convertting flashlights

[newguy]

has anyone made their own flashlight that doesnt need batteries i mean the ones where you shake it and it makes its own electricity.

i saw one in the store and it looked simple to me all it had was one rare earth mag and a coil that it passed through then a little tiny battery and a led has any one made one of these what do you think i think ill try to make one later

[Epower]

Hi newguy, What you see inside the shake flashlight is not a battery. Its is a "super capacitor" ( button cell ) made by NEC and they come in all sizes. Other companies manufacture them as well. I hope this helps... Epower

[kurt]

there are 3 magnets 1 coil 1 capacitor 1 rectifier diode 1 switch 1 resister and 1 led in those shakelight flashlights actually. (there a bit more complex than they look) the cap is a 5.5v 1/2 farad computer power supply cap and the mags are positioned like this.

n(smallmag)s   s(bigmag)n     n(smallmag)s

that why as you shake it the small mags repel the big mag as it gets close to the ends of the tube keeping it from crashing into the ends of the light and breaking stuff.

the big trick to making one would be getting the right number of turns of the proper size wire to charge the cap without overvoltageing it. capacitors don't like overvoltage much.

[jacquesm]

I've also seen them with springs instead of the two outside magnets, but these springs are pretty tricky because they have to be non magnetic!

[ghurd]

Mine just has rubber bumpers.

G-

[juiced]

all that extra wiring explains why they arent water proof. I use a pump-light that loves taking a bath with me!

[richhagen]

In my basement workshop, I just have a stepper motor with connected through LED's for an emergency light.  Not fancy, and not water proof, but it actually works pretty good, I used to have it charge a memory capacitor, but I stripped the caps for other use.  Its still great for getting to the breaker box.  Rich hagen

[troy]

The name brand shake lights are indeed waterproof. Here's a quote from the website:

"Operational at an ocean depth of 180 ft. (55m) Performance unaffected after being driven over by 4 x 4 truck on concrete surface."

That's a lot more waterproof that you are, especially after being run over by a truck!

And here's the link:

http://shakelight.notanumberinc.com/flashlight/techspecs.shtml

Now, some of the cheap knock-offs may not be waterproof, but that's a whole other deal.

I have two on order by the way, one for the old man's birthday, and one for me too!

Good luck and have fun!

troy

[juiced]

Thank you!

  I did not know that.