PN Labs' Protect Nano Stops Power Supply Faults Ruining Your Microcontroller's Day

Montreal-based PN Labs is looking to save prototypists from blowing a microcontroller to bits with a compact power circuit protector suitable for breadboard use: the Protect Nano.

"My product is very simple," PN Labs' unnamed founder explains. "It's a power protection module that guards against over/under voltage, over-current, and reverse polarity events for embedded systems. It's adjustable via solder jumpers for 3.3, 5 and 12V with some wiggle room around those values. I had a whole batch assembled at a fab house, and the next question was how to ensure consistent quality across all the units."

The answer to that was found in the very devices the Protect Nano was designed to defend: a microcontroller development board, in this case an Arduino Nano R3. "I used a PWM [Pulse-Width Modulation] pin from an Arduino Nano to cycle through a range of voltages. I recorded the module’s response using the onboard ADC, then used some if/else logic to determine if it passed."

The Arduino Nano R3 is installed in a test rig with pogo pins. The Protect Nano is placed on top and secured with a toggle clamp, then tested to make sure that it correctly triggers for over- and under-voltage, then tests the electrical reset and finally "sound[s] a happy tone or sad tone on the buzzer" while printing the results to a compact OLED.

"I made [the Protect Nano] because I wanted something smaller than the original Protect module and more suited to lower voltages and lower currents," PN Labs' founder explains. "It is a versatile unit that can be used for many different applications, and I know it will save a lot of circuits in the field from being destroyed by adjustable power supplies being used wrong or going haywire!"

The Protect Nano is available to order on Tindie at $21.99 for a pair; PN Labs has not released design files for the board, but has made KiCad projects files available for its predecessor the Active Power Protection Module (APPM). More information on the test rig is available in PN Labs' Reddit post.