TWEET-A-WATT! A Power Monitor That Twitters Your Energy Use

Tweet-a-watt est un projet qui permet de monitorer les consommations de votre maison directement sur Twitter. Ce projet qui se défini comme un projet “Open source hardware” permet a n’importe qui de modifier leur kit pour l’adapter a n’importe quel produit. La démo d'un compteur qui gazouille sur twitter est ici http://twitter.com/tweetawatt



The Tweet-a-Watt is one such example. Using a modified version of a $20 off-the-shelf wattage meter, the Tweet-a-Watt kit, now available online for $90, tracks daily power usage for an outlet. It then reports that information back to your followers via your Twitter account, including the daily average and your daily goal.

The kit includes the wireless transmitters and receivers needed to report the data, plus cables and various components needed to get it all wired up. It's the product of an open-source hardware project that had the main goal of wirelessly tracking power usage for a household. The Twitter aspect is a fun byproduct of this idea.

For DIY'ers, there are instructions for making your own kit and links to download the software for your project.

It's great for people who want to keep track of their carbon footprint, and even better for those who like to show off their conservation efforts to their fellow smug friends. You know they're out there.

The meter tracks a specific outlet, though you can buy multiple kits for other outlets and have them all report to the same Twitter feed (that seems excessive). I'd love to see a kit like this for household power, maybe something you plug in at the main terminal for your house. Or maybe I could just bypass Twitter and give my apartment its own blog? I'm sure it's got wonderful things to say about me.

http://news.cnet.com/8301-17938_105-10205534-1.html

Compare ZigBee Specification Versions

Une comparaison synthétique des évolutions de Zigbee.

The ZigBee Alliance creates technology standards designed to create a thriving market for a variety of uses.

The ZigBee 1.0 specification was ratified in December 2004, and is referred to as ZigBee 2004. In December 2006, the ZigBee 2006 specification was released, which was followed in October 2007 by the ZigBee 2007/PRO specification. Each new release adds to and improves functionality provided in previous versions of the specification.

The chart below provides a high-level comparison showing the similarities and differences between the 2004, 2006, and 2007/PRO ZigBee specifications.

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Comparison chart

		2004	2006	2007	PRO
Interference avoidance
	Network coordinator selects best available RF channel/Network ID at startup time.
	Support for ongoing interference detection under operational conditions and wholesale adoption of a new operating RF channel and/or Network ID.
Automated/distributed address management
	Device addresses automatically assigned using a hierarchical, distributed scheme.
	Device addresses automatically assigned using a stochastic scheme.
Group addressing
	Devices can be assigned to groups, and whole groups can be addressed with a single frame; thereby reducing network traffic for packets destined for groups.
Centralized data collection
	Low-overhead data collection by ZigBee Coordinator explicitly supported.
	Low-overhead data collection by other devices supported under special circumstances (e.g. with Tree Routing).
	Many-to-one routing allows the whole network to discover the aggregator in one pass.
	Source routing allows the aggregator to respond to all senders in an economical manner.
Security
	128-bit AES encryption with 32-bit Message Integrity Code (MIC) and frame counters to assure message freshness.
	Security applied at the NWK layer by default, with key rotation to prevent hacking of the NWK key.
	Higher-layer security supported.
	Trust Center application, operating on the ZigBee Coordinator, manages trust on behalf of network devices and acts as the central authority on what devices can join the network.
	Trust Center can run on any device in the network.
	"High Security" mode available, which is selectable by Trust Center policy, and requires Application Layer Link keys; peer-entity authentication; and peer-to-peer key establishment using Master Keys.
Network scalability
	Network scales up to the limits of the addressing algorithm. Typically, networks with tens to hundreds of devices are supported.
	An addressing algorithm that relaxes the limits on network size. Networks with hundreds to thousands of devices are supported.
Message size
	< 100 bytes. Exact size depends on services employed, such as security.
	Large messages, up to the buffer capacity of the sending and receiving devices, are supported using Fragmentation and Reassembly.
Standardized commissioning
	Standardized startup procedure and attributes support the use of commissioning tools in a multi-vendor environment.
Robust mesh networking
	Fault tolerant routing algorithms respond to changes in the network and in the RF environment.
	Every device keeps track of its "neighborhood"; thereby further improving reliability and robustness.
Cluster Library support
	The ZigBee Cluster Library, as an adjunct to the stack, standardizes application behavior across profiles and provides an invaluable resource for profile developers.

Backward compatibility

ZigBee 2007/PRO

• Backward compatibility with ZigBee 2006 required.
  
• Backward compatibility with ZigBee 2004 not required.
  

ZigBee 2006

• Backward compatibility with ZigBee 2004 not required.
  

ZigBee 2004

Original ZigBee version.

Source:
http://www.daintree.net/resources/spec-matrix.php
via http://twitter.com/DaintreeNet/status/2198379161