/[svn.andrew.net.au]/scripts/read-temperature.py
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Revision 24 - (hide annotations)
Thu Jun 14 04:16:40 2007 UTC (15 years, 6 months ago) by apollock
File MIME type: text/x-python
File size: 3104 byte(s)
Actually exit if the serial module is unavailable

1 apollock 18 #!/usr/bin/python
2    
3     ###
4     # Program to read the temperature from a DLP-TEMP-G from a Linux computer
5     # http://www.dlpdesign.com/usb/temp.shtml
6     #
7     # Loosely based on Tim Jensen's program at
8     # http://www.jensens.org/tim/read-temperature.txt
9     #
10     # Copyright (c) 2007 Andrew Pollock <me@andrew.net.au>
11     #
12     # This program is free software; you can redistribute it and/or modify
13     # it under the terms of the GNU General Public License as published by
14     # the Free Software Foundation; either version 2 of the License.
15     #
16     # This program is distributed in the hope that it will be useful,
17     # but WITHOUT ANY WARRANTY; without even the implied warranty of
18     # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
19     # GNU General Public License for more details.
20     #
21     # You should have received a copy of the GNU General Public License along
22     # with this program; if not, write to the Free Software Foundation, Inc.,
23     # 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
24     #
25    
26 apollock 24 import sys
27 apollock 18 try:
28     import serial
29     except ImportError:
30     print "This program requires pyserial,", \
31     "try checking the python-serial package is installed"
32 apollock 24 sys.exit(-1)
33 apollock 18
34     from optparse import OptionParser
35    
36 apollock 23 def read_temperature(device, sensor):
37     ser = serial.Serial(device, 9600, timeout=1)
38    
39     ser.write(SENSOR_QUERY_CMD[sensor])
40     buf = ser.read(8)
41     ser.close()
42    
43     temp = ord(buf[0]) | (ord(buf[1]) << 8)
44     return temp
45    
46    
47 apollock 18 SENSOR_QUERY_CMD = (None, 'S', 'T', 'U')
48     USAGE = "usage: %prog [options] [action]"
49    
50     parser = OptionParser(USAGE)
51     parser.add_option("-F", "--fahrenheit", action="store_false",
52     dest="use_celsius", help="Output temperature in degrees Fahrenheit",
53     default=False)
54     parser.add_option("-C", "--celsius", action="store_true",
55     dest="use_celsius", help="Output temperature in degrees Celsius",
56     default=True)
57     parser.add_option("-d", "--device", action="store", type="string",
58     dest="device", help="device to communicate with",
59     default="/dev/ttyUSB0")
60     parser.add_option("-s", "--sensor", action="store", type="int",
61     dest="sensor", help="sensor to query",
62     default="1")
63     parser.add_option("--mrtg", action="store_true",
64     dest="output_mrtg", help="Output decimal value suitable for MRTG",
65     default=False)
66     (options, args) = parser.parse_args()
67    
68     if not(options.sensor > 0 and options.sensor <= len(SENSOR_QUERY_CMD) - 1):
69     parser.error("Invalid sensor")
70    
71 apollock 22 try:
72 apollock 23 temp = read_temperature(options.device, options.sensor)
73 apollock 22 except serial.SerialException, e:
74     print "%s" % (e)
75     sys.exit(1)
76 apollock 18
77 apollock 23 degrees = temp / 16.0
78 apollock 18
79 apollock 23 # The power-up temperature of the sensor is 85 degrees, which is fairly unlikely
80     # So if we get that temperature, try reading it again
81 apollock 18
82 apollock 23 if degrees == 85.0:
83     try:
84     temp = read_temperature(options.device, options.sensor)
85     except serial.SerialException, e:
86     print "%s" % (e)
87     sys.exit(1)
88     degrees = temp / 16.0
89 apollock 18
90     if (options.use_celsius):
91     if (options.output_mrtg):
92     print "%.0f" % degrees
93     else:
94     print "%.4f degrees Celsius" % degrees
95     else:
96     degrees = (9.0/5.0) * degrees + 32.0
97     if (options.output_mrtg):
98     print "%.0f" % degrees
99     else:
100     print "%.4f degrees Fahrenheit" % degrees

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