WS2812 level translator
Bogdan of Electro Bob wrote an article on using the WS2812 level translator:
This entry was posted in how-to and tagged converter, micocontroller, WS2812.
Although the data sheet states that you would need at least 3.5V for them to recognize as HIGH level(70% of 5V), many seem to have no problem being driven from a 3.3V micro. With the signal regeneration that each does, it is only a problem for the first one in the chain. But, as I found out, some LEDs simply don’t work as the first device, and to be safe it is best to use a level translator. Unless you completely forget about it and find yourself in need of driving a display with WS2812 which does not like 3.3V signals.
Luckily there is a simple solution with parts that you have available: just another WS2812 LED (or two) and a diode. The trick is to power the first LED in the chain from 5V via a diode dropping its supply to 4.3V*. At this level the 3.3V signal from the microcontroller is within specifications to be recognized as a high level. As each LED does signal regeneration the output of the first LED will be at a 4.3V level which is in specification for the next LED powered at 5V…