Code with CircuitPython

We'll be using CircuitPython for this project. Are you new to using CircuitPython? No worries, there is a full getting started guide here.

Adafruit suggests using the Mu editor to edit your code and have an interactive REPL in CircuitPython. You can learn about Mu and its installation in this tutorial.

Follow this guide for instructions on installing the latest release version of CircuitPython for the Feather M4 Express.

Libraries

You'll also need to add the following libraries for this project. Follow this guide on adding libraries. The ones you'll need are:

  • adafruit_neotrellis
  • adafruit_bus_device
  • adafruit_seesaw
  • neopixel

Download the latest adafruit-circuitpython-bundle .zip file as linked in the guide. Then,  unzip the file and drag those libraries to the lib folder on you Feather M4.

Code

Here is the code we'll use. Copy it and then paste in Mu. Save it to your Feather M4 as code.py

# Ambient Color Control Pad
# NeoTrellis to select colors of NeoPixel strip
# NeoTrellis connected to Feather M4 (need the extra memory vs. M0) SCL, SDA
# NeoPixel 120 strip connected to pin D5
# NeoPixel strip powered over 5V 2A DC wall power supply
# On/off button RGB connects En to GND, LED to D13

import time
import board
from board import SCL, SDA
import busio
import neopixel
from adafruit_neotrellis.neotrellis import NeoTrellis
from digitalio import DigitalInOut, Direction

button_LED = DigitalInOut(board.D13)
button_LED.direction = Direction.OUTPUT
button_LED.value = True

pixel_pin = board.D5
num_pixels = 120

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

# create the i2c object for the trellis
i2c_bus = busio.I2C(SCL, SDA)

# create the trellis object
trellis = NeoTrellis(i2c_bus)

# color definitions
OFF = (0, 0, 0)
RED = (255, 0, 0)
YELLOW = (255, 150, 0)
GREEN = (0, 255, 0)
YELLOW_GREEN = (127, 255, 0)
CYAN = (0, 255, 255)
LIGHT_BLUE = (0, 127, 255)
BLUE = (0, 0, 255)
PURPLE = (127, 0, 255)
ORANGE = (255, 80, 0)
PINK = (255, 0, 255)
ROUGE = (255, 0, 127)
WHITE = (100, 100, 100)
WHITE_WARM = (120, 100, 80)
WHITE_COOL = (80, 100, 120)
WHITE_GREEN = (80, 120, 100)


COLORS = [  # pixel colors
    RED, ORANGE, YELLOW, YELLOW_GREEN,
    GREEN, CYAN, LIGHT_BLUE, BLUE,
    PURPLE, PINK, ROUGE, WHITE,
    WHITE_WARM, WHITE_COOL, WHITE_GREEN, OFF
]

pixels.fill(COLORS[1])  # turn on the strip
pixels.show()


def dimmed_colors(color_values):
    (red_value, green_value, blue_value) = color_values
    return (red_value // 10, green_value // 10, blue_value // 10)


# this will be called when button events are received
def blink(event):
    # turn the trellis LED on when a rising edge is detected
    # do the chase for the NeoPixel strip
    if event.edge == NeoTrellis.EDGE_RISING:
        trellis.pixels[event.number] = dimmed_colors(COLORS[event.number])
        for chase_off in range(num_pixels):  # chase LEDs off
            pixels[chase_off] = (OFF)
            pixels.show()
            time.sleep(0.005)

        for chase_on in range(num_pixels - 1, -1, -1):  # chase LEDs on
            pixels[chase_on] = (COLORS[event.number])
            pixels.show()
            time.sleep(0.03)

    # turn the trellis LED back to full color when a rising edge is detected
    elif event.edge == NeoTrellis.EDGE_FALLING:
        trellis.pixels[event.number] = COLORS[event.number]


# boot up animation on trellis
trellis.pixels.brightness = 0.2
for i in range(16):
    # activate rising edge events on all keys
    trellis.activate_key(i, NeoTrellis.EDGE_RISING)
    # activate falling edge events on all keys
    trellis.activate_key(i, NeoTrellis.EDGE_FALLING)
    # set all keys to trigger the blink callback
    trellis.callbacks[i] = blink

    # light the trellis LEDs on startup
    trellis.pixels[i] = COLORS[i]
    time.sleep(.05)

print("  Ambient Color Control Pad")
print("    ---press a button to change the ambient color---")

while True:

    # call the sync function call any triggered callbacks
    trellis.sync()
    # the trellis can only be read every 17 milliseconds or so
    time.sleep(.02)
This guide was first published on Oct 27, 2018. It was last updated on Oct 27, 2018. This page (Code with CircuitPython) was last updated on Apr 23, 2019.