Setup Adafruit Circuit Playground Express for CircuitPython

We'll need to get our board setup so we can run CircuitPython code. First thing we'll need to do is connect the board to your computer with a microUSB cable. Then double-click on the reset button to put it in "UF2" boot-loader mode. The NeoPixels will turn green. The board will then show up as a USB storage device on your computer named "CPLAYBOOT". 

Follow the guide below to setup the firmware, once complete, come back here and proceed.

Download Adafruit CircuitPython Library Bundle

In order to run the code, we'll need to download some libraries. The download linked below will contain all the libraries available for Circuit Python. To run the code for this project, we only need a few. Unzip the downloaded file and look for the following libraries.

Required Libraries 

  • Adafruit Neopixel – neopixel.mpy
  • Adafruit Circuit Playground – adafruit_circuitplayground

Install Circuit Python Libraries 

Now that we have all of the libraries and know which ones this project needs, we'll need to copy them onto the Circuit Playground Express USB drive (which will be named CIRCUITPY after flashing the firmware). In the CIRCUITPY drive, create a new folder and name it "lib". Then, copy the libraries to that "lib" folder. The lib folder should contain neopixel.mpy and adafruit_circuitplayground.

Upload Code

OK, now it's time to upload the code for this project onto the CIRCUITPY drive. Create a new text document using a text app. Then, copy the code below and paste it into that newly created text document. Save that text document to the CIRCUITPY drive and name it "main.py". Once saved, the code will automatically run and will start working.

Editing Code

You'll want to use the Mu python editor to modify the code. Mu is a simple code editor that works with the Adafruit CircuitPython boards. It's written in Python and works on Windows, MacOS, Linux and Raspberry Pi. The serial console is built right in so you get immediate feedback from your board's serial output! See the guide below to for download and setup instructions.

Circuit Playground Christmas Tree Code

import time
import board
import neopixel

# On CircuitPlayground Express, and boards with built in status NeoPixel -> board.NEOPIXEL
# Otherwise choose an open pin connected to the Data In of the NeoPixel strip, i.e. board.D1
pixel_pin = board.NEOPIXEL

# On a Raspberry pi, use this instead, not all pins are supported
# pixel_pin = board.D18

# The number of NeoPixels
num_pixels = 10

# Increase or decrease between 0 and 1 to increase or decrease the brightness of the LEDs
brightness = 0.6

# The order of the pixel colors - RGB or GRB. Some NeoPixels have red and green reversed!
# For RGBW NeoPixels, simply change the ORDER to RGBW or GRBW.
ORDER = neopixel.GRB

pixels = neopixel.NeoPixel(pixel_pin, num_pixels, brightness=brightness, auto_write=False,
                           pixel_order=ORDER)


def wheel(pos):
    # Input a value 0 to 255 to get a color value.
    # The colours are a transition r - g - b - back to r.
    if pos < 0 or pos > 255:
        r = g = b = 0
    elif pos < 85:
        r = int(pos * 3)
        g = int(255 - pos * 3)
        b = 0
    elif pos < 170:
        pos -= 85
        r = int(255 - pos * 3)
        g = 0
        b = int(pos * 3)
    else:
        pos -= 170
        r = 0
        g = int(pos * 3)
        b = int(255 - pos * 3)
    return (r, g, b) if ORDER in (neopixel.RGB, neopixel.GRB) else (r, g, b, 0)


def rainbow_swirl(wait):
    for j in range(255):
        for i in range(num_pixels):
            pixel_index = (i * 256 // num_pixels) + j
            pixels[i] = wheel(pixel_index & 255)
        pixels.show()
        time.sleep(wait)


def rainbow_fill(wait):
    for j in range(255):
        for i in range(num_pixels):
            pixel_index = int(i + j)
            pixels[i] = wheel(pixel_index & 255)
        pixels.show()
        time.sleep(wait)


def christmas_flash(duration):
    pixels.fill((255, 0, 0))
    pixels.show()
    time.sleep(duration)
    pixels.fill((255, 255, 255))
    pixels.show()
    time.sleep(duration)


while True:
    for _ in range(5):
        christmas_flash(0.5)

    for _ in range(5):
        christmas_flash(0.1)

    pixels.fill((255, 0, 0))
    pixels.show()
    time.sleep(1)

    rainbow_fill(0.001)  # Increase the number to slow down the rainbow

    pixels.fill((0, 0, 0))
    pixels.show()
    time.sleep(1)
    rainbow_swirl(0.001)  # Increase the number to slow down the rainbow

This guide was first published on Dec 19, 2018. It was last updated on Dec 19, 2018.

This page (Software) was last updated on Nov 04, 2020.

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