Chargers for the 21st century

Our cellphones have become an integral part of our daily existence. When our batteries die, it's like we've lost a limb.

To keep up with the modern connected lifestyle, researchers and developers have come up with some novel ways to keep our precious devices going when a normal charger just won't cut it. From fire to soundwaves, here's a look at some ways to keep cellphones going.

Dr Sang-Woo Kim, of the Sungkyunkwan University in Seoul, has reportedly developed a potentially revolutionary technology that uses sound waves to charge a cellphone.

Sang-Woo and his team have designed a device made out of miniscule zinc oxide strands squeezed between electrodes. When sound waves (from speech, music or general noise) hit a special pad connected to the device, the zinc wires vibrate, generating electrical current.

The device is still in its prototype phase, and its capabilities fall just short of actually being able to charge a phone, but it seems hopeful that the technology may soon allow phones to be charged while the user talks.

A Japanese company has developed a new way to charge a phone - just add fire.

The Hatsuden-Nabe thermo-electric cookpot converts the heat of boiling water into electric energy to charge a phone (or other device) through a USB port. The pot has thermo electric strips that generate electricity based on temperature differences between water and the pot. The idea for the cookpot arose as a result of the recent disaster that hit Japan.

The cookpot takes three to five hours to charge an iPhone, and can cook something or make a cup of tea with the hot water while the user waits.

Orange has developed a new concept charger that comes in the form of the Orange Sound Charge T-shirt, intended to be worn at music concerts. The device is set to be tested at this year's Glastonbury Festival.

A piezoelectric film panel on the front of the T-shirt absorbs sound waves and converts them into an electrical charge via interlaced quartz crystals that is then stored in a battery.

If sound levels are kept at a constant around 80dB, the shirt is said to be able to produce enough energy to charge a smartphone, or two lower-end devices.

The MiniPAK portable electronic device charger, designed by Horizon Fuel Cell Technologies, makes use of hydrogen fuel cells.

The charger consists of a "solid-state" hydrogen storage unit and a passive air-breathing fuel cell, which “breathes” oxygen from the air. The oxygen then reacts with the hydrogen to create electricity.

The Horizon MiniPAK is compatible with a variety of phones and can also be used for other electronic appliances. Horizon says its charger brings 10 times the power of traditional batteries. The MiniPAK is not expected to be widely available until next year.

ThinkGeek has designed a charger that is not only portable, but can be worn on the wrist - the Universal Gadget Wrist Charger.

The new-age watch-like device allows for charging on the move and supports gadgets with a mini USB port. Users can walk around talking on their phones, without having to take their phones off charge.

The charger itself, which uses a rechargeable lithium-ion battery, has to be recharged when it runs flat.

The Sidewinder portable cellphone charger works completely independent of electricity, but requires a bit of physical labour.

Winding the charger up at a speed of roughly two revolutions per second generates enough power to recharge a cellphone battery. According to the manufacturer, two minutes of winding up the charge will provide up to six minutes of talk time and up to 30 minutes of standby time.

To talk while charging may, however, prove somewhat difficult (for obvious reasons).