The WS2812B RGB LED shield

On this board we have the addressable WS2812B RGB LED. This LED is used in many LED chains.

The board uses D2 (GPIO 4) as data line (or GPIO 21 when running on the ESP32). Since the same line is used as SDA for I2C modules it cannot be used in conjunction with I2C shields.

Please note that D2 (GPIO 4) is also used as I2C SDA signal. For this reason the WS2812B cannot run together with an I2C shield.

From the software point of view a driver is already available in the micro Python library named neopixel. Accessing the WS2812B using this driver is the pretty simple.

Here is a program demonstrating this:

https://github.com/uraich/MicroPython_IoTDemos/blob/master/drivers/ws2812bLED/ws2812.py

Be careful with this LED and do not look into into when it emits light with full intensity. The light is so intense that you may damage your eyes!

In Cayenne we can define 3 sliders which control the intensity of each color component. The program subscribing top the slider control channels and driving the LEDs correspondingly is found here:

https://github.com/uraich/MicroPython_IoTDemos/blob/master/cayenne/ws2812b/cayenneWS2812B.py

There is also a little program simply switching the LED off:

https://github.com/uraich/MicroPython_IoTDemos/blob/master/cayenne/ws2812b/switchOff.py

-- Uli Raich - 2019-03-22

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