1#!/usr/bin/python
2# Author: Zion Orent <zorent@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
24import time, sys, signal, atexit
25
26# Load alcohol sensor module
27import 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.
34myAlcoholSensor = upmMq303a.MQ303A(0, 15)
35
36
37## Exit handlers ##
38# This function stops python from printing a stacktrace when you hit control-C
39def SIGINTHandler(signum, frame):
40	raise SystemExit
41
42# This function lets you run code on exit, including functions from myAlcoholSensor
43def exitHandler():
44	print "Exiting"
45	sys.exit(0)
46
47# Register exit handlers
48atexit.register(exitHandler)
49signal.signal(signal.SIGINT, SIGINTHandler)
50
51
52print "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
56def warmup(iteration):
57	totalSeconds = (30 * iteration)
58	time.sleep(30)
59	print totalSeconds, "seconds have passed"
60warmup(1)
61warmup(2)
62warmup(3)
63warmup(4)
64
65notice = ("This sensor may need to warm "
66"until the value drops below about 450.")
67print notice
68
69# Print the detected alcohol value every second
70while(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