Say you want to know how much electricity an air purifier is consuming?
You can hook it up to the nifty Kill-A-Watt power meter (aka KaW). The KaW will keep track of and display the killowatt-hours, or kWh, used by the plugged in device.
However, the total will be reset anytime the KaW is unplugged and loses power. Limor Fried (aka ladyada) recognized this shortcoming and created the clever Tweet-A-Watt project which mods the KaW by soldering a XBee wireless data module to the KaW’s op-amp chip.
The XBee’s built-in ADC reads the current and voltage signals inside the KaW and transmits it to a receiver XBee module connected to a computer. This diagram by ladyada gives a good sense of the architecture:
The Tweet-A-Watt (TaW) is an awesome project, but I felt the computer seemed cumbersome and power hungry. Thankfully, we live in an era of powerful, tiny & cheap single board computers (SBCs) like the Raspberry Pi . I decided to use the Pi in place of a traditional computer along the Adafruit LCD Pi Plate and the Adafruit Pi Box enclosure. The receiver XBee module connects to the Pi via a FTDI USB-to-serial cable.
Ladyada used Google AppEngine for graphing the TaW data, but I decided to take advantage of the newer Cosm sensor data graphing service (formerly named Pachube). Below is a screenshot of my RaspiWatt Cosm feed showing Watts, kWh, and USD$ (based on the cost of a kWh for my power company)…
I assembled my Moteino circuit inside the KillAWatt. Everything fits very nicely and the LED blinks every ~2 seconds, and data finds its way to my RaspberryPi where EmonCMS records and graphs it nicely. At the last minute I found a leftover TMP36 analog temperature sensor that I had around, and thought – why not add it to the Moteino and report temperature along with power readings?
I feared the TMP36 sensor alone would draw too much power (even an extra constant 2mA is too much for my KAW!). But it turns out it’s a very low power sensor (just 0.05mA). Since Adafruit has a very nice demo and code for TMP36, I won’t replicate the details here, you can check them out at Adafruit’s learning system.
Now I’m getting temperature, voltage and current waveform readings from my KAW.
There seems to be a lot of concern about how much money other people are spending on electricity for their Christmas lights. I’m happy to report, it doesn’t cost much.
The price of electricity varies from place to place, and from time to time, but a typical price is 12¢ per kilowatt hour. That means that if you burn 1,000 watts for the span of one hour, you’ll pay 12¢.
Modi’s team performed a statistical analysis to estimate New York City-specific building energy use. Their statistical model utilizes zipcode-level energy consumption data to estimate the average annual energy use for every tax lot—at practically building level—through all five boroughs of the city.
This energy use was further broken down into what the building uses for space heating, space cooling, water heating, and base electric applications such as lighting, and, with this information, the Columbia Engineering team created an interactive web map that shows what type of energy is being used, for which purpose, and in what quantity. “This map will enable NYC building owners to see whether their own building consumes more or less than what an average building with similar function and size would,” said Professor Modi. “This is the first time anyone has provided an estimate like this for New York City and the first time anyone has offered information to the public in the form of an interactive map.”
What’s next? We’d like to see someone combine this with peak use data and make certain devices smarter. For example, during peak times in the summer some appliances / devices would be “aware” what’s a good non-peak time to run. The IoT should know when it’s a good time to turn on, and off.
We’re working on our product line up for 2012 and it’s going to be filled with great stuff all of you are going to do amazing things with. One of the things we’re thinking about is how many of the products/projects like the Arduino are getting more networked, and therefore the sensors attached are getting more networked.
One of the earliest projects we did to show this was through a real shipping product was the Tweet-a-watt.
Very soon, with makers/hackers leading the way, devices will favorite, tag, like, follow, friend and un-friend. People like to do this, but smart connected devices will like to do this even more. What it will mean for artists, designers and engineers who creatively use these technologies?
Perhaps one day your Tweeting power meter will automatically “friend” the other ones you install in your home, and if you’re publicly sharing the data they’ll follow others in your area. We believe in open-source and open-source hardware, so you’re always able to know what is being shared, stored and how the device works. We think this is important.
We hope to have some fun examples soon, we’ll be showing some cool stuff on some upcoming ASK AN ENGINEER shows about all this, stay tuned.
A truly innovative Internet of Things will be based on a culture of sharing and collaboration. This award recognizes the year’s best Open Source contributions.
Hello, I’ve just published a conference paper, “A Rice Cooker wants to be my Friend on Twitter” (in the ETHICOMP 2011 proceedings), which gives a reference to Tweet-a-Watt. I thought you might like to know.
Pervasive computing devices are already using Twitter as a communication channel. In the future you may receive unwanted friend requests from inanimate objects. Even if you refuse them all, receiving frequent friend requests can be annoying, and may lead you to mistakenly refuse some welcome friend requests. There are some Twitter validation services which assist and partially automate the decision of which requests to accept; but these have limitations. Without improved validation services, the rise of pervasive computing devices on Twitter or similar networks may degrade the experience of the human users of these networks.
