Mitchel Stoll

Customer Spotlight: Matt Campbell, Owner of Farix Embedded

 

Matt Campbell pushes the boundaries of staying busy. With all the different hats he wears, he is quite an impressive person! He's not just the co-owner of Circuit Happy, a modular synthesizer manufacturer, but he also owns his own company, Farix Embedded. We have really enjoyed getting to know Matt over the time he has owned his LumenPnP, and we love how he uses it for so many different needs. We hope you enjoy learning more about what Matt does and how he uses his LumenPnP.

Tell us a bit about yourself and what you make.

My name is Matt Campbell, and I run a one-person electrical engineering consultancy called Farix Embedded. I get to work with clients on a lot of cool projects in a bunch of different industries. I do board design, firmware, DSP development, embedded Linux, some application-level software, and whatever else is needed to solve problems. Before going independent, my career brought me through some academia research labs, medical devices, consumer devices, the music industry, and commercial 3d printers.

I am also the co-owner of a boutique modular synthesizer manufacturer called Circuit Happy. We design and produce the Missing Link series of products that bring Abelton Link clock synchronization to your desktop and Eurorack synthesizers. It’s a niche product, but it’s amazing hearing how we enable our customers' creativity and jamming.


What are you building with your LumenPnP? 

I am lucky to get to use LumenPnP for my day job, side job, and hobbies! For client projects, the LumenPnP has settled in as an additional tool beside traditional proto houses. It shines with low to medium-complexity boards, tight timelines, and mid-scale volumes. 

My side gig at Circuit Happy is what got me into the LumenPnP in the first place. In 2024, we brought PCBA production in-house from domestic contract manufacturers. As for hobby projects, when you have a desktop PnP, every problem in your life starts to look like a PCB waiting to happen ;).


What is your favorite feature of the LumenPnP?

Most of all, it's the open-source nature of the project with the hackability and self-service that it brings. It's awesome that you can trade money for time by buying the pre-assembled PnP from Opulo (and the great customer support!) but still have all the flexibility that comes with an open-source project. Along with the source files, BoMs, and assembly documentation, the community is also invaluable. It’s exciting to see the Discord discussions and user mods that get posted and keep upgrading and enhancing my machine.

How many boards a month do you produce with your machines?

I’m sure almost everyone says this, but it varies a lot by month. In December of 2024, I produced 250 PCBAs for a production run with Circuit Happy. In 2025, I expect to run 500 to 750 PCBAs a quarter (enough that we are considering a second LumenPnP). For client projects, I’ll average a prototyping run every month or two of about 10 boards at a time.


How were you building these boards before the LumenPnP?

Before the LumenPnP, it was a mix of hand assembly when doing single-digit prototypes and contract manufacturers/proto houses for anything beyond that. What is really insane to me is the fact that the LumenPnP literally paid for itself and a couple packs of feeders on the first production run when compared to using a domestic CM.


 

What has the LumenPnP enabled you to do that you previously couldn't?

The Lumen unlocked a level of flexibility in prototyping that just wasn't possible before. Before, it was risky to plan on 10-20 prototypes for a RevA, but it could get expensive and drawn out to plan on multiple runs with a proto-house. With the LumenPnP, I can assemble one panel, test it, and decide if I want to make tweaks before investing part stock in the remainder of the run. Scrapping a few panels is a lot cheaper than full prototypes!

  

What is the single most important piece of advice for people who are trying to get into PCBA production?

I’d start by getting very comfortable with hand assembly, rework techniques, and tools (soldering irons, hot air, tweezers, etc.).  After that, think about design for manufacture/assembly (DFM/DFA) as early as possible and adjust for your in-house process. Documentation and a few working prototypes are one thing, but turning that into hundreds of boards yourself is another.

When designing for the LumenPnP, I think about package types, single side boards, and especially part consolidation. Finally, much like with software, premature optimization or getting too clever for your own good will almost always get you in trouble. An easily producible board is always better than a clever but tricky over-optimized design.

P.S. There is no right amount of flux other than “more”.
  

What's your solder paste of choice? What do you use for a reflow oven?

So far, I have been using ChipQuik NC191SNL50. I hear ChipQuick gets a bad wrap, but I've had good luck with it, and you can get 50g jars on Amazon. I just bought a 500g tub of Loctite GC-10 and can't wait to try it out on my next production run.

For reflow, I use the Controleo3 from Whizoo Electronics. I get great and consistent results every time using the stock reflow profiles. I absolutely love that thing, and it’s great for baking parts and pre-heating tricky boards for rework, too. I built mine from the kit, and the build documentation is top-notch as well. One warning: it’s not a question of “if” but rather “when and how bad” you’ll cut yourself on the sheet metal when building it. The band-aide included in the kit is only partially tongue-in-cheek.

 




To keep up to date with what Matt Campbell is doing,
check out Farix Embedded and Circuit Happy (YouTube) (Instagram).