You can tell some people about being considerate to the environment until you're blue in the face, but they'll still flagrantly waste power. At that point, maybe it's time for the light switch to fight back: Peter Russo and Brendan Wypich of Stanford University have developed the SmartSwitch, a light control that gives tactile feedback as to how much energy is already being used, whenever you try to flick it.
Video demo after the cut
"Equipped with a network connection and a brake pad, the switch provides its user with tactile feedback about the amount of energy being used either within their household or by the electrical grid as a whole.
SmartSwitch doesn't restrict the user from turning on a light, but rather it passively encourages behavior change. SmartSwitches can be programmed to respond to either personal or communal electrical usage. In a home wired with SmartSwitches, lights can become harder to turn on during hours of peak demand. The switches can also be customized to reflect household-specific energy conservation goals."
If the total energy consumption in the house (or area) is low, then the SmartSwitch is as easy to flick on as a normal light switch. However if the consumption is greater, than the SmartSwitch is physically harder to use, thanks to a brake pad inside the mechanism. The idea is that people use this tactile feedback to decide whether or not they really want to contribute to the total energy demand of their house or greater environment.
The SmartSwitch is an entry in the Greener Gadgets Design Competition, and as well as being a decent concept it's also practical. The mechanics of the tactile switch will fit into a standard electrical box, and there's no special wiring necessary as it uses the electricity lines themselves to communicate data.