DS18B20 1-wire data collection on Raspberry Pi

create_config.py

#!/usr/bin/env python

import os, sys, glob, argparse
import ConfigParser

LOCATIONS = { 'rrd': ''
	    , 'graphs': ''
	    , 'sys_base': '/sys/bus/w1/devices/'
	    , 'config': ''
	    }
LOCATIONS['sys_devices'] = glob.glob(LOCATIONS['sys_base'] + '28*')

def main():
	global LOCATIONS
	parser = argparse.ArgumentParser(description='Generate config file for reading DS18B20 temperatures')

	parser.add_argument('-c', '--config'
						, action='store'
						, metavar='FILENAME'
						, required=True
						, help='Specifiy the configuration file to be used')

	parser.add_argument('-g', '--graphs'
						, action='store'
						, metavar='FILENAME'
						, required=True
						, help='Specifiy the directory to store the graph files in')

	parser.add_argument('-r', '--rrd'
						, action='store'
						, metavar='FILENAME'
						, required=True
						, help='Specifiy the RRD file to use')

	if len(sys.argv) == 1:
		parser.print_help()
		return

	args = parser.parse_args()
	
	LOCATIONS['config'] = args.config
	LOCATIONS['rrd'] = args.rrd
	LOCATIONS['graphs'] = args.graphs if args.graphs[-1:] == '/' else args.graphs + '/'

	config = ConfigParser.SafeConfigParser()

	config.add_section('locations')
	config.set('locations', 'graphs', LOCATIONS['graphs'])
	config.set('locations', 'rrd', LOCATIONS['rrd'])

	for index, sensor in enumerate(LOCATIONS['sys_devices']):
		config.add_section(str(sensor[-4:]))
		config.set(str(sensor[-4:]), 'ds', str('Temp Probe ' + sensor[-4:]))
		config.set(str(sensor[-4:]), 'colour', str('#' + sensor[-6:]))

	with open(LOCATIONS['config'], 'wb') as configfile:
		config.write(configfile)

	print 'Config file %s written', LOCATIONS['config']

	return

if __name__ == '__main__':
	main()

create_rrd.py

#!/usr/bin/env python

import os, sys, glob, argparse
import rrdtool
import ConfigParser

LOCATIONS = {}
SENSORS = {}

def read_config():
	global SENSORS
	global LOCATIONS

	config = ConfigParser.SafeConfigParser()
	config.read(LOCATIONS['config'])

	for s in config.sections():
		if s != 'locations':
			SENSORS[s] = {}
			for o in config.options(s):
				SENSORS[s][o] = config.get(s, o)
		else:
			for o in config.options(s):
				LOCATIONS[o] = config.get(s,o)

	return

def main():
	global LOCATIONS
	parser = argparse.ArgumentParser(description='Generate .rrd file for reading DS18B20 temperatures')

	parser.add_argument('-c', '--config'
						, action='store'
						, metavar='FILENAME'
						, required=True
						, help='Specifiy the configuration file to be used')

	if len(sys.argv) == 1:
		parser.print_help()
		return

	args = parser.parse_args()
	
	LOCATIONS['config'] = args.config

	read_config()

	data_sources = []

	for k, v in SENSORS.items():
		data_sources.append('DS:%s:GAUGE:600:U:U' % (v['ds']))

	rrdtool.create( LOCATIONS['rrd'], '--start', 'N', '--step', '300'
				  , data_sources
				  , 'RRA:AVERAGE:0.5:1:12'    #  1 hr,    5 min resolution
				  , 'RRA:AVERAGE:0.5:1:144'   # 12 hrs,   5 min resolution
				  , 'RRA:AVERAGE:0.5:1:288'   #  1 day,   5 min resolution
				  , 'RRA:AVERAGE:0.5:3:672'   #  7 days, 15 min resolution
				  , 'RRA:AVERAGE:0.5:12:720'  # 30 days,  1 hr  resolution
				  , 'RRA:AVERAGE:0.5:36:720'  # 90 days,  3 hr  resolution
				  , 'RRA:AVERAGE:0.5:288:365')#  1 year, 24 hr  resolution
	return

if __name__ == '__main__':
	main()

temps.cfg

[locations]
rrd=/pat/to/rrd_file.rrd
graphs=/path/to/graph_directory/

[9ce0]
ds = shed
colour = #FFCC00

[aab8]
ds = fridge
colour = #00CC00

[5cc3]
ds = freezer
colour = #0033FF

temps.py

#!/usr/bin/env python

import os, sys, datetime, re, glob, argparse
import rrdtool
import ConfigParser

LOCATIONS = { 'rrd': ''
	    , 'graphs': ''
	    , 'sys_base': '/sys/bus/w1/devices/'
	    , 'config': ''
	    }

LOCATIONS['sys_devices'] = glob.glob(LOCATIONS['sys_base'] + '28*')

SENSORS = {}

now = datetime.datetime.now()

def read_config():
	global SENSORS
	global LOCATIONS

	config = ConfigParser.SafeConfigParser()
	config.read(LOCATIONS['config'])

	for s in config.sections():
		if s != 'locations':
			SENSORS[s] = {}
			for o in config.options(s):
				SENSORS[s][o] = config.get(s,o)
			SENSORS[s]['value'] = 0
		else:
			for o in config.options(s):
				LOCATIONS[o] = config.get(s,o)			
                       LOCATIONS['graphs'] = LOCATIONS['graphs'] if LOCATIONS['graphs'][-1:] == '/' else LOCATIONS['graphs'] + '/'
	return


def graph_temps():

