Wednesday, October 3, 2012

Raspberry Pi and Cosm


Over a month ago I decided to give Cosm.com a try instead of using my own MySQL database and graphing in Python. Since this was awhile ago I don't remember everything I did to get it working but I will post the code and libraries I am using that work.

Here is a simple library to making sending to Cosm easy.

http://www.netfluvia.org/layer8/?p=175

Here is the full code I am using to log the PIR sensor to Cosm, after the jump.


#!/usr/bin/python
#PIR LOGGING TO COSM

import RPi.GPIO as GPIO
import sys
import time
import datetime
from datetime import timedelta  
import cosm

API_KEY="API_KEY"
FEED_ID="FEED_ID"

def writeCosm(status):
 
 
 pfu = cosm.PachubeFeedUpdate(FEED_ID,API_KEY)
 pfu.addDatapoint("Pi",status)
 pfu.buildUpdate()
 pfu.sendUpdate()
 
 print "Uploaded Motion data to Cosm"
 
 return
 


ledPin = 17
pirPin = 18
motionCount = 0
timerMin = 1 #Number of minutes between database writes

GPIO.setmode(GPIO.BCM)
GPIO.setup(ledPin, GPIO.OUT)
GPIO.setup(pirPin, GPIO.IN)



loop = 1
while loop == 1 : 
 
 GPIO.output(ledPin, GPIO.HIGH)
 time.sleep(.5)
 GPIO.output(ledPin, GPIO.LOW)
 
 startTimer = datetime.datetime.utcnow() 
 #startTimer2 = startTimer
 
 while datetime.datetime.utcnow() < startTimer+timedelta(minutes=timerMin)  :
  
  #if datetime.datetime.utcnow() >= startTimer2+timedelta(milliseconds=600) :
  motionCount+=GPIO.input(pirPin)
  time.sleep(.60)
  #startTimer2 = datetime.datetime.utcnow()
 
 #motionCount = ((motionCount/500)*100)  
 writeCosm(motionCount)
 motionCount = 0
 
print "Done"

This should be a good example to get you started. There are other libraries but this seemed the simplest to use and most straightforward. I am not sure if this is what I will stick with but it works for now. Using the same example, I am also logging my Smart Outlet temperature and light sensors to Cosm via an Xbee connected to the UART. I find that the temperature is not accurate at all, even with averaging the ADC. I'll have to figure it out on another day.

RPi with Xbee Pro Series 1
The Xbee is using this adapter: http://www.digikey.com/product-detail/en/32403/32403PAR-ND/2696575


Comment below if you are using Cosm for your project, I would like to hear about it!


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