The technology behind the wind-up radio could soon be helping to light up some of the poorest homes in Africa.
The Freeplay Foundation has given out more than 150,000 radios
The Freeplay Foundation is developing prototypes of a charging station for house lights it hopes will improve the quality of life for many Africans.
The Foundation said the lights would replace the expensive, polluting and unhealthy alternatives many Africans currently use to light their homes.
Field testing of the prototypes will start in Kenya in the next few months.
Light and life
Kristine Pearson, director of the Freeplay Foundation, said few Africans in the continents most vulnerable areas had access to electricity to light homes.
"Their life stops or is very narrowed when the sun goes down," she said. "Two extra hours of light would make a big difference to their life."
The World Bank estimates that more than 500 million people in sub-Saharan Africa do not have access to electricity supplies that could be used to light their homes.
Instead, said Ms Pearson, many used kerosene lamps, battery-powered lights or wood fires as sources of illumination after sundown.
Buying kerosene or batteries can consume up to 15% of a household's budget, said Ms Pearson. In addition wood was hard to gather and unhealthy to burn.
As part of its LifeLight Project the Freeplay Foundation has drawn up designs for a charging base unit that would be able to power up several detachable lights that can be used around a home.
"They could use them for study or for safety - to help them if they go somewhere at night," said Ms Pearson.
The Foundation aims to train women to sell and maintain the lights
Working prototypes are now being made that will be tested with families in Kenya to refine the design.
Freeplay technology has already been used to create wind-up torches and small lights said Ms Pearson but the LifeLight Project aims to make bigger, brighter bulbs for homes.
She said the Foundation was adopting a similar approach to that used for the wind-up Lifeline radio to get the lights to families.
Instead of just giving the lights out and then leaving, the Foundation aims to recruit women who will sell the lights and be trained to repair and maintain them for customers.
Ms Pearson said the take up of the lights was likely to be rapid because it would piggyback on the network created by the Foundation to maintain Lifeline radios.
Since it was established in 1998 the Foundation has given out more than 150,000 Lifeline radios.
Ms Pearson said the Foundation had applied for a grant to fund the design and testing work from the World Bank as part of that organisation's Lighting Africa initiative.