	GRAPH_DEFS = []
	LINE_DEFS = []

	# Common options for each graph, size, title, etc..
	GRAPH_OPTIONS = [ '--title', 'Temperatures'
					, '--vertical-label', 'Celcius'
					, '--width', '800'
					, '--height', '200'
					, '--slope-mode'
					, '--pango-markup'
					, '--imgformat', 'PNG'
					, '--watermark', "%s" % ( now.strftime('Updated: %c') )
					]

	# Header row for the legend and displayed measurements
	LEGEND_HEADER = [ 'COMMENT:\t'
					, 'COMMENT:\t<b>     Last</b>'
					, 'COMMENT:\t<b>Maximum</b>'
					, 'COMMENT:\t<b>Average</b>'
					, 'COMMENT:\t<b>Minimum</b>'
					, 'COMMENT:\t<b>95th %</b>\l'
					]

	# generate line and legend items for each DS in the .rrd
	for s, k in SENSORS.iteritems():
		GRAPH_DEFS.append('DEF:%s=%s:%s:AVERAGE' % (k['ds'], LOCATIONS['rrd'], k['ds']))
		LINE_DEFS.extend([
					  'LINE2:%s%s:<b>%s</b>' % (k['ds'], k['colour'], '{:<10}'.format(k['ds'].title()))
					, 'VDEF:%s_last=%s,LAST' % (k['ds'], k['ds'])
					, 'VDEF:%s_max=%s,MAXIMUM' % (k['ds'], k['ds'])
					, 'VDEF:%s_avg=%s,AVERAGE' % (k['ds'], k['ds'])
					, 'VDEF:%s_min=%s,MINIMUM' % (k['ds'], k['ds'])
					, 'VDEF:%s_pct=%s,95,PERCENT' % (k['ds'], k['ds'])
					, 'GPRINT:%s_last:\t%%6.2lf' % (k['ds'])
					, 'GPRINT:%s_max:\t%%6.2lf' % (k['ds'])
					, 'GPRINT:%s_avg:\t%%6.2lf' % (k['ds'])
					, 'GPRINT:%s_min:\t%%6.2lf' % (k['ds'])
					, 'GPRINT:%s_pct:\t%%6.2lf\l' % (k['ds'])
					])

	# Now we have all the parts to make an rrdgraph command
	# Loop through and generate a graphe for each period
	for schedule in ['hour', 'day', 'week', 'month', 'year']:
		ret = rrdtool.graph("%s%s.png" % ( LOCATIONS['graphs'], schedule )
							, '--start', 'end-1%s' % ( schedule[0] )
							, GRAPH_OPTIONS
							, GRAPH_DEFS
							, LEGEND_HEADER
							, LINE_DEFS, )
	return

def read_temps():
	# reads 1-wire DS18B20 temperature sensors and outputs options for rrdupdate
 
	global SENSORS
	DS_list = ""
	value_list = "N:"

	for index, sensor in enumerate(LOCATIONS['sys_devices']):
		for k, v in SENSORS.items():
			if sensor[-4:] == k:
				f = open(sensor + '/w1_slave', 'r')
				lines = f.readlines()
				f.close()
				if lines[0].strip()[-3:] == 'YES':
					v['value'] = float(lines[1][lines[1].find('t=')+2:])/1000.0
	return

def update_rrd():

	DS_list = ''
	value_list = 'N:'

	for k, v in SENSORS.items():
		DS_list += v['ds'] + ':'
		value_list += str(v['value']) + ':'

	DS_list = DS_list[:-1]
	value_list = value_list[:-1]

	rrdtool.update( LOCATIONS['rrd'], '--template', DS_list, value_list )

	return

def main():
	global LOCATIONS

	base, ext = os.path.splitext(__file__)

	parser = argparse.ArgumentParser(description='Read, store and graph temperatures from 1-wire sensors')
	parser.add_argument('-c', '--config', required=True, action='store', metavar='FILENAME', help="Specify config file to use.  * Required")
	parser.add_argument('-r', '--read', action='store_true', help="Read temperatures from sensors.  If --update is not specified rrd will not be updated and values will be printed to stdout")
	parser.add_argument('-u', '--update', action='store_true', help='Update rrd with values from sensors, implies --read.')
	parser.add_argument('-g', '--graph', action='store_true', help='Generate graphs from rrd values.  If --update is specified then graphs are generated *after* sensors are read')

	if len(sys.argv) == 1:
		parser.print_help()
		return

	args = parser.parse_args()

	LOCATIONS['config'] = args.config

	read_config()

	if args.update:
		args.read = True

	if args.read:
		read_temps()
		if not (args.update or args.graph):
			for k, v in SENSORS.items():
				print '%s:%s:%.3f' % (v['ds'], k, v['value'] )
		
	if args.update:
		update_rrd()

	if args.graph:
		graph_temps()		


if __name__ == '__main__':
	main()