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.
Four rectifier diodes.
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.