If you haven't yet, visit the Circuit Playground Express introduction guide to learn about the CPX and how to install CircuitPython
Connect the Circuit Playground to your computer, copy the below code and save it as a file named code.py on your Circuit Playground's root directory.
This example has been updated for version 4+ of the CircuitPython HID library. On the CircuitPlayground Express this library is built into CircuitPython. So, please use the latest version of CircuitPython as well. (At least 5.0.0-beta.3)
# SPDX-FileCopyrightText: 2018 Collin Cunningham for Adafruit Industries
#
# SPDX-License-Identifier: MIT
# Big Control Alt Delete Board
# Code is written for the Circuit Playground Express board:
# https://www.adafruit.com/product/3333
# Needs the NeoPixel module installed:
# https://github.com/adafruit/Adafruit_CircuitPython_NeoPixel
# Author: Collin Cunningham
# License: MIT License (https://opensource.org/licenses/MIT)
import time
import board
import neopixel
import usb_hid
from adafruit_hid.keyboard import Keyboard
from adafruit_hid.keyboard_layout_us import KeyboardLayoutUS
from adafruit_hid.keycode import Keycode
from digitalio import DigitalInOut, Direction, Pull
pixels = neopixel.NeoPixel(board.NEOPIXEL, 10, brightness=.2)
pixels.fill((0, 0, 0))
pixels.show()
# The pins connected to each switch/button
buttonpins = [board.A7, board.A5, board.A3]
# The pins connected to each LED
ledpins = [board.A6, board.A4, board.A2]
# our array of button & LED objects
buttons = []
leds = []
# The keycode sent for each switch/button, will be paired with a control key
buttonkeys = [Keycode.CONTROL, Keycode.ALT, Keycode.DELETE]
buttonspressed = [False, False, False]
buttonspressedlast = [False, False, False]
# the keyboard object!
kbd = Keyboard(usb_hid.devices)
# we're americans :)
layout = KeyboardLayoutUS(kbd)
# make all button pin objects, make them inputs w/pullups
for pin in buttonpins:
button = DigitalInOut(pin)
button.direction = Direction.INPUT
button.pull = Pull.UP
buttons.append(button)
# make all LED objects, make them outputs
for pin in ledpins:
led = DigitalInOut(pin)
led.direction = Direction.OUTPUT
leds.append(led)
# set up the status LED
statusled = DigitalInOut(board.D13)
statusled.direction = Direction.OUTPUT
print("Waiting for button presses")
def pressbutton(index):
switch_led = leds[index] # find the switch LED
k = buttonkeys[index] # get the corresp. keycode/str
switch_led.value = True # turn on LED
kbd.press(k) # send keycode
def releasebutton(index):
switch_led = leds[index] # find the switch LED
k = buttonkeys[index] # get the corresp. keycode/str
switch_led.value = False # turn on LED
kbd.release(k) # send keycode
def lightneopixels():
vals = [0, 0, 0]
# if switch 0 pressed, show blue
if buttonspressed[0]:
vals[2] = 255
# if switch 1 pressed, show yellow
if buttonspressed[1]:
vals[0] = 127
vals[1] = 64
# if switch 2 pressed, show red
if buttonspressed[2]:
vals[0] = 255
# if all pressed, show white
if buttonspressed[0] and buttonspressed[1] and buttonspressed[2]:
vals = [255, 255, 255]
# if 0 & 1 pressed, show green
if buttonspressed[0] and buttonspressed[1] and not buttonspressed[2]:
vals = [0, 255, 0]
pixels.fill((vals[0], vals[1], vals[2]))
pixels.show()
while True:
# check each button
for button in buttons:
i = buttons.index(button)
if button.value is False: # button is pressed?
buttonspressed[i] = True # save pressed button
# was button not pressed last time?
if buttonspressedlast[i] is False:
print("Pressed #%d" % i)
pressbutton(i)
else:
buttonspressed[i] = False # button was not pressed
if buttonspressedlast[i] is True: # was button pressed last time?
print("Released #%d" % i)
releasebutton(i)
lightneopixels()
# save pressed buttons as pressed last
buttonspressedlast = list(buttonspressed)
time.sleep(0.01)
If everything worked correctly, pressing a switch should light its LED, change the color of the Circuit Playground's neopixels, and send a keyboard command out over USB to your computer. Additionally, pressing multiple switches simultaneously should mix each switch's color and display it on the Circuit Playground.
Page last edited January 20, 2025
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