relay_test.py

import ftd2xx as ft
import time
import struct
import sys


ALL_OFF = b'\000'


list_of_devices = ft.listDevices()
for i, d in enumerate(list_of_devices):
    print('{}: {}'.format(i, d.decode()))
index = input('Select relay device: ')

try:
    relay_board_index = int(index)
except ValueError:
    print('Value Error: Not a valid relay.')
    sys.exit(1)

# open board and setup for Async BitBing Mode
try:
    my_relay = ft.open(relay_board_index)
except ft.DeviceError:
    print('Cannot open device: {}'.format(ft.DeviceError))
    sys.exit(2)

result = my_relay.setBitMode(0xFF, 0x1)
if not result:
    print('Setup successful.')
    details = ft.getDeviceInfoDetail()
    print('Description: {}'.format(details['description'].decode()))
else:
    print('Failed to setup relay. Exiting...')
    sys.exit(3)

delay = 1
for out in range(4):
    send = struct.pack('B', out)
    my_relay.write(send)
    time.sleep(delay)

time.sleep(5)
my_relay.write(ALL_OFF)

my_relay.close()