Tweet-a-Watt is a DIY wireless power monitoring system. The project uses an ‘off the shelf’ power monitor called the Kill-a-Watt and adds wireless reporting. Each plug transmits the power usage at that outlet to a central computer receiver. The receiver can then log, graph and report the data. This pack contains nearly everything* necessary to build a single outlet monitor and receiver. To monitor additional outlets, you will need an add-on transmitter pack. One outlet can monitor up to 1500 Watts.
The starter pack contains:
2 XBee modules (one for receiver, one for transmitter)
2 XBee adapter kits (ditto)
1 USB FTDI cable (for updating, configuring and receiving data from XBee)
1 bag of parts including 10,000uF capacitor, 220uF capacitor, 2 1% 10K resistors, 2 1% 4.7K resistors, 5mm green LED, 6″ rainbow ribbon cable, and 2 pieces of 1/8″ and 1/16″ heatshrink
The technicians at iFixit got their hands on an Elster Rex2 Watt-hour meter with features that an old-fashioned motor-driven meter lacks: nonvolatile memory with 1 million write cycles, advanced security with full 128-bit AES (Advanced Encryption Standard) encryption, the ability to make remote upgrades, and support for 900-MHz and 2.4-GHz ZigBee communication. The meter can also track overall power usage by time, which raises privacy concerns for some utility customers. On the other hand, some customers welcome the ability to parse their power usage to better manage it and, they hope, save money.
Bruce Hoult is a software engineer in Wellington, New Zealand. Mr. Hoult signed up for Powershop last April 2009 – mainly to save money, but as soon as he discovered that Powershop offered an open API (Application Programming Interface) he started tinkering with it. Since nighttime power is 25% cheaper than daytime power he set out to shift some of his power usage from the day to evening. He works from his home office and he did what a good enterprising tinkerer does: he ran experiments with his own power usage putting together available technologies in new ways.
“I built a computerized device based on Arduino [a website that offers an open source hardware and software platform for rapid prototyping] that I programmed to turn my heater and dehumidifier on and off at different times of the day”, said Mr. Hoult. “After tracking power, temperature, and cost for a while, I determined that it was optimal to crank up the heater an hour or two before 7am when power cost goes up. It turns out that the walls and the house itself retain a lot of the heat and slowly release it during the day. The result is that I use much less power during the day while maintaining the same temperatures as before.” Over the last twelve months Mr Hoult has saved NZ$500 or nearly 24% compared to the previous year.
I asked him if he was thinking about commercializing this device. “The payback is less than a year so there could be a market for it. However, I’m a technical guy. Marketing is definitely not my thing.”
In the coming months, we’re going to retire two products that didn’t catch on the way we would have hoped, but did serve as influential models: Google Health (retiring January 1, 2012; data available for download through January 1, 2013) and Google PowerMeter (retiring September 16, 2011). Both were based on the idea that with more and better information, people can make smarter choices, whether in regard to managing personal health and wellness, or saving money and conserving energy at home. While they didn’t scale as we had hoped, we believe they did highlight the importance of access to information in areas where it’s traditionally been difficult.
Send a Tweet to @dangerousproto and watch it print live on the USTREAM feed.
This is a soft-launch of our project for the Adafruit/Instructables Make it Tweet Challenge. We’ll have some documentation up on Instructables tomorrow, but we need your help stress testing the system today.
Adafruit + Instructables Make It Tweet Challenge We’re teaming up with Instructables to bring you the Make It Tweet Challenge. Ever wish you had a tweeting coffee pot that would announce via Twitter when a pot was ready? What about a potted plant that twittered when it needed to be watered? This is your chance to make it tweet! How can you win the Adafruit Make It Tweet Challenge? Submit a Photo, Step-by-Step or Video Instructable explaining how you made an object tweet. Create awesome photos, good documentation and clear steps for how your project works. Your creativity and ingenuity may rewarded by winning awesome prizes!
Here at IEEE Spectrum, staffers routinely put Post-It notes on their doors and cubicles to let colleagues know they’re out. But you can’t slap a note on your door if you decide to work at home at the last minute—which, as I learned this winter, happens quite often when you have a very pregnant wife about to go into labor any instant.
That’s why I set out to replace those yellow sheets of self-adhesive stationery with something less, uh, analog—something that would allow me to post the updates electronically. An idea then popped up in my head: Twitter for my door.
It turns out to be a simple DIY project that an experienced hobbyist can complete in a few hours. Or if you’re me and this is your first serious hardware project, it might take you a couple of months and nearly drive you insane.
