flame.py

import RPi.GPIO as GPIO
import time

DO_pin = 17
AO_pin = 0 #flame sensor AO connected to ADC chanannel 0
# change these as desired - they're the pins connected from the
# SPI port on the ADC to the Cobbler
SPICLK = 11
SPIMISO = 9
SPIMOSI = 10
SPICS = 8

#port init
def init():
          GPIO.setwarnings(False)
          GPIO.setmode(GPIO.BCM)
          #GPIO.output(buzzer,GPIO.HIGH)
          GPIO.setup(DO_pin,GPIO.IN,pull_up_down=GPIO.PUD_UP)
          # set up the SPI interface pins
          GPIO.setup(SPIMOSI, GPIO.OUT)
          GPIO.setup(SPIMISO, GPIO.IN)
          GPIO.setup(SPICLK, GPIO.OUT)
          GPIO.setup(SPICS, GPIO.OUT)
          pass

#read SPI data from MCP3008(or MCP3204) chip,8 possible adc's (0 thru 7)
def readadc(adcnum, clockpin, mosipin, misopin, cspin):
        if ((adcnum > 7) or (adcnum < 0)):
                return -1
        GPIO.output(cspin, True)  

        GPIO.output(clockpin, False)  # start clock low
        GPIO.output(cspin, False)     # bring CS low

        commandout = adcnum
        commandout |= 0x18  # start bit + single-ended bit
        commandout <<= 3    # we only need to send 5 bits here
        for i in range(5):
                if (commandout & 0x80):
                        GPIO.output(mosipin, True)
                else:
                        GPIO.output(mosipin, False)
                commandout <<= 1
                GPIO.output(clockpin, True)
                GPIO.output(clockpin, False)

        adcout = 0
        # read in one empty bit, one null bit and 10 ADC bits
        for i in range(12):
                GPIO.output(clockpin, True)
                GPIO.output(clockpin, False)
                adcout <<= 1
                if (GPIO.input(misopin)):
                        adcout |= 0x1

        GPIO.output(cspin, True)
        
        adcout >>= 1       # first bit is 'null' so drop it
        return adcout

def main():
         init()
         time.sleep(2)
         print"will detect sonud and light signal"
         while True:
                  flame_value = readadc(AO_pin, SPICLK, SPIMOSI, SPIMISO, SPICS)
                  if GPIO.input(DO_pin)==False:
                            print"***********"
                            print"* Saft! *"
                            print' '
                            time.sleep(0.5)
                  else:
                            print"***********"
                            print"* Fire! *"
                            print "fire ADC value is: " + str("%.1f"%((1024-flame_value)/1024.*3.3))+"V"
                            print"***********"
                            print' '  
                            time.sleep(0.5)
                  
                           
        

if __name__ =='__main__':
         try:
                  main()
         except KeyboardInterrupt:
                  pass
GPIO.cleanup()