On 2-2-2022, I established that I don't need 2 PCBs. I just need one that folds.

I knew I wanted to try sandwiching an ATtiny84A between two flex PCBs, but before this I had been envisioning two disconnected PCBs, held in place with some structural solder or something along those lines. But then I saw this cursed connector by Joey Castillo, which got me thinking about a folding connector instead. Joey got it to work for a single-sided 5-trace Micro-USB connector, would it work for a two-sided 24-trace USB-C connector?

I'm delighted to say that the folded flex USB-C works. For this demo I didn't want to use one of my precious BGA chips, so I went with a hand-solder-friendly ATtiny85 circuit like the Nanite or Digistump uses.

Of course, using two flex PCBs adds some thickness. With OSH Park flex PCBs, an ATtiny84A sandwich would be around 0.9mm thick. Other vendors default to thinner substrates, but their prices are significantly higher for wee PCBs like mine. Anyway, I'm no longer adhering to the 0.7mm thickness requirement, let's get weird 😎