When you can't find a power socket, use a wind-up charger
A wind-up charger for mobile phones could make a big impact in developing countries where power supplies are often erratic.
This is according to Freeplay Energy chairman, Rory Stear, who is showcasing the company's new phone charger at the Consumer Electronics Show in Las Vegas, US.
"We've just completed a very detailed market research study in three different markets in Africa," he told BBC News Online.
"We put chargers into people's hands to see exactly how they would work and the result was phenomenal."
The 'mobile' mobile
The charger, called FreeCharge, allows phone users to extend their talk time by up to five minutes for every 45 seconds to one minute of cranking.
The more you wind, the more you charge the phone. An internal battery can also store extra energy, providing the convenience of an extra battery which can be recharged anywhere, anytime.
"This device truly makes the mobile 'mobile' for the very first time," said Mr Stear.
The charger will be available for Motorola phones in March and for most other major mobiles within the year.
It will cost $65, which is out of the reach of many in developing countries. But next year, Freeplay intends to bring out a specific charger for the developing world at half that price.
Cutting the cost
"Sub-Saharan Africa probably only has 20 to 30% electrification - yet the growth of mobile phones has been outstanding," explained Mr Stear.
"Nigeria, for instance, is just opening up and the growth there is incredible."
"Some of the service providers in these countries are very interested because it is in their interest to supply access to energy and keep people connected as much as possible."
Mr Stear explained there were even ways of making the charger available at no additional cost to the phone user.
"If the mobile phone providers get involved with the product, I believe there is an opportunity for them to sell a charger along with a phone and a pay-as-you-go contract and obviously subsidise that to consumers," he said.
Freeplay, set up in 1994, is best known for its wind-up radios. It is the world's leading developer of self-sufficient energy technology.