ESP8266 Community Forum

Hi!
So I was wondering if I can somehow easily control ws2815 with my nodemcu v3. I've noticed on web that those led strips require common ground with arduino, is it really true? Can I wire leds to 12v power supply, and then power nodemcu with 5v USB, or do I have to use some voltage converter from 12v to 5v?

Regards!

The 0V of the 12V supply should be tied to the 0V on the NodeMCU tp provide a common reference point.

The logic levels are poorly documented for the WS2815 with some implication that you need 70% of 12V supply for a logic high but that seems to be incorrect. Internally the WS2815 generates a 5V logic supply and the logic levels seem based on this. This means a minimum logic high of 3.5V and people report that trying to drive with 3.3V logic as per the NodeMCU does not work. So you need to level shift or buffer the output to provide 5V levels.

Have a look at the WLED Wiki
Here is a version using the Wemos D1 Mini

From own experience I know that controlling the data-in line of a normal WS2812B (5V) strip directly, but for quick testing purposes only.
If you want your ESP to live long, you'd really have to use a level-shifter.