The Expressive Pixels extension allows animations created with the free Expressive Pixels Windows App to be rendered on display arrays based on WS2812B (NeoPixels) RGB LEDs, such as the 16x16 Sparklet for micro:bit:
After creating a new MakeCode project, add the Expressive Pixels Extension by clicking on the Extensions button in the block picker, followed by searching for the word "expressive" (or entering the URL of this repo - https://github.com/microsoft/ExpressivePixelsMakeCode).
You should see that EPXDisplay and Neopixel are both added to the toolbox, as shown below:
Select the Neopixel section in the toolbox and create a strip (at pin P0 for the Sparklet for micro:bit) with the proper number of pixels (256 for the Sparklet for micro:bit). From the Advanced Pin section, add a digital write pin on P1 of value 1 to turn on the Sparklet display. Finally, from the EPXDisplay section, add the powerupclear block with low brightness ensures that the display is cleared and set to a nominal brightness:
In the Expressive Pixels application select the 'Copy Programmable MakeCode Binary declaration to Clipboard' ellipsis menuitem for the animation you wish to display on your MakeCode device's display. Make sure to specify the dimensions of your display array (16 x 16 for the Sparklet for micro:bit).
In the MakeCode editor, switch over to the JavaScript tab 
and paste in the declaration that is in the Windows Clipboard in the appropriate location below. Then call EPXisplay.writeAnimation sending the strip and buffer as first and second parameters. Finally, remember to call the show method on the strip!
Now download the MakeCode program to your device; the animation will play on your LED display array.
For the 16x16 Sparklet for the micro:bit, it's nice to be able to address the NeoPixel strip using
(x,y) coordinates. This can be done using the Neopixel extension by first calling set matrix width
(16 in the case of the Sparklet for micro:bit) and then calling set matrix color to set the color
at specified (x,y) coordinates, as shown below:
The resulting image should look like this:
- for PXT/microbit
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This project has adopted the Microsoft Open Source Code of Conduct. For more information see the Code of Conduct FAQ or contact opencode@microsoft.com with any additional questions or comments.