I'm playing around with the idea of using castellated edges to make two PCBs in one design (at least, for a very simple small design), and I was wondering if this would be the right way to go about it? The idea behind this was to make an all-in-one design for a really simple schematic rather than having two separate designs. This may not be the most elegant, but I wanted to see if the idea was feasible.
So in this schematic, I just have a simple IC with 4 connections. The idea is that on one PCB, there's a sensor with traces going to a pin header. The header connects to another PCB, which holds a connector that goes off-board. It's really straightforward, and I hope the 3D render with parts helps illustrate the idea.
To make this castellated board idea, I used holes to form the line where the PCB will be split in two. You can see that there in the image as J5. They look like copper holes, but they're non-plated through holes in KiCAD. There shouldn't be any copper associated with them despite the solder mask around them. Also, I had to play around with the net names a bit so that they'll connect through the header but they don't require traces to each other. Finally, the copper pours on the board are not tied to any net. That way, there shouldn't be any issues when the PCB is split.
What do you all think about this approach? Is it a good idea? Seems like a great idea in practice, especially since I'm not dependent on traces at the point where the boards separate. I just felt that having separate PCBs for something so simple was tedious. That way, I don't have to purchase them separately and have all boards together at once.