This project uses the LED animation rainbow example code from the CircuitPython LED Animation guide. The code is modified slightly to accommodate the additional pixels used in the sign.

Download the Adafruit CircuitPython Library Bundle

In order to run the code, we'll need to download a few libraries. Libraries contain code to help interface with hardware a lot easier for us.

Use the Adafruit M4 Express page on Installing Libraries to get the library that matches the major version of CircuitPython you are using noted above.

To run the code for this project, we need the three libraries in the Required Libraries list below. Unzip the library bundle and search for the libraries. Drag and drop the files into a folder named lib on the CIRCUITPY drive (which appears when your board is plugged into your computer via a known good USB cable) if the directory is not already on the Feather M4 Express).

Required Libraries 

  • neopixel.mpy
  • adafruit_led_animation

The Mu Python Editor

Mu is a simple Python editor that works with Adafruit CircuitPython hardware. 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! While you can use any text editor with your code, Mu makes it super simple. Instructions for Mu are available here.

Installing or upgrading CircuitPython

You should ensure you have CircuitPython 5.0 or greater on your board. Plug your board in with a known good data + power cable (not the cheesy USB cable that comes with USB power packs, they are power only). You should see a new flash drive pop up.

If the drive is CIRCUITPY, then open the boot_out.txt file to ensure the version number is 5.0 or greater. 

Download: file
Adafruit CircuitPython 5.3.1 on 2020-07-13; Adafruit Feather M4 Express with samd51j19

Click on the download link below to grab the project code directly from GitHub.

This example shows usage of the PixelMap helper to easily treat a single strip as a horizontal or
vertical grid for animation purposes.

For NeoPixel FeatherWing. Update pixel_pin and pixel_num to match your wiring if using
a different form of NeoPixels. Note that if you are using a number of pixels other than 32, you
will need to alter the PixelMap values as well for this example to work.

This example does not work on SAMD21 (M0) boards.
import board
import neopixel

from adafruit_led_animation.animation.comet import Comet
from adafruit_led_animation.animation.rainbowcomet import RainbowComet
from adafruit_led_animation.animation.rainbowchase import RainbowChase
from import Chase
from adafruit_led_animation.animation.rainbow import Rainbow
from adafruit_led_animation.sequence import AnimationSequence
from adafruit_led_animation import helper
from adafruit_led_animation.color import PURPLE, JADE, AMBER

# Update to match the pin connected to your NeoPixels
pixel_pin = board.D6
# Update to match the number of NeoPixels you have connected
pixel_num = 32

pixels = neopixel.NeoPixel(pixel_pin, pixel_num, brightness=0.5, auto_write=False)

pixel_wing_vertical = helper.PixelMap.vertical_lines(
    pixels, 8, 4, helper.horizontal_strip_gridmap(8, alternating=False)
pixel_wing_horizontal = helper.PixelMap.horizontal_lines(
    pixels, 8, 4, helper.horizontal_strip_gridmap(8, alternating=False)

comet_h = Comet(
    pixel_wing_horizontal, speed=0.1, color=PURPLE, tail_length=3, bounce=True
comet_v = Comet(pixel_wing_vertical, speed=0.1, color=AMBER, tail_length=6, bounce=True)
chase_h = Chase(pixel_wing_horizontal, speed=0.1, size=3, spacing=6, color=JADE)
rainbow_chase_v = RainbowChase(
    pixel_wing_vertical, speed=0.1, size=3, spacing=2, step=8
rainbow_comet_v = RainbowComet(
    pixel_wing_vertical, speed=0.1, tail_length=7, bounce=True
rainbow_v = Rainbow(pixel_wing_vertical, speed=0.1, period=2)
rainbow_chase_h = RainbowChase(pixel_wing_horizontal, speed=0.1, size=3, spacing=3)

animations = AnimationSequence(

while True:

Adjust Code

Look for the following lines in the code and adjust to fit the 8x8 NeoMatrix. Use any text editor or favorite IDE to modify the code. We suggest using Mu as noted above.

Download: file
# Update to match the pin connected to your NeoPixels
pixel_pin = board.D6
# Update to match the number of NeoPixels you have connected
pixel_num = 64

pixel_wing_vertical = helper.PixelMap.vertical_lines(
    pixels, 8, 8, helper.horizontal_strip_gridmap(8, alternating=False)
pixel_wing_horizontal = helper.PixelMap.horizontal_lines(
    pixels, 8, 8, helper.horizontal_strip_gridmap(8, alternating=False)

Upload Code

Ensure the file is named and drop it onto the CIRCUITPY drive main (root) directory that appears when your Feather is plugged into your computer via a known good USB data cable. The code will run properly when all of the files have been uploaded including libraries.

Customizing LED Animations

Take a moment to walk through the LED animation library for CircuitPython learn guide. The guide covers the how to create animations with horizontal and vertical grids.

This guide was first published on Aug 18, 2020. It was last updated on Aug 18, 2020.
This page (Code) was last updated on Oct 24, 2020.