Where electronics and entrepreneurship intersect
Published on by John Teel
A working prototype doesn’t mean you’re ready to build a hundred of them. When you make a mistake on a prototype it costs you one board, but in a production run you copy that same mistake a hundred times. That can mean … read more
Published on by John Teel
The schematic mistakes in this article are small enough that most people never notice them until the boards come back. Break these rules and you can get units that die in customers' hands, boards where the chips can't talk to each other, … read more
Published on by John Teel
Capacitors are the most common part in your product, and the part nobody thinks about. They rarely get a second look, so the same seven mistakes show up in schematic after schematic that I review. One of them will fail safety certification … read more
Published on by John Teel
The firmware mistakes I'll discuss usually aren't noticed in a prototype, and none of them cause a problem until the product is already in customers' hands. One of these mistakes wears out the flash memory in a microcontroller in days instead of … read more
Published on by John Teel
That enclosure you 3D printed is likely impossible to mass produce. One of the reasons won't show up until your first production parts arrive. Another one turns a rock-solid prototype into a flimsy product the moment it comes out of a mold. … read more
Published on by John Teel
Two boards can be built from the exact same schematic, and one works perfectly while the other fails EMI testing, resets randomly, or has almost no wireless range. The schematic isn't the whole design, because it's really just an approximation of what … read more
Published on by John Teel
If you learned electronics through kits and tutorials, your prototype is probably missing every single protection in this video. And that's fine if it's just for your own use. But if you want to commercialize it, that changes everything. You've likely never … read more
Published on by John Teel
AliExpress is a great resource for a wide variety of Chinese-made components, but you have to be careful about the quality of what you actually get. And there are nine of them I'd never let anywhere near a product I'm building. One … read more
Published on by John Teel
Years ago with my own product I decided to seal the battery inside to keep the cost down, and that same decision today would shut it out of one of the world's biggest markets. Every battery in this countdown works perfectly on … read more
Published on by John Teel
Someone building his first product asked AI to design a small circuit for him. The answer came back in seconds, with every part labeled and every connection spelled out. He built it exactly the way AI told him to, and it didn't … read more
Published on by John Teel
If you learned electronics through beginner kits and tutorials, at least one of these sensors is probably sitting in your prototype right now. One of them has been discontinued for years. Another one can't legally ship in products sold in Europe. And … read more
Published on by John Teel
Your PCB layout is making enclosure decisions for you right now, whether you realize it or not. And most of them are wrong. Most product creators finish their board first, and then plan to design an enclosure around it later. And that's … read more
Published on by John Teel
Your manufacturer will build a thousand copies of a board that doesn't work. And they won't warn you first. That sounds like an accusation, but it isn't, because catching your design mistakes was never their job in the first place. Most product … read more
Published on by John Teel
Your prototype works. You plug it in, it does exactly what it's supposed to, and your brain tells you you're almost done. That little voice in your head is lying to you, and it's about to cost you months of wasted time … read more
Published on by John Teel
If you've built an early working proof-of-concept prototype using off-the-shelf parts, then you've proven exactly one thing, that your concept works. But what you can actually do with a prototype at that stage is limited, because in most cases it's not in … read more
Published on by John Teel
Getting your prototype to finally work is one of the best feelings in all of hardware development. You've been grinding on it for months, and now you're holding something that actually does what you set out to build. So it's natural to … read more
Published on by John Teel
These nine voltage regulators show up all the time in beginner designs and early prototypes. They work fine on the bench, but in a real product they cause thermal failures, blown EMC tests, and production problems that cost thousands of dollars to … read more
Published on by John Teel
Most product creators pick the ESP32-S3 by default because it's familiar, and then six months into development they realize it can't do what their product actually needs. The ESP32 lineup has exploded to over nine different variants, but three of them matter … read more
Published on by John Teel
The wireless module you pick can kill your product before it ever ships. I'm talking about FCC certifications that fall apart at the last minute, cellular networks that shut down mid-production, parts that go discontinued right when you're scaling, and clone modules … read more
Published on by John Teel
Pick the wrong microcontroller for your product and you're looking at a full board redesign, fresh certification fees, and months of lost time. The ESP32 versus RP2350 question is one I get asked constantly, and most comparison videos turn it into a … read more
