SainSmart 5V USB Relay Module control script

sainsmart-relay-control.py

from pyftdi.ftdi import Ftdi
from sys import argv
from array import array
import re

if re.fullmatch(r'[\.x]{4}', argv[1]):
  relay_mask = sum([flag == 'x' and value or 0 for flag, value in zip(argv[1], [1, 2, 4, 8])])

  ftdi = Ftdi.create_from_url('ftdi:///1')
  ftdi.set_baudrate(9600)
  ftdi.set_bitmode(255, 1)
  ftdi.set_line_property(8, 1, 'N')
  ftdi.write_data(array('B', [relay_mask]))
else:
  print(f'Invalid pattern: {argv[1]}')