Paul Hubbard pfh@phfactor.net
Dec 7 2011

This project is an evolution of the 'office-weather' project:

http://github.com/phubbard/arduino-buildbot

You can see the data at

https://pachube.com/feeds/22374

This version is a simplification - removing the buildbot hooks,
and planning on adding an external sensor node via Xbee. 

Think 'simple indoor-outdoor weather station', only over engineered, less reliable and more fun to hack.

Hardware requirements:
* Arduino
  http://arduino.cc/ or many other sources
* Ethernet shield
  http://www.sparkfun.com/products/9026  
* Dallas Semiconductor DS18B20 precision digital temperature sensor.
  http://www.sparkfun.com/products/245 
* Sparkfun TEMT6000 light sensor eval board
  http://www.sparkfun.com/products/8688
 * Ohmic Instruments SC-600 humidity sensor and signal conditioning module.
  http://www.ohmicinstruments.com/pdf/SC-600.pdf
  About $15, quite cheap for a sensor this nice. You need an external RC
  lowpass, so two more components in the circuit. See the PDF.
* Optional mini breadboard
  http://www.sparkfun.com/products/8800

Service requirements:
* Pachube account

Software requirements:
* Arduino plus OneWire library

Current status and functionality:
* Poll the hardware and pushes an update to Pachube
* Converts temp to floating point
  -reads humidity
  -corrects humidity for temperature
  -reads raw light value
* I had reliability problems with Ethernet and Zigbee, so the current code uses a server-side python app and USB.

Notes:
* Generating the payload for Pachube was a bit tricky.
* Pachube API in separate file, going to move feed ID to config.ini

To-do:
* Solar-power Arduino in watertight enclosure.
* Need to calibrate light sensor and correct for temperature