Eagle CAD – Make Your Own Parts

In this tutorial, we are going to do a quick run-through of designing an Eagle CAD part. Instead of laboriously going from nothing to a completed part, we’ll be copying an existing part and improving it for our own purposes.

Later tutorials will focus on interpreting datasheets, testing, and design tips.


Eagle CAD is very powerful and has become very popular in the DIY community for a lot of reasons.  Being a very generous piece of freeware is one of them.  Eagle comes standard with a robust library of parts that work for a number of projects.

However, Eagle’s libraries are not just limited to the basic installation and the libraries available on their website.  There are several websites that offer some great parts for free.  A small list:



DIY Audio Circuits

The last one is my favorite resource.

Hi!  In this post, we’re going to make our own Eagle CAD part for our own library.

I strongly suggest that you make your own custom library as soon as possible.  If you are using other people’s libraries, you can easily fall victim to an outdated part or just a plain bad part design.  A bad part can ruin a PCB or require a hackjob solution of wires and Radioshack perfboards.

Open your copy of Eagle CAD

Open Eagle CAD PCB Software

Expand your Libraries section to reveal all of the parts at your disposal.

Basic installations of Eagle CAD come with some excellent parts, and more can be downloaded for free at Cadsoft’s website (INSERT LINK)

00_steve is my own personal library, named so that it would appear at the top of the Eagle CAD Parts Library drop-down.

Create a new library

FOr the purpose of this tutorial, I am using a similar naming convention as own personal library.    The library that we will be working with will be named ’00_new_library’.  The filetype extension for Eagle CAD libraries is ‘.lbr’.

Open the library you want to steal from

Press Symbol Button in the ‘rcl.lbr’ library.

select it with the group tool

Open your library in the same window.

Press the Symbol button to bring up the Edit menu

Create a new Symbol and name it RESISTOR (Eagle does not allow for lower case Symbol names).

Click paste and your copied schematic symbol should appear, ready to be pasted into your grid.

Make sure to place the center of the Symbol on the origin (the crossed lines in the middle.

This will ensure that your part will be able to be selected when clicking on the center of the part you are creating later in the schematic.

NOTE: do not change the grid until you have decided where your pin/pad connections are going to be placed.  Doing some ensures that your part will be able to have a wire/net connect to it.  Keep the grid at whatever it is.  You can change it  when you want to make the Symbol more intricate.

Create a new symbol
Press paste to paste the copied symbol
Save it after making any changes (name the pads, change up the drawing)

The first step is to open your library
Next make a new symbol.  You can use other peoples’ symbols by copying it.
Next make the layout.  This is the physical component that will require some thought.  Datasheets are pretty good for this purpose.
The final step is to go bring these two elements of your new part into a usable format.  You get to use it after this step.

As always, never trust a part until you have used it on a PCB.  Simple things can ruin a whole design.

Check out OSHPark for a really quick and easy solution for rapid prototyping.

The goal is to not reinvent the wheel and to reuse good work for your own purposes.

My library is available for free.  If you benefit from using a proven library, please feel free to donate any amount you think is fair.

A custom library of simple components you can source locally from Radioshack or popular audio parts will be posted shortly.