit.

Just under the parts section, the bottom right of the screen is the “Inspector” which provides detailed information about a part and enables us to edit the properties of a part. For example if we select a resistor, we can change the resistance value to match our needs. Something that we shall do later.

We shall start our first circuit in Fritzing by deleting the large breadboard. Click on it and press the Delete key on your computer, or you can right click and select “Delete”. Now go to the Parts section and click on the spy / magnifying glass to search. But before we can search Fritzing will need to scan all of the parts.

Once done type in “3V battery” and press ENTER. When the search is complete look down the parts to find the “Battery” component. Left click on the component and in the Inspector section you will see that it is a battery pack. 2 x AA batteries for 3V. Now drag this part into the main area, we positioned it a little to the left, enabling us to build the circuit on the right.

So we have power, but now we need another component. This will be a resistor which can be found in the “Core” parts. It is the top left component. Drag a resistor into the Breadboard area and then take a look in the Inspector section. We need to change the resistance to 220? so using the dropdown menu for “resistance” do this. You will see that our resistor changes colour to Red-Red-Brown-Gold which is the correct four band colour code!

The resistor is used to stop the LED from drawing too much current from the batteries. LEDs are very greedy and well take as much current as they can get. This will give us a bright LED, but it will soon burn out. Using an LED means that we can reduce the amount of current that the LED can use and save the LED from burning out.

Lets add another component. We once again use the spy / magnifying glass to search, but this time we are looking for a “mini breadboard” and it should appear as the third component on the top row. Drag this to the Breadboard area and then place the resistor on top of the mini breadboard. The resistor will drop into place.

We have two components, our resistor and power supply, but they are not connected. So to connect them we need to draw a wire between them. To do this left click and hold the breadboard hole under the left leg of the resistor. Then drag the wire to the red wire of the power supply. Then let go.

The two are now joined together and this means that power from the battery can flow through the resistor. To change the colour of the wire we need to look to the Inspector section and change the colour to Red which is the traditional colour for wires handling voltages. We can change wire colours at any time. Just click on the wire and change it in the Inspector.

The next component that we require is an LED, a Light Emitting Diode. The LED can be found in the CORE section of parts, in the Output subsection. Drag the LED to the breadboard area but do not put it in the mini breadboard. Before we can use it we need to “Flip” it. Why? Well an LED is a diode and that means that current can only flow in one direction. So in order to use it in our project we need to click on “Flip” so that the bent leg of the LED is on the left. Now place the LED on the mini breadboard so that it the left leg is in the same column as the right leg of our resistor. This means that they are electrically connected in the circuit.

The next component is a push button, which can be found in the CORE parts under Input. This button is sometimes known as a momentary switch and when pressed it can make or break a circuit. Drag the push button to the breadboard and place it over the grey bar in the middle of the breadboard so that the top left leg is in the same column as the right leg of the LED.

The grey bar represents a break in connections between the top and the bottom halves of breadboard. The button will bridge over the gap. When the button is pressed it will connect the top left leg to the bottom right, enabling the flow of current from the red wire, via the LED and resistor, through the button and to the black wire (GND) which completes the circuit and causes the LED to light up. When the button is not pressed, the circuit is broken and the LED is unlit.

The last step is to make a connection from the bottom right of the push button to the GND (black wire) of the batteries. This will complete the electrical circuit. All we need to do is draw another wire from a hole in the same column as the bottom right leg to the black wire of the batteries. Again change the colour using the Inspector. Black is traditionally used to indicate Ground (GND).

Save your project as LED before moving on.

Fritzing makes it really easy to export our work for use online or in print. Go to File >> Export >> As Image and you will see that there are different options. We can export as bitmap images for use online or in documents or we can export as an SVG, PDF for use in vector applications like Adobe Illustrator or Inkscape. Exporting as an SVG is very useful if you wish to edit the diagram further, for example adding backgrounds and images to illustrate the project.

In this last part of Fritzing we look at how to create a shopping list of parts. Still in the export menu and we can see List of Parts (Bill of Materials). Click on this and it will ask you to name and save the file. The default name is the same as our Fritzing project and the save location is the same as where our project was saved. Click on Save and the Bill of Materials (BoM) will appear in a web browser. Showing us the exact parts we need for the project. This can be shared online, used as an insert for any projects / kits made with Fritzing.

Using the Fritzing diagram and the BoM challenge a member of your family, a friend or co-worker to build the circuit. Don’t give them any help, let them try it out and make a few mistakes before helping them.

A true test of a diagram is in how easy it is to use. Take for example Lego instructions. They show step by step the process to build a project and are regarded as some of the best instructions in the world!

Enjoy using Fritzing, and sharing your projects with others!

So what have we learnt?

  • How to design a circuit in Fritzing.
  • How to export our diagrams for use online / in print.
  • How to create a shopping list of parts (BoM).
  • How power flows through a circuit.
  • What an LED is.
  • How a resistor is used in a circuit.
  • How a push button can be used to control the circuit.

Learn More



Introduction to Fritzing


Fritzing tutorial


Creating your own parts


LED Blink with Fritzing


Fritzing diagrams


Custom parts for Fritzing