November 6, 2013 — Combine a weight, a rope, an LED, inspiration and some savvy crowdfunding, and what do you get? GravityLight. Developed by British inventors Martin Riddiford and Jim Reeves in response to a challenge by SolarAid to find inexpensive substitutes for health- and environment-harming kerosene lamps in areas without electricity, this pulley-based lamp produces up to 30 minutes of light each time the bag at the other end of the rope is hoisted. Buoyed by resources garnered in a beyond-their-wildest-dreams successful Indiegogo fundraising campaign, Riddiford, Reeves and team started rolling GravityLights off the production lines last month. The first lights will be provided free of charge to beta testers in Africa and Asia — with a goal of eventually being able to sell them for $5 each, bringing new light to some of the estimated 1.5 billion-plus people around the world who lack reliable access to electricity.