Flashlight With No Batteries





Introduction: Flashlight With No Batteries

Flashlight Contest

Runner Up in the
Flashlight Contest

This is a simple method to make a flashlight that will last forever.
It uses a small stepper motor to generate energy and many capacitors for keep it stored for several seconds.

Ps: I'm from Argentina so let me know any grammar mistake.

Step 1: Materials

Most materials are recycled from the trash.

You will need:
  • Two LEDs, with their silver led holdres.
  • An unipolar stepper motor with its reduction gear.
  • One or two broken PC motherboards, to remove the capacitors.
  • Two 220 ohm resistors.
  • A sheet of cardboard.
  • A small piece of plastic.
  • Plastic spacers.
  • Four rectifier diodes.
  • Spray paint.

Step 2: Prepare the Capacitors

The key to the lantern is to put capacitors in parallel to be interpreted as one large-capacity capacitor.
I use 40 capacitors of 1000uf 10v.
If you use more capacitors the torch will stay lit longer.

Solder four rows of 10 capacitors each one.
Then solder the rows together.

Step 3: Make the Carboard Case

Draw the box on the cardboard.
Trim the excess parts and fold by the lines.
Paste a strengthening in the areas where the motor will be attached.
Use double-sided tape to close the box.
If your cardboardis very hard use scotch tape to keep it closed.

Use the pdf file attached as a guide.

Step 4: Paint the Cardboard

Paint the cardboard to make it look better and be more resistant to moisture.

Step 5: Prepare the Motor Connector

Solder the four diodes to the contacts of the individual coils of the motor in the male connector and a small piece of wire to pin cable which connects the common of the four coils.

Step 6: Finishing the Inside

Solder the output of the four diodes to the positive of the capacitors and the wire to the negative.
Solder two pieces of wire on the opposite side of the capacitors.

Then insert it into the box.

Step 7: Leds

Cut the plastic about the size of the top.
Drill two holes for the led holders and paste.
Inset leds, solder two resistors in the positive terminals of the LEDs. Solder the negative together.
Then solder the wires coming out of the box and paste the plastic to the cardboard.

Step 8: Attach the Motor

Use a zip tie to attach the motor to the cardboard box, remember to connet it to the capacitors.

Step 9: The Handle

Use a small piece of plastic and hte spacers to make a handle and paste it strongly to the motor gear.



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Tenia pensado en hacer algo asi yo tmb. Nunca sabes cuando necesitas una para alumbrar a un demonio que es debil a la luz y que te ha destruido toda la iluminacion de la casa :P..

Creo que tengo un motor chiquito de continua(no paso a paso), capaz que pueda servir igual. Y concuerdo con que un envase de plastico ignifugo seria mas conveniente. Por lo demas, muy buen trabajo!.

Look up laser hacker.com he had some joule looper circuit that relly conserve the power to run an led from a super capacitor.

can we use a charging circuit to charge some rechargable AAA batteries and use them in place of capacitors . They can turn the lights on for a long time.


The name of of the project is "Flashlight with no batteries" If you want a flashlight with batteries, there are millions out there in the store.

Rechargeable AAA batteries, depending on the type, will need a complex charger to prevent overcharging and it has to be at a certain voltage.

Those circuits are very complex, its not easy.

what type of capacitors did you used

Great looking diy no battery light, I agree with crumpton that pvc or something would look better and be easier to carry.

Great project, but for a project this nice I think you might do better to put the body in a plastic box like a tupperware, or maybe a piece of PVC pipe rather than cardboard.