Kit of the Month: Twitter Your Home's Power Consumption

Build an energy monitor that broadcasts your energy usage to the world

By Mike Haney Posted 08.04.2009 at 9:35 am 7 Comments

Juicy Details Twitter users can keep tabs on how much energy your Xbox and other electronics are consuming. Luis Bruno

Nothing motivates like peer pressure, whether it’s friends goading you into one shot too many or friends tracking your power consumption on Twitter. That’s the thinking that led Limor Fried and PopSci contributing editor Phil Torrone, circuit wizards who run the electronics-kit seller adafruit.com, to cross a small power monitor with an XBee wireless home-automation module and a few lines of code.

The result of their experiment is the Tweet-A-Watt. The setup starts with the popular and inexpensive Kill A Watt power meter, which plugs in between any appliance and an outlet and displays how many kilowatts are being used. The XBee module sends that data to a computer, which broadcasts to a Twitter feed so your legions of followers can, in theory, watch your watts go down over time.

Last spring, the project won the pair the Consumer Electronics Association’s Greener Gadget contest and coverage on CNN. Now it’s available as a kit for sale at their Web site. It’s open-source, so you can see all the code, parts and methods they used to build it, and modify it as you like to expand its functionality. The kit involves some soldering and programming but comes with crystal-clear step-by-step directions. After enough updates, your followers are bound to start telling you to shut off your air conditioner more often — if you haven’t already decided to do it on your own.

Tweet-a-Watt Dissected: Luis Bruno

Build Your Own Tweet-a-Watt

Time: 2 Hours
Cost: $120

1. Buy the Tweet-A-Watt starter pack ($90) at adafruit.com, and pick up a Kill A Watt meter ($30) at an online retailer or any big-box store.

2. Solder together the XBee receiver, which plugs into your computer to pull in the data broadcast from the Kill A Watt.

3. Plug the XBee modules into your computer’s USB port, and adjust the settings.

4. Assemble the XBee transmitter.

5. Open the Kill A Watt box, and drill a hole in the top for the LED that will tell you the unit is broadcasting. Solder the transmitter to the Kill A Watt board.

6. Follow the instructions to run the code that will configure the Tweet-A-Watt to send the data it collects to your Twitter account.

7. Plug the Kill A Watt meter into a wall outlet, and plug an appliance into the meter. You can also plug a multi-outlet power strip into the meter and monitor the power consumption of an entire room of your house.

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7 Comments

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ckmapawatt

07/22/09 at 8:28 pm

Chris K
Founder of http://blog.mapawatt.com

The tweet-a-watt is a nice concept, but in reality it does little to give you an idea of how much total energy you are using in your home. Since the tweet-a-watt is based on the kill-a-watt, it can only monitor a single circuit, and not your whole home's energy consumption. To measure your whole home, you need a device like the TED 5000.

Bottom Line: Good for posting your entertainment system's energy consumption, bad for the big picture.

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07/23/09 at 11:39 am

hi chris, please read the site and documentation - the tweet-a-watt is cheaper than the product you are promoting, the TED 5000 is at least $200 and it's pre-made, not a kit (the title of the article is *kit if the month*).

the TED looks very cool, but many people do not need or want a solution like the TED 5000 (it is also not released according to the site, you can't actually order it).

many people live in apartments (we do) and if you don't have that many things plugged in to outlets *and* you might not have access to a breaker panel, the tweet-a-watt kit might be for you. some folks work in an office and only want to monitor their office, etc etc...

"out of the box" tweet-a-watt sends data to the google app engine as well as twitter.

the tweet-a-watt can work with a breaker panel, the project is open source, many people have made mods that do more. that's the nature of a kit, it also teaches folks how to measure power, do electronics - that's what the big picture is about :)

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ckmapawatt

07/23/09 at 1:52 pm

Chris K
Founder of http://blog.mapawatt.com

I guess I mis-typed when I wrote, "bad for big picture" because this is bad label and wrong for me to say. As you point out, the tweet-a-watt has more ability than to just measure a single circuit, so there is a lot of potential and it is a great tool to help educate and inspire great ideas.

I just wanted to point out that people need to be aware about the big picture (their whole home's energy consumption) when it comes to energy consumption, and the tweet-a-watt is a component that makes up that big picture.

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DerivePi

08/04/09 at 2:31 pm

All we need now is to find a way to make this an online game with prizes. I could just imagine a 9 year old telling the parents that they have to cut down on energy consumption so that they can win against Jimmy down the street. Or, "look honey, our energy consumption is 1 millionth of Al Gore's."

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ryan-t

08/04/09 at 4:17 pm

This is funny. What about Twitter's servers energy consumption handling all the Twitter messages from this kit?

Member of http://hintcafe.com

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ford2go

08/05/09 at 12:33 am

This is kind of fun stuff, but a little silly. Maybe some folks will save a few watt hours, but generally this is a severely limited system.

I looked up Kill a Watt -- they are limited to reading 15 amps in 110 V circuits. So, any serious energy users are out of the question. (e.g. whole house a/c's run on 20 amp 220 v circuits).

This same limit makes the device unsuitable for monitoring overall household usage -- you might be able to hook one up to your circuit breaker panel, but you'll have to limit yourself to a single 15 amp circuit. Breaker panels often range from 150 to 250 amps total, and they have a number of 20 amp circuits.

How about stepping outside and checking your meter once a day or so? If you're so inclined, you can tweet the number.

Also, your friendly power company does supply your monthly energy usage with your bill.

The kit is cute, but I have to give it a pass as being very useful.

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ReubenC

08/13/09 at 1:16 am

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