import RPi.GPIO as GPIO
import time
from smbus import SMBus
bus = SMBus(1)
an0 = 0
led1 = 23
led2 = 22
led3 = 25
GPIO.setwarnings(False)
GPIO.setmode(GPIO.BCM)
GPIO.setup(led1,GPIO.OUT)
GPIO.setup(led2,GPIO.OUT)
GPIO.setup(led3,GPIO.OUT)
GPIO.output(led1,GPIO.LOW)
GPIO.output(led2,GPIO.LOW)
GPIO.output(led3,GPIO.LOW)

def read_ain(i):    
    global bus
    bus.write_byte(0x48, i)
    bus.read_byte(0x48)
    return bus.read_byte(0x48)
print "CTRL+C = STOP program"
try:
    while True:
        an0 = read_ain(0)
        val = 160 - an0 # PULL UP on 3.3V
        ledv = val + 70 # > 150 turn LED ON  (50%)       
        print str(an0)+" - "+str(val)
        print "-"
        bus.write_byte_data(0x48, 0x40, ledv) # analog LED     
        if val > 30 and val < 70:
            GPIO.output(led1,GPIO.HIGH)
        else:
            GPIO.output(led1,GPIO.LOW)
        if val > 69 and val < 110:
            GPIO.output(led2,GPIO.HIGH)
        else:
            GPIO.output(led2,GPIO.LOW)
        if val > 109:
            GPIO.output(led3,GPIO.HIGH)
        else:
            GPIO.output(led3,GPIO.LOW)             
except KeyboardInterrupt:
    GPIO.cleanup()  # must be executed before program stop