This is a controller for two linear actuators to a desk

RPI-desk-controller.py

from gpiozero import LED
from time import sleep

import sys

relay_a = LED("GPIO4")
relay_b = LED("GPIO17")
ht_file = "height.txt"
max_height = 400


def extend():
    print('Extending')
    relay_a.on()
    relay_b.off()


def retract():
    print('Retracting')
    relay_a.off()
    relay_b.on()


def stop():
    print('Stopping')
    relay_a.off()
    relay_b.off()


def write_height(height):
    if float(height) < 0:
        print('WARNING, height {0} is less than zero, reset recomended')
        height = 0
    if float(height) >= max_height:
        print(('WARNING: height' + str(height) + ' greater than max height (' +
               str(max_height) + '), reset recommended.'))
        height = max_height
    height_file = open(ht_file, 'w')
    height_file.write(str(height))
    height_file.close()


def read_height():
    height = '0'
    try:
        height_file = open(ht_file, 'r')
        height = height_file.read()
    except IOError:
        print('WARNING: height not known resetting')
        write_height(0)
    try:
        float_height = float(height)
    except:
        print('WARNING: height file corrupted. Reset recomended')
        float_height = 0
    return float_height


print('Argument height:', )

desired_height = float(sys.argv[1])

if desired_height > max_height:
    print('That is to high')
    exit()
current = read_height()
distance = desired_height - current
print(("distance to move:" + str(distance)))
if distance > 0:
    extend()
    sleep(abs(distance/10))
    write_height(read_height() + distance)
else:
    retract()
    sleep(abs(distance/10))
    write_height(read_height() + distance)

stop()