Electronics can be surprisingly easy and cheap to build these days. He designed the circuit and layout with software called KiCAD (free and open source) then submitted the designs to a fabrication house - probably a popular offshore one - that easily can handle that level of board and component placement complexity. It would probably cost only a few hundred to build and ship, with 1 month turnaround time.

You can also hand-assemble surface mount parts by applying solder paste carefully to the pads, then placing all the components on the paste and heating the board until all the solder melts. That would have very time consuming for all those LEDs!

There's also some homebrew pick-and-place machines and soldering ovens, but that's probably a bigger upfront investment than the offshore companies can offer.

As long as there aren't surprise 50% tariffs.

This was something I had to look into earlier this year. We found that even if tariffs were 200-300%, JLC and PCBway are still half the cost of domestic USA board houses, while also somehow providing half the leadtime. They are an absurdly good deal.

I remember William Osman (who established Open Sauce) talking about how they manufactured the badges for the convention, which are mostly just one large pcb, and how they looked into having them made in the US but there were no companies even offering the same kind of service. So it is not just that the Asian suppliers are cheaper, it is also that there isn't really a competitive US made alternative even if you were willing to pay more for it.

Here is the link to the episode (without a timestamp): https://www.youtube.com/watch?v=S78lYvjo2JQ

And this is how the badges looked/worked: https://www.digikey.com/en/maker/tutorials/2025/assembling-y...

Yep. And if you go to Shenzhen, some shops will take on varying amounts of board design and prototyping for you. It's possible to get boards fast and for cheap, like less than a few days and even cheaper when the goal is larger quantities for semi-serious products.

For a few hobby or toy things, the fixed rate board stuffing shops are the way to go.

You can get boards like these made for single-digit dollars per unit* even at prototype scale, through companies like jlcpcb.

*I haven't looked at the specific parts for this board, the LEDs look nice and could be a little pricey.

Boards, but can you get the pick and place and the soldering done? I wouldn't want to be soldering that many LEDs by hand!

Every major chinese PCB supplier has offered very affordable PCB assembly ("PCBA") for several years now where you give the gerbers for the boards along with a BOM with part numbers from a mutual supplier catalog and p'np / solderpaste mask data and they will load up a p'np machine and oven run a small batch of boards for you.

e.g.:

https://jlcpcb.com/smt-assembly

https://www.pcbway.com/pcb-assembly.html

That price is including PCBA. Without it would be <$1/board

>He must have worked with a company that can do the surface mount assembly

He did (there are centroid files in the production folder, which tell the board house where to put the components), but you'd be surprised at how possible it is to assemble something like this by hand. You won't believe me, but I find it easier than through-hole soldering (because you don't have to keep flipping the board over).

But there's a 99.9% chance this was done in-house at JLC or PCBWay.

Indeed, JLC for this one, though I did start off by hand assembling the first version with a 3D printed jig to locate the LEDs.

No need to reinvent the wheel. Hand assembling all those leds looks like a nightmare.

Yeah, wondering how the LEDs were aligned so precisely. Some kind of silicone grid-like jig to hold them while the solder reflows? Or is it just pick & place robotics doing what they do with precision?

The surface tension of the solder will pull them into alignment if the pad shape and solder volume are correct.