Programming

This guide shows how to install Circuit Python on the Circuit Playground Express. The example code provided below is by Phillip Burgess in the Jack-O-Lantern project.

Install CircuitPython

The Adafruit Circuit Playground Express ships with CircuitPython but lets go ahead and update it to the latest version. It's super easy with the circuitpython.org website, just click the link below to launch the page. There you can choose to install stable release or beta. 

Quick Start

  • Connect board to computer via a known good USB and double press the reset button.
  • Download circuitpython UF2 and upload to the CIRCUITBOOT drive.
  • Open CIRCUITPY drive and upload the required libraries (listed below) and code.py

Adafruit Circuit Python Libraries

Download the Circuit Python library bundle and unzip the folder. Create a new folder in the CIRCUITPY drive and name it "lib". The following libraries are required to run the code properly. Double check to ensure all of the files and folders are inside the lib folder on the CIRCUITPY drive.

  • neopixel.mpy

Demo Code

In this project we utilized the Jack-O-Lantern Pumpkin code as is, but you can modify the color and brightness if you wish.

"""Jack-o'-Lantern flame example Adafruit Circuit Playground Express"""

import math
import board
import neopixel
try:
    import urandom as random  # for v1.0 API support
except ImportError:
    import random

NUMPIX = 10        # Number of NeoPixels
PIXPIN = board.D8  # Pin where NeoPixels are connected
STRIP = neopixel.NeoPixel(PIXPIN, NUMPIX, brightness=1.0)
PREV = 128

def split(first, second, offset):
    """
    Subdivide a brightness range, introducing a random offset in middle,
    then call recursively with smaller offsets along the way.
    @param1 first:  Initial brightness value.
    @param1 second: Ending brightness value.
    @param1 offset: Midpoint offset range is +/- this amount max.
    """
    if offset != 0:
        mid = ((first + second + 1) / 2 + random.randint(-offset, offset))
        offset = int(offset / 2)
        split(first, mid, offset)
        split(mid, second, offset)
    else:
        level = math.pow(first / 255.0, 2.7) * 255.0 + 0.5
        STRIP.fill((int(level), int(level / 8), int(level / 48)))
        STRIP.write()

while True:  # Loop forever...
    LVL = random.randint(64, 191)
    split(PREV, LVL, 32)
    PREV = LVL

More Projects!

Check out these projects below, they're all using Circuit Playground express.

Project Examples

This guide was first published on Apr 30, 2019. It was last updated on Apr 30, 2019.

This page (Code) was last updated on Feb 16, 2021.

Text editor powered by tinymce.