Finished–Good Enough

Wiring to the Power Main

I finally got around to put in the current transformers  (CTs) in the panel last weekend. I had an electrician come and pull the meter out so I could install them. If you are wondering, I got permission from the utility company to do so. In hind-sight, I should have purchased split core transformers and just clip them on.

I can’t say much more about this, as it was quite a no brainer to do. This was the first time I tested  my Arduino with more than 13 amps and my only concern was if I was off in my scaling. Using commercial grade CT provide linear operation in the range I’m interested.


I took a utilitarian view in packaging the Ardiuno and circuitry and ended up using a dead router enclosure to host the solution. With limited tools, I cut out a place for the LCD and xbee radio.  It works and is out of the way so it met my simple requirements.


Collecting the Data

I can collect power related information as shown below and log it over time for trending purposes. I can also collect reactive and apparent power but for power factor tells me the story at a glance. As stated in an earlier post, I used Mango to do all that.  I was posting stuff on Pachube and exceeded the posts allowed for free so I disabled it. I will revisit this later as this is not a high priority.

Also trended it the cumulative lbs of CO2 that is spewed out based on my consumption.  I reset the counter at midnight every night. I do the same with costs and kWatt-hr consumption.

If I had to Start Over

I would have wired and programmed the solution to handle updates over the xbee.  I settled for plugging the laptop in the device and load changes that way.

Next Project

I would like to stuff the server side software in a fanless PC like an ARTiGO. I must admit this stuff is boring and prefer to venture into more math/physic problems. Migrating the server side software is not really a project and more something I have to do  as one of my desktop PCs is doing the data collection.

The next project is to measure the temperature in different rooms and just use the XBee and a temperature transmitter. I also want to sense the on/off of key appliances as well over XBee. Alas, I don’t have the cycles to work on this as this is a part-time hobby.

So far I slapped together an Arduiono with XBee and transmit the temperature over modbus as illustrated in the diagram below.

Arduino as-built

The power monitoring Arduino has a slave ID of 2 and the temperature Arduino of 3. Using an Arduino to collect a temperature is overkill and is why I want to change it to be low power over a mesh network around the house. I may have a data concentrator over modbus to bridge the mesh with the host and something like the diagram below. Who knows.

Arduino to-be