ds18b20.py

#!/usr/bin/env python

import glob
import time
import re
import RPi.GPIO as GPIO
import subprocess
import MySQLdb as sql
import pushover
from Rules import Rules

# Determine location of first found DS18B20 sensor 
base_dir = '/sys/bus/w1/devices/'
device_folder = glob.glob( base_dir + '28*' )[0]
device_file = device_folder + '/w1_slave'

# Configure GPIO
GPIO.setmode( GPIO.BCM )
GPIO.setwarnings( False )

# Setup Rules
rf = Rules( 'localhost', 'rpi', 'rpi', 'sensordata' )

# Log data to the MySQL database
def logData( id, value):
    try:
        # Insert new data
        cur.execute( "insert into sensor_data(sensor_id,value) values( {0}, {1} )".format( id, value ) )
        # Save changes
        con.commit()
        return
    except:
        if con:
            con.rollback()
        return

# Controle state for LED pin (turn on/off the connected LED)
def ledMode( PiPin, mode ):
    GPIO.setup( PiPin, GPIO.OUT )
    GPIO.output( PiPin, mode )
    return

# Read data from the raw device
def read_temp_raw():
    f = open( device_file, 'r' )
    lines = f.readlines()
    f.close()
    return lines

# Get data from Raspberry Pi internal sensors
def read_rpi():
    # Read CPU temperature
    rpiCPU = float( open( '/sys/class/thermal/thermal_zone0/temp' ).read() ) / 1000.0
    logData( 4, rpiCPU )

    # Read GPU temperature
    output = subprocess.check_output(["/opt/vc/bin/vcgencmd", "measure_temp"])
    rpiGPU = float( output.split( '=' )[1][:-3] )
    logData( 5, rpiGPU )
    return

# Determine temperature and humidity from the DHT22/AM2302 sensor
def read_dht22( PiPin ):
    output = subprocess.check_output( ["/usr/bin/nice", "-20", "/home/pi/raspberrypi/Adafruit_DHT", "2302", str(PiPin)] )
    matches = re.search( "Temp =\s+([0-9.]+)", output )
    if ( matches ):
        logData( 2, float(matches.group( 1 ) ) )
    matches = re.search( "Hum =\s+([0-9.]+)", output )
    if ( matches ):
        logData( 3, float( matches.group( 1 ) ) )
    return

# Determine temperature from the DS18B20 sensor
def read_temp():
    lines = read_temp_raw()
    while lines[0].strip()[-3:] != 'YES':
        time.sleep( 0.2 )
        lines = read_temp_raw()
    equals_pos = lines[1].find( 't=' )
    if equals_pos != -1:
        temp_string = lines[1][equals_pos+2:]
        temp_c = float( temp_string ) / 1000.0
        return temp_c

# Turn off all LEDs
ledMode( 14, GPIO.LOW )
ledMode( 15, GPIO.LOW )
ledMode( 18, GPIO.LOW )

while True:
    # Connect to MySQL database
    con = sql.connect( host = "localhost", user = "rpi", passwd = "rpi", db = "sensordata" )
    cur = con.cursor()

    # Read internal sensors
    read_rpi()

    # Read DS18B20 (Temperature)
    temp_c = read_temp()
    logData( 1, temp_c )

    # Update LED based on temperature
    ledMode( 14, GPIO.HIGH if temp_c < 27 else GPIO.LOW )
    ledMode( 15, GPIO.HIGH if temp_c >= 27 and temp_c < 29 else GPIO.LOW )
    ledMode( 18, GPIO.HIGH if temp_c >= 29 else GPIO.LOW )

    # Read DHT22 (Temperature, Humidity)
    read_dht22( 22 )

    # Close MySQL connection
    con.close()

    # Run rule
    rf.run_rule( 1 )

    # Send notification
    if ( rf.getOutput() is not None ):
    	pushover.send_notification( rf.getDescription(), \
                                    rf.getOutput(), \
                                    "http://littlegemsoftware.com:314/chart-sensor.html", \
                                    "RPi Sensor Data" )

    # Execute shell command (if any)
    rf.runShellCmd()

    # Wait seconds for next collection
    time.sleep( 30 )