A lamp that is powered by gravity.

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 Lamp
Gravity 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 actuator
Rigid chain actuator