It worked out in the end. Now, when I’m home—or actually anywhere with my phone—I can send a tweet to a small LCD that hangs by my door, thus keeping my coworkers informed of my whereabouts. The LCD also shows current weather conditions in New York City; I thought my colleagues would appreciate this value-added service.
Adafruit + Instructables Make It Tweet Challenge We’re teaming up with Instructables to bring you the Make It Tweet Challenge. Ever wish you had a tweeting coffee pot that would announce via Twitter when a pot was ready? What about a potted plant that twittered when it needed to be watered? This is your chance to make it tweet! How can you win the Adafruit Make It Tweet Challenge? Submit a Photo, Step-by-Step or Video Instructable explaining how you made an object tweet. Create awesome photos, good documentation and clear steps for how your project works. Your creativity and ingenuity may rewarded by winning awesome prizes!
The Google Power Meter API has been officially deprecated as of May 26, 2011 to reflect that it’s no longer undergoing active development and experimentation, which is the hallmark of APIs in the Code Labs program. However, we have no current plans to remove functionality for existing users.
Google stopped updating their Power meter blog last year (Aug 31, 2010). For the power geeks, you can read our long history with Google’s power metering efforts / competition here. We think it’s an excellent case study for someone out there and a cautionary tale of what happens when Google gets in your market.
At this point, and just our opinion, we’re not really sure PowerMeter is a serious effort at Google and if it will continue, the manager (Ed Lu) recently left, the forums are pretty low volume on the Google site and if you review the Tweet-a-Watt time line it’s not that encouraging for folks wanting to use Google PowerMeter. The folks from Google have posted here before and we’re hoping they re-consider how they’re deploying PowerMeters and what the goal of the project really is…
We got our Tweet-a-watt to work with the Google Power meter API for kicks despite Google ignoring the requests for access from the open source / open hardware community, Google chose only to work with commercial partners and not the thousands of Tweet-a-watt makers out there. It was mostly a war of the press releases as Google didn’t really do much in this space, only making sure other companies in the power metering arena stayed scared of Google, it worked. Google does a lot of cool things, but sometimes they get “grabby” in markets, freak people out, buy a bunch of stuff/people and then just kill off stuff it seems. Happens to lots of companies, Google is working on self-driving cars now.
All that said, we’re excited by the recent developments with Anrdroid + Arduino, mostly because it’s all OSHW and it will continue no matter who or what happens. If you want to build open source power meters, we’ve got you covered, always
Tweet-a-Watt is a DIY wireless power monitoring system. The project uses an ‘off the shelf’ power monitor called the Kill-a-Watt and adds wireless reporting. Each plug transmits the power usage at that outlet to a central computer receiver. The receiver can then log, graph and report the data. This pack contains nearly everything* necessary to build a single outlet monitor and receiver. To monitor additional outlets, you will need an add-on transmitter pack. One outlet can monitor up to 1500 Watts.
The starter pack contains:
2 XBee modules (one for receiver, one for transmitter)
2 XBee adapter kits (ditto)
1 USB FTDI cable (for updating, configuring and receiving data from XBee)
1 bag of parts including 10,000uF capacitor, 220uF capacitor, 2 1% 10K resistors, 2 1% 4.7K resistors, 5mm green LED, 6″ rainbow ribbon cable, and 2 pieces of 1/8″ and 1/16″ heatshrink
The “Netduino+ Tweeting Geiger Counter” is a great example of the type of project you can enter for the Adafruit + Instructables Make It Tweet Challenge…
Adafruit + Instructables Make It Tweet Challenge We’re teaming up with Instructables to bring you the Make It Tweet Challenge. Ever wish you had a tweeting coffee pot that would announce via Twitter when a pot was ready? What about a potted plant that twittered when it needed to be watered? This is your chance to make it tweet! How can you win the Adafruit Make It Tweet Challenge? Submit a Photo, Step-by-Step or Video Instructable explaining how you made an object tweet. Create awesome photos, good documentation and clear steps for how your project works. Your creativity and ingenuity may rewarded by winning awesome prizes!
Tweet-a-Watt is a DIY wireless power monitoring system. The project uses an ‘off the shelf’ power monitor called the Kill-a-Watt and adds wireless reporting. Each plug transmits the power usage at that outlet to a central computer receiver. The receiver can then log, graph and report the data. This pack contains nearly everything* necessary to build a single outlet monitor and receiver. To monitor additional outlets, you will need an add-on transmitter pack. One outlet can monitor up to 1500 Watts.
The starter pack contains:
2 XBee modules (one for receiver, one for transmitter)
2 XBee adapter kits (ditto)
1 USB FTDI cable (for updating, configuring and receiving data from XBee)
1 bag of parts including 10,000uF capacitor, 220uF capacitor, 2 1% 10K resistors, 2 1% 4.7K resistors, 5mm green LED, 6″ rainbow ribbon cable, and 2 pieces of 1/8″ and 1/16″ heatshrink
Printable catalog (PDF)
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