We want to show you how great Fritzing is when it comes to going from your breadboarded prototype to a polished, Etchable PCB design. We are going to utilize a completed circuit we used for our SPI Arduino tutorial that uses a shift register to control an array of LEDs. We are going to turn that circuit into a SHIELD for our Arduino Uno using Fritzing.
To export a working etchable PDF/SVG, PCB version of an Arduino Shield using Fritzing Circuit Design Software.
What you’ll need:
- Fritzing Sketch of your prototype circuit with everything connected correctly.
- Fritzing installed on your PC
Switch to PCB View
If you have assembled your circuit in the breadboard view of Fritzing, go ahead and change your view to the PCB view using the navigation bar along the top of your workspace. As Fritzing uses Inches by default, you may also want to change the grid options (and units) for your PCB view; this is done via the View > Set Grid Size menu option.
Getting around the PCB View
First up let's learn how to do the basics in this view, a quick rundown of the controls is:
- Select a component – use Left Click
- Component Group Selection Box - Left Click + drag to drag out a group select box.
- Move a component - Left Click + drag when a component is already selected.
- Edit Label - Double left click component label
- Additional Component Options – Right Click component
- Pan - Middle mouse click + Drag
- Zoom view on Mouse Pointer - Middle mouse scroll.
- Rotate components - using the quick access button red ribbon at the base of the workspace. Click the tiny little arrow to change direction and degree of rotation.
You will see a dark gray grid workspace, the black outline of your Arduino (or your MCU), and a gray box peppered with labeled yellow holes. The gray box is your PCB workspace; you can resize it by dragging the corners in/out. I’d recommend that you resize your PCB to be similarly sized to the Arduino Board.
If you look at any component’s ‘mask’ we notice it has a thin, dashed line connecting its legs to where it was connected on your breadboard prototype. These are known as rats-nest connections within circuit design systems. They represent a physical connection between components, in this case, they are imported from our breadboard view.
Get started rotating and maneuvering your components around your PCB. Try to ‘untangle’ your rats nest traces as much as possible to make later steps faster. A limitation here is that Fritzing is limited to 2 separate copper masks per PCB. With the addition of vias (conductive pathways through the board), 2 is more than enough for our basic to intermediate circuits.
Design Rules Check and Auto Routing traces
When you are satisfied that your components are sensibly placed on your board, we are going to ensure that there are design errors. Go to the Routing Menu option and select Design Rules Check (Keyboard Shortcut Ctrl + Shift + D). If you encounter any errors during this step don’t panic. Fritzing will highlight the component that is causing the error and you will have to use a little common sense to fix the error up before re-doing the design check.
So if your parts are all oriented as sensibly as possible and you have successfully completed a Design Rules Check, go ahead and use the AutoRoute feature. This will work through all different methods of connecting all the rat's nest traces of your PCB together. Let it run the simulation until it successfully completes.
Hopefully, at this stage, you will have all traces routed successfully and your PCB will be close-to-complete! If you want to hide the black labels of components or the outlines of the components from your finished view head to the View menu and deselect the Silkscreen Layer options.
We can now use the File > Export menu to select a file type we wish to export our PCB as. We chose an Etchable PDF format. Fritzing will generate a PDF/SVG file for each of the layers in the PCB design.
Professional Printed Circuit Boards made for you.
So now we have designed and exported our Arduino Shield for the SPI LED Array. Cool! The next step you would be taking would be to actually fabricate the PCB yourself. There are many options available to do so but since we’re using Fritzing for this whole tutorial and they provide such a great service we may as well give them a plug.
Fritzing FAB is a way that consumers can order any size/quantity of professionally made PCBs shipped worldwide. All you need is the files you generated by following this tutorial, which you send to Fritzing FAB. They will take a quick look at the files to make sure you aren’t throwing your money away on something that won’t work and then get to work manufacturing the boards.
The service encourages people to buy more than one of their circuit boards as they charge per size and amount, the more you buy the cheaper it gets per unit. They include a FAQ and pretty clear direction throughout the whole process, definitely, check it out if you are looking to produce your PCBs in larger quantities.