Python to automatically select serial ports (for Arduino)

Question

Currently the python program must know which port a device (Arduino) is on before Python can communicate the device.

Problem: Whenever the device is

Answer 1

Using serial.tools.list_ports.comports, we can find and connect to an arduino with:

import warnings
import serial
import serial.tools.list_ports

arduino_ports = [
    p.device
    for p in serial.tools.list_ports.comports()
    if 'Arduino' in p.description  # may need tweaking to match new arduinos
]
if not arduino_ports:
    raise IOError("No Arduino found")
if len(arduino_ports) > 1:
    warnings.warn('Multiple Arduinos found - using the first')

ser = serial.Serial(arduino_ports[0])

If you know you're looking for exactly the same arduino each time, you can filter on p.serial_number instead

import serial.tools.list_ports

def find_arduino(serial_number):
    for pinfo in serial.tools.list_ports.comports():
        if pinfo.serial_number == serial_number:
            return serial.Serial(pinfo.device)
    raise IOError("Could not find an arduino - is it plugged in?")

ser = find_arduino(serial_number='85430353531351B09121')