Arduino PowerMeter, connect and display

48h after the first post about the Arduino PowerMeter, here is a status about the project.

The fund raising is going really well, already 50% of the needed funds are here, the first Arduino is virtually connected to the electricity counter!

Teleinformation

It appears that EDF, the historical french electricity distributor, has alreayd thought about people wanting to retrieve electronically information from their home control panel.

At the bottom right of this picture, you can see 2 holes named “Sortie de téléinformation client (unidirectionnelle)” which is a serial port, with certain specifications, that sends a binary stream of the informations available on the LCD panel.

Then I found this wonderful wiki in vesta.homelinux.net, with all the code necessary to decrypt this stream, and some even more hard-core experiment connecting a linksys router and sending information on a remote mysql database. Until then, I’m not the only one geekying my time :)

Now, it’ll save me the photo-diode surely-complicated thing on my first design, and I’ll just need to figure out how to demodulate the signal send by this port:

“Les infos sont transmises cycliquement sur la ligne, modulées en ASK à 50kHz, ce qui correspond en gros à : soit aucune tension présente, soit un signal à 50kHz de 10V CC environ. Le 0V équivaut à un 1 logique, le 50kHz à un 0 logique.”

Thanks to Luj06 on the french Arduino forum to have told me about this serial port.

Displaying numbers

What’s the most versatile technology today to follow a counter during days and weeks?

My answer tonight would be: “web analytics”

All the code is there, with Piwik as the flagship of the open-source tracking system.

If we compare the counter we’ve got on our electricity panel, it’s like a counter on a webpage during the nineties: a suite of number without more meta information.
In today’s world, this counters has been replaced by web analytics portal: it’s far more simple to install it that the previous counter, it gives you a lot of information on a simple glance, and everybody can read it.

So let’s experiment this way: visit would be replaced by watt/hour (the small led signal on the counter), and navigator field will serve to record the rate of the visit (full-rate, half-rate).

Surely Piwik will look a bit empty with only the small part of informations, but it’ll be a nice framework to start working on, hopefully with easily understable code.

On a side note, I’ve also got access to Pachube.com beta, so I’ll need to send the information there, and retrieving information from it could add another layer in the “electricity analytics” portal: other people are running energy consumption nodes on Pachube, getting their geo-localisation and their energy feeds will bring a nice mix of information that could be shown.