Circuitpython code accompanying https://editor.p5js.org/mjvo/sketches/JeV10d8kX

webserial_toggleLED.py

"""
Read the Serial port to receive color data for the neopixel.


This uses the optional second serial port available in Circuitpython 7.x
Activate it in the boot.py file with the following code

import usb_cdc
usb_cdc.enable(console=True, data=True)

Some boards might require disabling USB endpoints to enable the data port.
"""

import time
import board
import digitalio

import json
import usb_cdc

import keypad

################################################################
# select the serial Data port
################################################################

serial = usb_cdc.data

################################################################
# init bluefruit's onboard LED for visual indicator
# init bluefruit's button A for sending message
# replace with your own pins and stuff
################################################################


led = digitalio.DigitalInOut(board.LED)
led.switch_to_output()

btn = keypad.Keys((board.BUTTON_A,), value_when_pressed=True, pull=True)
# above used keypad library for debouncing
# see https://learn.adafruit.com/key-pad-matrix-scanning-in-circuitpython


while True:
    # read the secondary serial line by line when there's data
    # note that this assumes that the host always sends a full line, terminated by \n
    if serial.in_waiting > 0:
        data_in = serial.readline()
        # try to convert the data to a dict (with JSON)
        data = None
        if data_in:
            print(data_in)
            try:
                #data = data_in.decode()
                data = json.loads(data_in.decode())
            except ValueError:
                data = {"raw": data_in.decode()}

        # by using a dictionary, you can add any entry and data into it
        # to transmit any command you want and parse it here
        if isinstance(data, dict):
            # looks for key "toggle" in data dictionary
            if "toggle" in data:
                print(data["toggle"]) # log to local console
                led.value = data["toggle"] # toggle LED on and off
        # by using a dictionary, you can add any entry and data into it
        # to transmit any command you want and parse it here

    # this is where the rest of your code goes
    # if the code does a lot you don't need a call to sleep, but if possible
    # it's good to have the microcontroller sleep from time to time so it's
    # not constantly chugging
    
    event = btn.events.get()
    # event will be None if nothing has happened.
    if event:
        if event.pressed:
            print(event)
            msg = b"button A pressed\n"
            serial.write(msg)
    time.sleep(0.1)