This is a gravity lamp that does not require batteries or any power source. It uses the weight of x4 250ml cans filled with sand to produce the energy required to light the 8 LEDs.

The power is generated by a stepper motor (42BYGH208-12) and it will run for about 3 and a half minutes (form a height of 2m) after which the weight will have to be lifted and hung on the next hook. As the weight goes down, the hook on the ground will rise so the weight can be moved again once it touches the ground. 

To convert the AC to DC I used 8 diodes (1N4148) wired as per diagram attached. 

I have also used a 4700µF 35V 85°C capacitor that helped reducing the flickering of the LEDs and gives a few more seconds of light once the weight has touched the ground so you can see while changing the weight from one hook to the other. 

All the plastic components are printable without support. 

List of parts: 

- x1 Stepper motor (42BYGH208-12)

- x8 Diodes (1N4148)

- x1 Capacitor (4700µF 35V 85°C)

- x8 LEDs 3-6v (White 5mm diameter)

- x1 Axle Rod (3mm diameter, 76mm long)

- x2 Bearings (10mm outer diameter, 3mm inner diameter)

- 6m Fishing line (0.32mm)

- x2 M3 Bolts (30mm)

- 2 M3 Bolts (15mm)

- x4 M3 Nuts

- some wires

- Hot Glue gun

- x4 Cans filled with sand (250ml)

Video:

https://youtu.be/dHls5iG4jC0