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mirror of https://github.com/skaringa/water-counter.git synced 2024-11-24 18:34:23 +01:00
water-counter/wairc.py
2016-03-28 17:54:40 +02:00

123 lines
3.5 KiB
Python
Executable File

#!/usr/bin/python -u
#
# emeir.py
#
# Program to read the electrical meter using a reflective light sensor
# This is the data recording part running on a Raspberry Pi.
# It retrieves data from the Arduino over USB serial and stores
# counter and consumption values into a round robin database.
# Copyright 2015 Martin Kompf
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program. If not, see <http://www.gnu.org/licenses/>.
import time
import sys
import os
import re
import select
import argparse
import rrdtool
# GPIO pin to read from
gpio_pin = 9
# counter unit: 1 revolution = x m^3
trigger_step = 0.001
# Path to RRD with counter values
count_rrd = "%s/water.rrd" % (os.path.dirname(os.path.abspath(__file__)))
# Create the Round Robin Database
def create_rrd():
print 'Creating RRD: ' + count_rrd
# Create RRD to store counter and consumption:
# Counter is GAUGE (m^3)
# Consumption is ABSOLUTE (m^3/s)
# 1 value per minute for 3 days
# 1 value per day for 30 days
# 1 value per week for 10 years
# Consolidation LAST for counter
# Consolidation AVERAGE for consumption
try:
rrdtool.create(count_rrd,
'--no-overwrite',
'--step', '60',
'DS:counter:GAUGE:86400:0:1000000',
'DS:consum:ABSOLUTE:86400:0:1000000',
'RRA:LAST:0.5:1:4320',
'RRA:AVERAGE:0.5:1:4320',
'RRA:LAST:0.5:1440:30',
'RRA:AVERAGE:0.5:1440:30',
'RRA:LAST:0.5:10080:520',
'RRA:AVERAGE:0.5:10080:520')
except Exception as e:
print 'Error ' + str(e)
# Get the last counter value from the rrd database
def last_rrd_count():
val = 0.0
handle = os.popen("rrdtool lastupdate " + count_rrd)
for line in handle:
m = re.match(r"^[0-9]*: ([0-9.]*) [0-9.]*", line)
if m:
val = float(m.group(1))
break
handle.close()
return val
# Setup gpio edge interrupt triggering
def setup_gpio(pin):
os.system("gpio export {} in".format(pin))
os.system("gpio edge {} rising".format(pin))
# Main
def main():
# Check command args
parser = argparse.ArgumentParser(description='Program to read the water meter using a reflective light sensor.')
parser.add_argument('-c', '--create', action='store_true', default=False, help='Create rrd database if necessary')
args = parser.parse_args()
if args.create:
create_rrd()
counter = last_rrd_count()
print "restoring counter to %f" % counter
# open gpio input value file
# and register handler for edge trigger
setup_gpio(gpio_pin)
f = open("/sys/class/gpio/gpio{}/value".format(gpio_pin), 'r')
epoll = select.epoll()
epoll.register(f, select.EPOLLIN | select.EPOLLET)
events = epoll.poll() # eat the first edge
while(1==1):
events = epoll.poll()
f.seek(0)
value = f.read(1)
if value == '1':
# trigger edge detected -> update count rrd
counter += trigger_step
update = "N:%.3f:%.3f" % (counter, trigger_step)
#print update
rrdtool.update(count_rrd, update)
f.close()
if __name__ == '__main__':
main()