This, full-size is something we do not want to do, so I’ve intentionally excluded it from being brought into my PcbDoc: Figure 3: Explicitly not importing the unstuffed parts The problem, of course, is that adding this to the schematic means it will import into my PCB for my smaller Pi hat board. I realized that I had a ton of extra room in my standard-size Raspberry Pi hat, so I decided to incorporate my AC-to-DC converter into the board. In my schematic, I have included all the components that exist across both designs (whether they are stuffed or not): Figure 2: Schematic with no variants There was some minor massaging required (e.g., cutouts, polygon pours, board outlines, etc.), but the components and routes stayed the same. After completing the routing, I copied and pasted the whole PCB design into my standard-size PCB (PiHat - Full.PcbDoc). I started out routing the Raspberry Pi Zero hat design since the standard size is essentially a larger version of the Zero. I have created two variants for my Kiln Controller: one for the Raspberry Pi (standard size) and the other for the Raspberry Pi Zero. You will also notice the variants at the top. In this example, I have created a single schematic with two PCBs: Figure 1: Project files including multiple PcbDocs Our objective here is to maintain a single source of truth within the schematics yet be able to route variants of the PCB itself. We will also be reviewing the example using the board from my last article, Pandemic Prototyping: Building Electronics from your Living Room. How do you handle the exact change across both projects? How do you guarantee those changes be identical? How many times will this occur (e.g., Rev A, B, C, etc.)? This article will review an approach to managing multiple PCB designs within a single project, ensuring your single source of truth.

Generally, this practice would be acceptable except when you need to go back and update the design. All too many times, I have seen designers fork (i.e., copy and paste) a project and then add slight variations to the schematic and/or PCB.

It seldom happens that we have a single project that requires multiple PCBs with various stuffing options, but when it happens, a lot of us tend to get stuck.

Now and then, we design using variants with different stuffing options. The majority of our PCB designs sit as a single PCB under our Altium Designer projects (i.e.PrjPcb file).

Altium multiple schematic sheets