PSA: The WS2812B RGB LED has been revised, will require code tweak!
The WorldSemi WS2812B RGB LED has been revised with new silicon (date codes from 2017), and an unannounced change that is breaking current code has happened: the reset time has gone from 50 microseconds to 300 microseconds according to the datasheet. There is a visible difference between the parts:
The difference between the old and the new controller IC is apparent: the old one is rectangular whereas the new variant is square.
Here is a page from the updated datasheet:
So in order to get these to work the new minimum reset time is 300 microseconds, check your code!
Thanking Vladimir Pantelic for the information,
Make a robot friend with Adafruit’s CRICKIT – A Creative Robotics & Interactive Construction Kit. It’s an add-on to our popular Circuit Playground Express, FEATHER and other platforms to make and program robots with CircuitPython, MakeCode, and Arduino. Start controlling motors, servos, solenoids. You also get signal pins, capacitive touch sensors, a NeoPixel driver and amplified speaker output. It complements & extends your boards so you can still use all the goodies on the microcontroller, now you have a robotics playground as well.