Python program to communicate with a microbit

microbit_zerogui_example.py

from guizero import *

import serial
from serial.serialutil import SerialException
from serial.tools import list_ports

def connect():
    try:
        ser.open()
        ser.write("from microbit import * \r".encode())
    except SerialException:
        alerts.error(app, "No Connection! Unplug microbit and try again")

def disconnect():
    ser.close()

""" send_data() function
run when send_button is clicked. Gets data from faces_to_send_list
and writes to serial port as bytes

1. .get selected face from faces_to_send_list
2. convert to bytes
3. .write to serial port

Alternatively, 1 + 2 + 3 all on the same line:
ser.write((faces_to_send_list.get() + '\r').encode())
"""

def send_data():
    command_to_send = faces_to_send_list.get() + '\r'
    command_to_send_bytes = command_to_send.encode()
    try:
        ser.write(command_to_send_bytes)
    except SerialException:
        alerts.error(app, "Could not Send. Connected?")

""" find_microbit_comport() function
returns COM port / device the microbit is attached to.

For each com port on the computer, check whether the
attached device's product ID and vendor ID match
the microbit's.
"""

def find_microbit_comport():
    ports = list(list_ports.comports())
    for p in ports:
        if (p.pid == 516) and (p.vid == 3368): 
            return str(p.device)
        
""" Main Program """

ser = serial.Serial()
ser.baudrate = 115200
ser.port = find_microbit_comport()


# Window setup
app = App(layout='grid',
          height='300',
          width='200',
          title="Python Microbit Smile")

# button_box and its elements
button_box = Box(app, grid=[0, 0])

connect_button = PushButton(button_box,
                            text="Connect",
                            command=connect,
                            padx=3,
                            pady=3)

disconnect_button = PushButton(button_box,
                               text="Disconnect", 
                               command=disconnect,
                               padx=3,
                               pady=3)

# faces box and its elements

face_box = Box(app, grid=[0, 1])

faces_to_send_list = ButtonGroup(face_box, [
                ["Happy", "display.show(Image.HAPPY)"],
                ["Sad", "display.show(Image.SAD)"],
                ["Silly", "display.show(Image.SILLY)"],
                ["Yes", "display.show(Image.YES)"],
                ["No", "display.show(Image.NO)"],
                ["Pacman", "display.show(Image.PACMAN)"],
                ["Cow", "display.show(Image.COW)"]
                ],
                "display.show(Image.HAPPY)"
                )

send_button = PushButton(face_box,
                         text="Send",
                         command=send_data)

# render app window
app.display()