Sending Raspberry Pi Sensor Updates to Xively

After I spent a few hours getting my Raspberry Pi sensors logging to Cosm, LogMeIn updated their site to Xively.  The way  updates are sent to the site using python also changed.  Parsing through Xively’s Raspberry Pi python example I managed to come up with a working script.  I have to admit it’s much more modular and handles errors more gracefully than my original Cosm script did.

#!/usr/bin/python

import os
import re
import xively
import subprocess
import time
import datetime
import sys

sys.path.append(‘/home/pi/python/Adafruit-Raspberry-Pi-Python-Code/Adafruit_BMP085’)

from Adafruit_BMP085 import BMP085

FEED_ID=xxxxxxxxxx
API_KEY=”xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx”
DEBUG=True

# initialize api client
api = xively.XivelyAPIClient(API_KEY)

# function to read temperature and pressure from bmp085
def read_bmp085():
if DEBUG:
print “reading bmp085 temperature and pressure”

bmp = BMP085(0x77)
temp = bmp.readTemperature()
pressure = bmp.readPressure()

temp = round(((9.0/5.0)*temp + 32), 2)
pressure = (pressure / 100)*0.0295301
pressure = round(pressure, 2)

if DEBUG:
print “bmp085 Temperature: %.2f F” % temp
print “Pressure: %.2f in.” % pressure

return {‘temp’:temp, ‘pressure’:pressure}

def read_dht():
if DEBUG:
print “reading dht temperature and humidity”

while True:
output = subprocess.check_output([“./Adafruit_DHT”, “2302”, “4”]);
if DEBUG:
print output

# search for humidity
matches = re.search(“Hum =\s+([0-9.]+)”, output)
if (matches):
humidity = float(matches.group(1))
if DEBUG:
print “Humidity: %.1f %%” % humidity

# search for temperature
matches = re.search(“Temp =\s+([0-9.]+)”, output)
if (matches):
temperature = float(matches.group(1))*(9.0/5.0) + 32
if DEBUG:
print “Temperature: %.1f F” % temperature
return {‘temperature’:temperature,’humidity’:humidity}

time.sleep(3)

# function to return a datastream object. This either creates a new datastream,
# or returns an existing one
def get_datastream(feed):
try:
temp_datastream = feed.datastreams.get(“temperature”)
if DEBUG:
print “Found existing temperature datastream”
except:
if DEBUG:
print “Creating new temperature datastream”
temp_datastream = feed.datastreams.create(“temperature”, tags=”temperature”)

try:
pressure_datastream = feed.datastreams.get(“pressure”)
if DEBUG:
print “Found existing pressure datastream”
except:
if DEBUG:
print “Creating new pressure datastream”
pressure_datastream = feed.datastreams.create(“pressure”, tags=”pressure”)

try:
humidity_datastream = feed.datastreams.get(“humidity”)
if DEBUG:
print “Found existing humidity datastream”
except:
if DEBUG:
print “Creating new humidity datastream”
humidity_datastream = feed.datastreams.create(“humidity”, tags=”humidity”)

return {‘tempds’:temp_datastream, ‘pressureds’:pressure_datastream, ‘humidityds’:humidity_datastream}
# main program entry point – runs continuously updating our datastreams with the
# with the current temperature, pressure, and humidity
def run():
print “Starting environmental monitoring script”

feed = api.feeds.get(FEED_ID)

datastreams = get_datastream(feed)

datastreams[‘tempds’].max_value = None
datastreams[‘tempds’].min_value = None
datastreams[‘pressureds’].max_value = None
datastreams[‘pressureds’].max_value = None
datastreams[‘humidityds’].min_value = None
datastreams[‘humidityds’].min_value = None

while True:
bmpdata = read_bmp085()
dhtdata = read_dht()

if DEBUG:
print “Updating Xively feed with temperature: %.2f F” % dhtdata[‘temperature’]
print “Updating Xively feed with pressure: %.2f in” % bmpdata[‘pressure’]
print “Updating Xively feed with humidity: %.2f percent” % dhtdata[‘humidity’]

datastreams[‘tempds’].current_value = dhtdata[‘temperature’]
datastreams[‘tempds’].at = datetime.datetime.utcnow()
datastreams[‘tempds’].update()

datastreams[‘pressureds’].current_value = bmpdata[‘pressure’]
datastreams[‘pressureds’].at = datetime.datetime.utcnow()
datastreams[‘pressureds’].update()

datastreams[‘humidityds’].current_value = dhtdata[‘humidity’]
datastreams[‘humidityds’].at = datetime.datetime.utcnow()
datastreams[‘humidityds’].update()

time.sleep(600)

run()