“Biscuit Board” Blank PCBs with Pre-Made Vias for Rapid Home Prototyping

Professional PCB fabrication services these days are amazing, giving you the ability to get very high-quality PCBs at affordable prices in just a week or two. But what if you need to iterate your PCB designs quickly and don’t have time to wait that long? Then you’ll want to consider PCB fabrication techniques you can perform at home. That does, however, leave the problem of vias. To solve that, Stephen Hawes came up with this “Biscuit Board” idea that is really compelling.

Vias are like copper tunnels that connect traces on one layer of a PCB to traces on another layer. They’re important, because it is often impossible to route a trace without crossing an existing trace. With a via, you can switch your trace to another layer and continue on. But vias are really difficult to add to DIY PCBs made with conventional home lab techniques, like etching, milling, and laser engraving.

The solution Hawes came up with, which his commenters have dubbed “Biscuit Board” through consensus (the project is called “Viagrid” on GitHub), is a kind of PCB blank with several pre-placed vias in standardized positions. The PCB designer loads a template that contains those via locations, so they can use them to route traces as needed. They can then use a laser or CNC mill to cut the traces just like they normally would and the vias will already be where they should be.

Another key element of the Biscuit Board concept is consideration for origin and design placement. Hawes was specifically thinking about UV laser engraving machines, like the ComMarker Omni 1 and Omni X, when he designed the Biscuit Board blank. It has special shapes in the corners that make it easy to line up the laser preview on the board, so the traces perfectly overlap with the existing vias. People using CNC mills instead of lasers can set the origin even more accurately using traditional techniques.

This is one of those ideas that is just plain useful. Simply stock up on a bunch of Biscuit Boards, then you’ll be ready to make prototype PCBs with vias whenever you need them. If this takes off, it is easy to imagine Biscuit Boards available in a wide variety of shapes, sizes, and via densities.

If you want to try this for yourself, the current PCB design and template are available on the Viagrid GitHub page. Hawes is also accepting requests for boards from people who are seriously interested in helping with testing and development.