How to Build a Magnetic Flashlight
Flashlights are handy items, but a dead battery renders a flashlight useless, so fresh batteries must always be available. You can, however, make a flashlight that uses magnetic power. You'll need a few household and hardware items, plus an LED from a hobby store. The magnet-powered flashlight will never need batteries and will always be ready to light your way.
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Things You'll Need
- Newspaper
- Ruler
- Pencil
- Spool of 16-gauge electric wire
- Wire cutters
- Wire strippers
- 16 ounce plastic water bottle
- Cellophane tape
- Electrical tape
- Scissors
- 4 small, rare earth neodymium magnets
- Utility knife
- White LED
- Soldering iron
- Solder
- Silicon paste
Instructions
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1
Put the newspaper down on a work surface. Place an empty water bottle and the water bottle cap on the newspaper. Let the empty water bottle and cap dry, if necessary.
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2
Use the ruler to measure five inches up from the bottom of the water bottle. Mark a line using the pencil. Measure six inches up from the line using the ruler. Make another line on the bottle with the pencil.
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3
Wrap electrical tape around the line near the bottom of the water bottle. Continue wrapping the tape around the bottle until the tape circle is 1/2-inch thick. Cut the tape off from the roll with the scissors. Repeat this procedure at the other line.
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4
Wrap the electric wire around the water bottle inside of the two lines of electrical tape. Leave 10 inches of electric wire trailing free at the bottom line. Stop wrapping the wire once it's circled the water bottle 200 times. Leave six inches of electric wire trailing free at the top line. Cut off the wire from the spool using the wire cutters.
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5
Put some cellophane tape around the electrical wire that's wrapped around the bottle, to help hold the wire in place.
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6
Use the utility knife to cut a small hole in the center of the bottle cap, and to make a small notch in the side of the bottle cap. The hole must be large enough for your LED to fit through.
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7
Insert the white LED into the hole in the bottle cap from the inside, so the white LED peeks out from the hole. Apply silicone paste around the hole to cement the LED into place. Let the thermal paste set.
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8
Use the wire strippers to strip 1/2 inch of insulation off of each of the two wires that are trailing off of the water bottle. Solder one of the wires to one of the two conductive pins of the white LED. Solder the other wire to the other conductive pin of the LED.
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9
Drop the magnets into the water bottle. Arrange the wires attached to the white LED so they go through the notch on the side of the bottle cap. Screw the bottle cap onto the water bottle.
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10
Shake the water bottle to cause the magnets to move across the coiled electric wire and generate electricity to power the LED. Look at the light coming out of the LED that is being generated by your magnet-powered flashlight.
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Tips & Warnings
You can use any kind of plastic container for the body of the "flashlight."
Using the wrong kind of magnets can lead to insufficient power for lighting the LED.
