from gpiozero import Servo
from time import sleep

# https://gpiozero.readthedocs.io/en/stable/recipes.html#servo


#these pulse-width values come from the elektrobit product description
maxPW=2.1/1000
minPW=0.9/1000

# these values are empirically determined and represent maxima
# 0.3 will turn slow in one direction, -0.5 slow in the other
left = 1
right = -1
stop = -0.2

servo = Servo(
        17, 
        initial_value=None, 
        min_pulse_width=minPW, 
        max_pulse_width=maxPW)

while True:
    servo.value = left
    sleep(1)
    servo.value = right
    sleep(1)
    servo.value = stop
    sleep(2)