1. Gravity Lamp LIGHTING FOR THE DEVELOPING COUNTRIES

2. GravityLight is powered by gravity without the need of a battery, it's also seen by its creators as a superior alternative to solarpowered lamps. 3. The gearing took the kinetic energy from a weighted bag descending at a rate of a millimeter per second to power a dynamo spinning at 2000rpm. 4. There is two gravity powered lamps: Gravia LampGravity Lamp 5. The gravity powered floor lamp The gravity-powered lamp envisioned by Clay Moulton, a graduate student at Virginia Tech that his lamp won second place at the 2008 Greener Gadgets Design Competition. Let's start by looking at the lamp's inner workings. 6. The lamp is a standing floor lamp, 147 centimeters tall and cylinder-shaped. Inside the cylinder, there are several basic parts involved in creating light: brass weights, a ball screw, a drive gear, a rotor, generator and a bunch of LEDs. 7. All of this happens over the course of four hours, and the LEDs, which light up a few seconds after the weights start to drop, remain on for that full period. They emit between 600 and 800 lumens, which is comparable to a typical 40watt bulb. When the weights make it to the bottom of the lamp, the LEDs go out, and the person who started the chain of events has to input more power by moving the weights back up to the top of the screw. 8. Attaching five 4.5 kilogram weights Downward motion converts into rotational motion The spinning gear spins a generator The electricity powers 10 LED bulbs for 4 hours 9. What is a Ball-screw? A ball screw is a mechanical linear actuator that translates rotational motion to linear motion with little friction. 10. Linear actuator A linear actuator is an actuator that creates motion in a straight line, as contrasted with circular motion of a conventional electric motor. Linear actuators are used in machine tools and industrial machinery, in computer peripherals such as disk drives and printers, in valves and dampers, and in many other places where linear motion is required 11. Mechanical linear actuators typically operate by conversion of rotary motion into linear motion. Roller screw actuatorRigid chain actuator