66% or better

Tweet-a-Watt kits

tweetawatt

[adafruit] wrote in to let us know that the Tweet-a-Watt is now available in kit form. While the plans have been available for a while, a kit is a welcomed addition. The kit doesn’t include the Kill-a-Watt monitor, but rather the XBee adapters and parts necessary to make it talk to your Arduino or computer. The kit is $90, while the Kill-a-Watt can be found for roughly $20.

Tweet-a-Watt wins Greener Gadgets design competition

tweetawatt

The team behind the the Tweet-a-Watt/Wattcher just won first prize at the Greener Gadgets design competition. The device is a hacked Kill A Watt that transmits power consumption using an XBee. After checking out DVICE’s preview of the competitors yesterday, we’re happy to see a prototype win instead of just a concept sketch.

Ferric chloride etching chemistry

etch

[ladyada] has republished an interesting snippet from the synthDIY mailing list. [David Dixon] discusses the actual chemistry behind ferric chloride based home circuit board etching. He concludes that ferric chloride is essentially a ‘one-shot’ oxidant. It can’t be regenerated and can be difficult to dispose of properly. The use of acidified copper chloride is a much better path and becomes more effective with each use, as long as you keep it aerated and top up the acidity from time to time. This etchant solution is actually the result of initially using hydrogen peroxide as an oxidant along with muriatic acid. You can see us using this solution in our etching how-to and while creating the board for our RGB lock. For more information on using hydrogen peroxide, check out [Adam Seychell]‘s guide and this Instructable.

Aside: [ladyada] has added the receiver code to the Wattcher project page.