# Example Python Servo Script #2 – Calibrating Range
# The first script makes use of the Gpiozero defaults. It assumes the servo uses a signal frame width of 20ms.
# The pulse width for the minimum and maximum rotation is assumed to be 1ms and 2ms. This information should be
# available in the servo specification and I would avoid sellers that don’t provide this data.
# I found that with the default settings my servo only moved +45/-45 degrees. I changed the pulse width parameters
# in order to get a full 90 degrees of rotation in either direction .


from gpiozero import Servo
from time import sleep

myGPIO = 17

myCorrection = 0.45
maxPW = (2.0 + myCorrection) / 1000
minPW = (1.0 - myCorrection) / 1000

servo = Servo(myGPIO, min_pulse_width=minPW, max_pulse_width=maxPW)

while True:
    servo.mid()
    print("mid")
    sleep(0.5)
    servo.min()
    print("min")
    sleep(1)
    servo.mid()
    print("mid")
    sleep(0.5)
    servo.max()
    print("max")
    sleep(1)

# The servo should now move between its minimum, middle and maximum positions with a small delay in-between.
#
# In this example the min pulse width is decreased from the default of 1 by a correction of 0.45 to 0.55ms.
# The max pulse width is increased from the default of 2 by 0.45 to 2.45ms. This gave my servo a full 90 degrees
# of rotation in both directions. The values “0.55” and “2.45” are divided by 1000 to convert them to milliseconds.
#
# There is nothing magical about “0.45”. It was just the correction that worked best for my servo.
#
# To work out these numbers I started with :
#
# myCorrection=0
# maxPW=(2.0+myCorrection)/1000
# minPW=(1.0-myCorrection)/1000
#
# and increased/decreased the correction number in increments of 0.05. This allowed me to find the biggest change
# I could make before the servo sounded unhappy.
#
# “myCorrection” has to be a number between 0 and 1 but is unlikely to ever need to be 1!