Shashank Priya and his team of researchers at Virginia Tech in Blacksburg have created a unique device that lets users shake their cell phone whenever they’re desperately in need of some battery juice to make that all important call. Turning movement into usable energy, the emergency cellphone charging mechanism is based on the use of piezoelectric elements that are placed behind the keypad to harvest energy from the force generated by your fingertips.
Apart from harnessing energy from keystrokes, the charger also replenishes the battery when the phone is vigorously shaken. The system uses zinc oxide, a common piezoelectric material that converts vibrations from sound and pressure into energy to power a cellphone. During tests the research team was able to produce an electric current at about 50mV which could be stored for later use.
Though the system doesn’t produce enough energy to serve as a main charging mechanism, the piezoelectrics produce enough power for that all important call in an emergency. For routine use, the same team has developed a micro wind turbine charger that fits into a water-bottle-like container. This charger generates about a watt of power from wind speeds up to 10kph and can juice up your cellphone battery in about 45 minutes.