3_counter.py

import RPi.GPIO as GPIO
import time
#1
PINS = [7,15,16]
PIN_BTN = 19
COUNTER = 0
MAX_COUNT = 7
GPIO.setmode(GPIO.BOARD)


def Setup():
  #2
  GPIO.setup(PIN_BTN,GPIO.IN)
  for p in PINS:        
    GPIO.setup(p,GPIO.OUT)

def Display(bits):
  bits = bits.zfill(3)
  print "Displaying " + bits
  for i in range(len(bits)):
	GPIO.output(PINS[i],int(bits[i]))

def Count():
  global COUNTER
  #3
  if ( GPIO.input(PIN_BTN) == False):
      COUNTER += 1
      if ( COUNTER > MAX_COUNT ):
        COUNTER = 0    
      bin_number = bin(int(COUNTER))
      print "Sending the number " + str(COUNTER)
      time.sleep(0.500)
      Display(bin_number[2:])

def loop():  
  try:    
    while True:
      Count()
  except KeyboardInterrupt:
    pass
  finally:
    GPIO.cleanup()

Setup()

loop()