Rob Spiegel,
GravityLight uses a new simple approach to storing energy and creating illumination for the 1.5 billion people who have no reliable connection to electricity and who have traditionaly burned kerosene for light at night. At an expected cost of less than $5 GravityLight is a realistic alternative to kerosene which is expensive and has a large impact on peoples health and the environment. Simply lifting a weight allows the GravityLight to generate light for 30 minutes as it descends downward.
