Gravity Light

thingiverse

I designed this gravity light using a motor from an old microwave oven. This light will provide enough light to read with for about five to ten minutes depending on the height that the generator is mounted above the floor, the weight used and the individual characteristics of the motor. An estimated 16 percent of the world's population - one billion people - have little or no access to electricity: https://mashable.com/2017/09/15/one-billion-people-don-t-have-access-to-electricity/ This is designed as a school project, the skills/knowledge to be gained include: 3D printing Pulleys Electricity Light Soldering Tying knots (fishing & others) Social Science & 3rd world awareness PERFORMANCE: Performance varies depending on many things, so using the best of five motors that I had tested I measured the performance - using an LX Meter App on my phone, and with the reflector twelve inches above the meter and the generator ten feet above the ground: Weight - LX - Time = = = = = = = 1kg - 32 - 8:10 1.15kg - 45 - 7:45 1.3kg - 62 - 7:00 As you will see in one of the photos, to get the weight of 1.3kg I used a 1 liter water bottle and two magnets from a microwave oven. What I found was that each motor needs a different weight to get to the point where the LX level suddenly increases. The most efficient motor that I found was the Galanz GAL-5-240-TD. NON-PRINTABLE PARTS: 1 x turntable (tray) motor either from an old microwave oven or from the internet (220-240V 4W Synchronous Motor) I have not tried a 110V motor yet. The photos attached show two different brands of motor that work and a different brand that does not work. 4 x Silicon diodes (e.g. 1N4148) 2 x 1000uF 63V Electrolytic Capacitors or 1 x 2200uF 63V Figure 8 speaker cable or similar Braided fishing line Aluminum foil from your kitchen A suitable container for the weight (e.g. a milk bottle) TOOLS: 3D printer Soldering iron Various hand tools Light meter or an App on a Smart Phone (e.g: “Physics Toolbox Sensor Suite”) NOTES: Do not pull the left-hand side of the curtain chain, as the Tension Post may break. The assembly needs to be mounted to a wall or other vertical surface, not a horizontal surface. The LED can be hung from an appropriate point or print the 3D brackets and make a table lamp. Where the screws are going into the plastic without a nut, they will tap into the PLA plastic to make their own thread, so if the plastic used is very hard it may be best to file a slight point onto the screw tip. KNOTS: Reef Knot - for the water bottle harness Uni Knot - on each end of the braided fishing line Figure 8 - for each end of the cord holding the frame to the wall KITS: My son is keen to make some pocket money, so he is going to provide kits for those that are interested. All you will need is a 3D printer, PLA filament, some aluminum foil from your kitchen, and a suitable container for the weight. The kit will probably cost about $AUS30 to $AUS40 ($US25 to $US35) per kit including shipping. ASSEMBLY INSTRUCTIONS: I will write these up over the next few weeks if there is enough interest. ENHANCEMENTS: I would be really interested in any enhancements that you make or suggestions that you have. A challenge is to build a gear box to double the revolutions of the generator in order to either double the duration or double the light intensity depending on whether or not you double the weight. A very subtle refinement could be to replace the silicon diodes (junction voltage of say 0.6v) with Schottky diodes (junction voltage of say 0.3v) or fast switching diodes, but I don't expect it to make any visible difference.