Raspberry Pi Filesystem Activity Fading LED indicator

# Raspberry Pi Filesystem Activity Fading LED indicator
# by pyroxide (pyroxi.de)
#
# RPi.GPIO as well as psutil is required
#
# Both may be installed using pip:
# $ sudo pip install RPi.GPIO
# $ sudo pip install psutil
#
# or manually:
# RPi.GPIO: https://aur.archlinux.org/packages/python-raspberry-gpio/
# psutil: https://pypi.python.org/pypi/psutil/#downloads
import RPi.GPIO as GPIO
import time, psutil

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

sleepTime = 0.01 #length of time between activity checks
hddled = 3 # hdd activity led GPIO pin number
dbg = True # debug messages
increment = 2
rampingIncrement = 4

GPIO.setup(hddled, GPIO.OUT)
led = GPIO.PWM(hddled,100)
value = 0
lastValue = 0
led.start(value)
oldact = psutil.disk_io_counters()
ramping = False
try:
    while (True):
        newact = psutil.disk_io_counters()
        if (ramping):
            value += rampingIncrement
            ramping = (value < 100)
            if ((dbg) and (not ramping)):
                print("ramping=",ramping)
        elif ((newact.read_count > oldact.read_count) or (newact.write_count > oldact.write_count)):
            value = 24
            ramping = True
            if (dbg):
                print("ramping=",ramping)
        else:
            value = max(0,value-increment)
        led.ChangeDutyCycle(max(min(value,100),0))
        if ((dbg) and (value != lastValue)):
            print("value=",value)
        oldact = newact
        time.sleep(sleepTime)

except KeyboardInterrupt:
    led.stop()
    GPIO.cleanup()