According to technology.newscientist.com
"Wireless cellphone headsets give the user freedom to wander around when chatting or to talk safely on a mobile phone while driving. But they don't give you complete freedom – their batteries require regular recharging during which time they can't be used.
Now US manufacturer Plantronics, in Santa Cruz, California, has designed a way to use the movement of a person's head to recharge the headset battery.
The energy harvester consists of a small flywheel in a magnetic field that rotates when the head shifts, thus generating current.
The company says the device should allow more or less non-stop talking without using cables. Whether the users will have to nod continuously while chatting, isn't stated."
