123D Circuits.io is a site where you can design circuits and PCBs in your browser for free.
This instructable will guide you through all the steps of creating and ordering a PCB.
Step 1: Getting started: creating an account
First you have to create an account at https://123d.circuits.io
You can also use Facebook or Twitter to log in.
Step 2: Creating a new circuit
On your dashboard, click "New Circuit".
Step 3: Creating a new project
Enter a name for your project, select the type of project (choose schematic circuit for this design), and click "Create new".
Step 4: Circuit design: The sidebar
Step 5: Circuit design: adding components
To add common components, you can drag them from the left sidebar. If you need more advanced components, click on the "Search Component" button. Here you'll be able to search for other components. You can append an asterisk (*) to search with prefix wildcards, for example "74HC*".
Another example, if you want to add a screw terminal, search for "connector" and choose one.
Step 6: Circuit design: component value
You can give your components a value by clicking on it and filling in the detail in the inspector appearing at the bottom of the screen.
Step 7: Circuit design: Connecting everything
To connect two points with each other:
- hover with your cursor over the component and click on the red square denoting a component terminal,
- click the other point in the schematic you want to connect it to (this can be either an existing wire or a terminal)
Step 8: Circuit design: Using labels
If your schematic is getting more complicated, you can keep it clean by using labels. The schematic on the 3 following screenshots is logically the same.
Step 9: PCB design
Now that he schematic is complete we can start designing the PCB. This process is often called "laying out a board" or simply "layout" since it involves laying copper traces on the PCB.
Click in the menubar on the left to go to the PCB design.
Step 10: PCB Design: Sidebar
Step 11: PCB Design: footprints
By default all the footprints are small surface mount components (SMD). If you want to change the footprint to through hole or any other package, select the component and choose the a different footprint in the pop-up menu.
Step 12: PCB Design: placing your components apart
Place your components such that not too many green lines cross and the design will be easily routable.