Review on 🔑 Keywishbot Mini Nano Board ATmega328P 5V 16M Micro Controller Board – USB Cable Included – Compatible with Arduino Nano V3.0 (Pack of 3) by Louis Abrams

I should have gone with the nanos I usually buy but I chose these to try. You have an OLD bootloader and 4 out of 5 of those 3.3v don't work. I didn't notice it at first until I tried using the pin with a specific project. Tested the other 5 packs and found that only 1 of them had a working 3.3v pin, but the one with working 3.3v only output 4v on the 5v pin. Decided to pull out one of them to experiment with another. The sensor I just received. Just plugged the Nano into USB to make sure it wasn't one with a bad 5V contact and suddenly it made a hiss and magic smoke came out. Stay away from them. They certainly pose a threat.