gistfile1.py

#!/usr/bin/python
 
import sys,struct, argparse, time, os, signal
import tempfile

#Setup Variables
#Setup RGB Pins
pins = (27, 23, 18)
 
#Setup lock file for potential background work
lockfile = 'rgbled.lock'
temp_dir = tempfile.gettempdir()


if not temp_dir.endswith(os.sep):
   temp_dir = ''.join([temp_dir, os.sep])
lockfile = ''.join([temp_dir, lockfile])

description='Raspberry Pi RGB LED tool'
parser = argparse.ArgumentParser(description=description,
 epilog='--blink, --pulse, --keep and --delay are mutually exclusive')
 
parser.add_argument('rgbstr',action='store',nargs=1,
help='Desired LED Color in HEX format, ie: FFcc00',
metavar="RGBString")
 
parser.add_argument('-v','--verbose',action='store_true',help='Output verbose information')
 
group = parser.add_mutually_exclusive_group(required=False)
group.add_argument('-b','--blink',action='store',nargs=2,dest='blink',help='Blink the LED n times, d delay',metavar=("n","d"))
group.add_argument('-d','--delay',action='store',nargs=1,dest='delay',help='Show and hold the LED for a delay',metavar='d')
group.add_argument('-p','--pulse',action='store',nargs=1, dest='pulse',help='Pulse the led with a speed 0 - 5',metavar='s')
group.add_argument('-k','--keep',action='store_true',help='Keep the LED lit')

args = parser.parse_args()

def check_lock():
    if args.verbose is not False: print('[>] Checking for lockfile')
    if os.path.isfile(lockfile):
        if args.verbose is not False: print(' [+] Lockfile found')
        with open(lockfile, "rt") as f:
            if args.verbose is not False: print(' [+] Killing existing PID')
            try:
                os.kill(int(f.read().rstrip()), signal.SIGKILL)
            except:
                if args.verbose is not False: print(' [!] Already terminated')
        if args.verbose is not False: print(' [+] Deleting lockfile')
        os.remove(lockfile)
    else:
        if args.verbose is not False: print(' [-] No lockfile')
		
def set_lock():
    if args.verbose is not False: print('[>] Creating lockfile')
    with open(lockfile, "wt") as f:
        f.write(str(os.getpid()))

def setLED(rgbstr):
    for (i, value) in enumerate(struct.unpack('BBB',bytes.fromhex(rgbstr))):
        os.system('/bin/echo "{}={}" > /dev/pi-blaster'.format(pins[i],value/255))


def pulseLED(rgbstr, speed):
    rgb = ('r','g','b')
    orig_str = struct.unpack('BBB',bytes.fromhex(rgbstr))
    #max_step = int(max(orig_str)/step)
    speed = 1 if speed == 0 else speed
    max_step = int(100/speed) #For consistant timing
    lower_bound = .2 #Lower bound for LED pulsing
    try:
        while 1:
            for s in range(max_step):
                for (i, value) in enumerate(struct.unpack('BBB',bytes.fromhex(rgbstr))):
                    if (value-((value/max_step))) >= lower_bound:
                        os.system('/bin/echo "{}={}" > /dev/pi-blaster'.format(pins[i], ((value-((value/max_step)*s))/255)))
                    else:
                        #os.system('/bin/echo "{}={}" > /dev/pi-blaster'.format(pins[i],0))
                        pass #Turning off completely is jarring

            for s in reversed(range(max_step)):
                for (i, value) in enumerate(struct.unpack('BBB',bytes.fromhex(rgbstr))):
                    os.system('/bin/echo "{}={}" > /dev/pi-blaster'.format(pins[i], ((value-((value/max_step)*s))/255)))

    except (KeyboardInterrupt, SystemExit):
        setLED('000000')
        os.remove(lockfile)


check_lock()

#If we're going to be pulsing, we're going to write a lock file, with our PID in it
#If when the app launches, and we see a lockfile, we'll nuke the PID inside, and delete the file
if args.pulse is not None:
    set_lock()
    pulseLED(args.rgbstr[0], int(args.pulse[0]))
elif args.keep is not False:
    setLED(args.rgbstr[0])
elif args.blink is not None:
    #If 'blink' is not set, we're going to be blinking 1 time anyhow
    numFlashes = 1 if args.blink is None else int(args.blink[0])
    delay = args.delay[0] if args.blink is None else args.blink[1]
    for i in range(0,numFlashes):
       setLED(args.rgbstr[0])
       time.sleep(float(int(delay)/1000))
       setLED('000000')
       if i+1 != numFlashes:
            time.sleep(float(int(delay)/1000))