import RPi.GPIO as GPIO
import time
import math

PHASE_DFREQ = 100
DRIVER_MIN = 0.3
DRIVER_MAX = 0.95

power = DRIVER_MIN

def phase_callback(channel):
global power
if power < DRIVER_MIN:
power = DRIVER_MIN
if power > DRIVER_MAX:
power = DRIVER_MAX

time.sleep(math.acos(2.0 * power - 1.0) / (math.pi * PHASE_DFREQ))
GPIO.output(23, GPIO.HIGH)
time.sleep(0.00003)
GPIO.output(23, GPIO.LOW)

GPIO.setmode(GPIO.BCM)
GPIO.setwarnings(False)

GPIO.setup(23, GPIO.OUT) # dimmer control
GPIO.setup(24, GPIO.IN) # phase control

GPIO.add_event_detect(24, GPIO.BOTH, callback=phase_callback, bouncetime=9)


try:
print(power)
time.sleep(15)

while True:
power += 0.05
print(power)
time.sleep(10)
except KeyboardInterrupt:
pass

finally:
GPIO.remove_event_detect(24)
GPIO.cleanup()