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It is a noisy, yet a novel idea. Extremely useful to talk to your near and dear ones while moving around the house doing chores. The arduino controlled two 5V relays with 12 V 40A car relays prove as the base hardware. The control system however, consists of a simple html page with ajax calls to php scripts that sends serial commands to Arduino using this.
The complete know-how along with code can be found here.
[Via: Hackaday]
[original story: Arduino Blog]