One of the biggest losses of electricity is when you have your cellphone charger plugged into the wall but your phone is not plugged into your charger. If we could save every little bit of electricity from all the cellphone chargers in the world, this could be significant enough to power a country. Of course, there are gadgets like CheckTap, which will allow you full control over all your devices that are not powered on.
This DIY is a simple circuit that will automatically unhook your AC adaptor when you unhook your cellphone from the adaptor, great idea.
Unused power adapters should be unplugged for a greener planet, everybody knows it. Nonetheless I keep seeing them plugged all the time, everywhere.
From an interaction designer’s perspective, the reason is clear: wall warts aren’t designed to be unplugged – period.
As a design excercise, I have built a phone charging station that makes unplugging very easy and instinctive (with affordance playing a big role). So easy you don’t even notice it unplugs automagically. The design is made from cheap and available materials, and was a great fun to build on a rainy day.