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      1 #!/usr/bin/python
      2 # Author: Zion Orent <zorent (at] ics.com>
      3 # Copyright (c) 2015 Intel Corporation.
      4 #
      5 # Permission is hereby granted, free of charge, to any person obtaining
      6 # a copy of this software and associated documentation files (the
      7 # "Software"), to deal in the Software without restriction, including
      8 # without limitation the rights to use, copy, modify, merge, publish,
      9 # distribute, sublicense, and/or sell copies of the Software, and to
     10 # permit persons to whom the Software is furnished to do so, subject to
     11 # the following conditions:
     12 #
     13 # The above copyright notice and this permission notice shall be
     14 # included in all copies or substantial portions of the Software.
     15 #
     16 # THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
     17 # EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
     18 # MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
     19 # NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
     20 # LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
     21 # OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
     22 # WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
     23 
     24 import time, sys, signal, atexit
     25 
     26 # Load alcohol sensor module
     27 import pyupm_mq303a as upmMq303a
     28 
     29 # Instantiate an mq303a sensor on analog pin A0
     30 # This device uses a heater powered from an analog I/O pin. 
     31 # If using A0 as the data pin, then you need to use A1, as the heater
     32 # pin (if using a grove mq303a).  For A1, we can use the D15 gpio, 
     33 # setup as an output, and drive it low to power the heater.
     34 myAlcoholSensor = upmMq303a.MQ303A(0, 15)
     35 
     36 
     37 ## Exit handlers ##
     38 # This function stops python from printing a stacktrace when you hit control-C
     39 def SIGINTHandler(signum, frame):
     40 	raise SystemExit
     41 
     42 # This function lets you run code on exit, including functions from myAlcoholSensor
     43 def exitHandler():
     44 	print "Exiting"
     45 	sys.exit(0)
     46 
     47 # Register exit handlers
     48 atexit.register(exitHandler)
     49 signal.signal(signal.SIGINT, SIGINTHandler)
     50 
     51 
     52 print "Enabling heater and waiting 2 minutes for warmup."
     53 
     54 # give time updates every 30 seconds until 2 minutes have passed
     55 # for the alcohol sensor to warm up
     56 def warmup(iteration):
     57 	totalSeconds = (30 * iteration)
     58 	time.sleep(30)
     59 	print totalSeconds, "seconds have passed"
     60 warmup(1)
     61 warmup(2)
     62 warmup(3)
     63 warmup(4)
     64 
     65 notice = ("This sensor may need to warm "
     66 "until the value drops below about 450.")
     67 print notice
     68 
     69 # Print the detected alcohol value every second
     70 while(1):
     71 	val = myAlcoholSensor.value()
     72 	msg = "Alcohol detected "
     73 	msg += "(higher means stronger alcohol): "
     74 	print msg + str(val)
     75 	time.sleep(1)
     76