Where electronics and entrepreneurship intersect
Published on by John Teel
A product can work perfectly every time you use it and still fail certification the first time it goes into the test lab. That’s because the lab checks things your own testing never does, like how much electrical noise your product gives … read more
Published on by John Teel
The ESP32 is easy to get working on a prototype, but turning that prototype into a product is where things go wrong. One pin wired the wrong way can stop your finished product from booting, one antenna swap can leave you paying … read more
Published on by John Teel
Grounding feels like the easiest part of PCB design, since you just connect everything to ground and move on. But most of what we were taught about ground is a simplification. It stops being true once your board has high currents, fast-switching … read more
Published on by John Teel
Your power supply feeds every other circuit in your product, so when it goes wrong, everything else goes down with it. Pick the wrong regulator and a battery that should last a year can be dead in about a week. Ignore peak … read more
Published on by John Teel
The moment you click order on a PCB, every mistake in your design gets locked into copper. Almost every new board design comes back with at least one problem, and each one can cost you a new board order, another round of … read more
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
