RaspiWatt: discover power consumption using a Kill-A-Watt & Pi

Excellent info Drew. Thank you again. One more request/suggestion: it would be great to a have link that showed the parts needed to add additional monitors. Is it just the Xbee and Kill-a-watt devices, or is that tweet-a-watt starter pack required for each additional monitor or set of monitors? If the latter, could 1 starter pack plus two kill-a-watts be used for adding two more transmitting monitors? I've been wanting to build something like this for my house for a while. I'm looking forward to getting a better idea of where all my energy usage is going.

# Install system packages
cd ~/
mkdir dev
cd dev
sudo apt-get install git python-dev python-setuptools python-smbus i2c-tools python-pip

# Install RPi.GPIO module
sudo easy_install -U distribute
sudo pip install rpi.gpio

# Install EEML module (for Cosm)
wget -O geekman-python-eeml.tar.gz github.com/.../master
cd geekman-python-eeml*
sudo python setup.py install

# Active kernel modules for i2c (for LCD Pi Plate)
for Raspbian users, edit /etc/modules:
sudo nano /etc/modules

and add:
i2c-bcm2708 
i2c-dev

sudo i2cdetect -y 0 (if you are using a version 1 Raspberry Pi)
sudo i2cdetect -y 1 (if you are using a version 2 Raspberry Pi)      
This will search /dev/i2c-0 or /dev/i2c-1 for all address, and if an Adafruit LCD Plate is connected, it should show up at 0x20

# Install Adafruit library for LCD Pi Plate
git clone github.com/.../Adafruit-Raspberry-Pi-Python-Code.git
cd Adafruit-Raspberry-Pi-Python-Code
cd Adafruit_CharLCDPlate
sudo python Adafruit_CharLCDPlate.py
--------------
If you have a rev 2 (512MB) Pi, or if you're not getting anything displaying, it might be due to th I2C bus number change in the Pi hardware. Edit Adafruit_CharLCD.py using a command like "nano Adafruit_CharLCD.py" and change the line
lcd = Adafruit_CharLCDPlate(busnum = 0)
to
lcd = Adafruit_CharLCDPlate(busnum = 1)
--------------

# Install Tweet-a-Watt code modified for the RaspiWatt project
git clone github.com/.../Tweet-a-Watt.git
cd Tweet-a-Watt
PYTHON_PATH=$HOME/dev/Adafruit-Raspberry-Pi-Python-Code/Adafruit_CharLCDPlate sudo python wattcher_cosm.py

The following instructions to install the RaspiWatt software on the Raspberry Pi are based on these references:

Send Raspberry Pi Data to COSM: Necessary Packages

http://learn.adafruit.com/send-raspberry-pi-data-to-cosm/necessary-packages

Adafruit 16x2 Character LCD + Keypad for Raspberry Pi: Usage

Tweet-a-Watt software:

http://www.ladyada.net/make/tweetawatt/software.html

Yeah, it's just running ladyada's Tweet-A-Watt python code like the PC would have done in the original design.  It's been modified to do some new things like display data on the Pi Plate LCD.  The bigger change is going from ladyada's custom AppEngine webapp to Cosm for data logging and graphing.  The twitter code has also been removed since I didn't want it for this project (it could be added back in though based on ladyada's original code).

Awesome project. I'm interested in building this one. I already have a Pi and a Kill-a-Watt meter so I partway there. One question: is the Pi taking the place of the computer in Ladyada's schematic and able to receive info from multiple meters?

Thanks for posting this. I'm looking forward to the more detailed how-to posts.