The Gravity Light Foundation
Today, over 1.5 billion people have no reliable access to mains
electricity. These people rely predominantly on extremely hazardous kerosene.
Martin Riddiford and Jim Reeves from London Brunel University, with financial support via a crowd funding campaign, have been able to develop GravityLight and in October 2013 gifted
the first 1200 trial units to Africa and India.
GravityLight is powered by a weighted bag that, when lifted by
hand, drops slowly to the ground providing up to 25 minutes of
Being an ancient system, it is considered an Open Source design.