ESP8266 Community Forum

- Fri Dec 11, 2015 9:23 pm #36252 I recently purchased a Node MCU 1.0 board and have been playing with it the last couple of days. I have it up and running and everything seems fine, but I cannot get it to work on any power source other than a USB cable connected to a PC. I have tried supplying 5V to the VIN pin both with and without also supplying 3.3V to one of the respective pins, and I have also used a USB cord plugged into a power adapter to supply 5V through the USB port without being connected to a PC. The only behavior I get with all of those methods is that the blue LED by the WiFi antenna flashes briefly and D0 and D4 go high (I have LEDs on D0-D7). The board will only execute its stored program if powered by a USB cable connected to a PC. This is crazy. I have to be overlooking something simple... I hope.

- Sat Dec 12, 2015 9:46 am #36270 Ok. Please disregard. I believe I found my mistake and I'm too embarrassed to post it here

- Sun Dec 13, 2015 3:47 am #36309 Please share so that others can avoid this mistake.

ajb2k3.wordpress.com

I suffer from a bad case of random misfiring synapses!

- Sun Dec 13, 2015 7:52 am #36320 Well, I really hope no one would make this very rookie mistake. I was very hasty in wanting to get my project running that I did not pay close attention to the output specs of the power supply I was using. It's been a few years since I have played around with my electronics prototyping stuff that I've forgotten what all I have. I saw 12V written on the power supply (a "wall wart" style transformer) and thought that would be great since my voltage regulators are rated for up to 35V. What I failed to realize until after a couple days of being utterly perplexed by the behavior I reported, was that the output was AC instead of DC. Needless to say, I felt like a total idiot. I'm lucky that I didn't fry any of my circuitry. Moral of the story: don't be in a hurry and make sure you read the specs of your parts carefully