Timer does not hop to default value or next interval

Question

In following code. the code does run al individual lines. the Interval 1 line wil run between 21.00 and 21.05hr the Interval 2 line wil run between 22.00 and 22.05hr The standard pulse line wil run on al other timeframes.

Problem: the code does i.e. not hop from interval 1 -> standard pulse -> interval 2 etc. it keeps running the timeframe when the code started to run.

Can someone help me with this python time issue?

This is the code:

from __future__ import division
from datetime import datetime, time

# Import the PCA9685 module.
import Adafruit_PCA9685

now = datetime.now()

# Initialise the PWM device using the default address
pwm = Adafruit_PCA9685.PCA9685()
# Note if you'd like more debug output you can instead run:
#pwm = PWM(0x40, debug=True)

servo_min = 300  # Min pulse length out of 4096
servo_max = 600  # Max pulse length out of 4096

def setServoPulse(channel, pulse):
  pulseLength = 1000000                   # 1,000,000 us per second
  pulseLength /= 60                       # 60 Hz
  print "%d us per period" % pulseLength
  pulseLength /= 4096                     # 12 bits of resolution
  print "%d us per bit" % pulseLength
  pulse *= 1000
  pulse /= pulseLength
  pwm.set_pwm(channel, 0, pulse)

# Set frequency to 60hz, good for servos.
pwm.set_pwm_freq(60)

while True:
    if now.time() >= time(21, 00, 00) and now.time() <= time(21, 05, 0):
        print "Interval 1"
        pwm.set_pwm(0, 0, servo_min)
    elif now.time() >= time(22, 00, 0) and now.time() <= time(22, 05, 0):
        print "Interval 2"
        pwm.set_pwm(0, 0, servo_min)
    else:
       print "Standard pulse"
       pwm.set_pwm(0, 0, servo_max)

Answer 1

By the documentation, datetime.now() returns current time, so in now variable is always stored only time you started your program. Try putting now = datetime.now() atop in your while loop.

...
# Set frequency to 60hz, good for servos.
pwm.set_pwm_freq(60)

while True:
    now = datetime.now()
    if now.time() >= time(21, 00, 00) and now.time() <= time(21, 05, 0):
        print "Interval 1"
        pwm.set_pwm(0, 0, servo_min)
    elif now.time() >= time(22, 00, 0) and now.time() <= time(22, 05, 0):
        print "Interval 2"
        pwm.set_pwm(0, 0, servo_min)
    else:
        print "Standard pulse"
        pwm.set_pwm(0, 0, servo_max)