John Teel

The one product protection that costs nothing is already inside your microcontroller. Most teams disable the watchdog timer during debugging and never turn it back on for production firmware.

A 3D-printed enclosure can fit together perfectly in your hand and still be impossible to mass produce. 3D printing follows no rules about part shape. Injection molding has a long list of them.

I built a sales team of independent reps who only got paid after the customer paid me. The one exception was my lead rep, who got a few hundred dollars a month for six months. Best money I ever spent.

For most battery products, the sleep current decides your battery life, because the device spends almost all of its life asleep. And nobody measures it on a dev board plugged into USB.

A 9V alkaline holds around 500 to 600 mAh, so you’re paying three to four times more per unit of energy than with a couple of AA cells. Then a linear regulator throws away two thirds of it as heat.

Undersized Copper Traces Will Overheat Your PCB

You don’t need to live in a big city, or especially in Silicon Valley, to make headway with a new product. I did it from two of the most remote locations in the United States.

A pre-certified wireless module covers the radio. Your layout, power supply, grounding, and enclosure all affect emissions, and you can absolutely fail FCC with a certified module inside.

Nuvoton N76 - The Cheap 8051 You've Never Heard Of

My chip was drawing current that hundreds of simulations said couldn’t exist. After weeks at a probe station and cutting the circuit apart with a laser, I found a transistor nobody designed.

A $4 module versus a $2 bare chip feels like leaving money on the table. Add the engineering time, the certification costs, and the RF layout, and the module wins until you’re at serious volume.

Routing a signal across a split in your ground plane is the most invisible mistake in PCB layout. The trace looks perfectly normal, every net checks out, and the return current detours around the gap in a huge radiating loop.

Antenna Keep-Out Zones - Ignore Them and Lose Range

The chips that power flagship phones are basically off-limits to startups. The datasheets are behind NDAs, minimum orders run tens of thousands of units, and unless you’re a huge customer, nobody’s answering your email.

A board with no test points can’t be tested in production. Test points are small exposed copper pads that cost nothing, and adding them later means a new board revision.

Thermal Vias - The Detail That Keeps Your PCB Cool

I spent about 9 months trying to convince investors to give me money for a product that was already in over 100 stores. Total investment: zero. What I actually needed was to lower my expectations.

A member built his design around the 9-axis MPU-9250. It went end-of-life mid-development, and the replacement ran its data lines at 1.8V, so he had to add level shifting just to talk to the new part.

A working prototype and a manufacturable product are two different designs. Founders consistently mistake the production redesign for a cleanup pass, and it’s a real engineering phase that takes 3 to 6 months.

A keyed connector is not reverse polarity protection. Customers defeat mechanical safeguards all the time, and a P-channel MOSFET on the power input protects the board for a few cents with almost no voltage drop.