shake light

did enyone now shematic of shake light
i search on google but nothing
sory for my bad english

What is a "shake light"?
What does it do?
What is in it?

Is that "shake" charging torch?

A flashlight that you shake, which makes a magnet move inside a coil and generate a little amount of power?
Do they actually work? Guys have found ordinary batteries hidden inside!
I tried shaking one in the store for a long time and I thought my arm was going to fall off. Then its LED was bright for a moment but quickly got dimmer and dimmer until it couldn't be seen after a few seconds. It was useless.

i;m form macedonia here sell a shake light in tv they workin fine but they are expensive for our standard but here sell and copies they not working fine they have batteries but they on tv also have batteries but when its shaked they are charge batteries

SORRY FOR MY BAD ENGLISH

On TV the "shake light" is a cartoon, it is not real.

i agree with audioguru., these shake lights are all gimicks. i got one and when i took it apart i found 2 3V coin cells in it that powered the LED. even if they used a rechargable type battery as the power source they would need atleast a 3.6V battery to power a white led. to charge the battery u need more than 3.6V DC. remember when u shake the torch u generated electricity but its AC (as the magnet moves in and out of the coil, thats faradays principle) so u need a rectifier to convert it to DC. but u also need to keep in mind the drop across a rectifier diode (nom. 0.6V for Si and 0.3V for Ge or Schottky) so u need an AC source of min 5V considering which the coil size will be quite large. if u use thinnner guage for the coil, u lose on the current side as the coil will give u voltage but the current will be too low to charge the battery. also since the voltage generated is directly proportional to rate of change of flux, i don't think that just by moving ur arm u can get sucha  high voltage. i've heard of some using very high capacity capacitors (more than 1 Farad) which are also known as gold caps, but they are just dc to dc converter circuits which steps up the voltage from small 3V cell to charge the cap and the use it to illuminate a led. ;)

I know what!
Shake it really fast, like at about 100Hz then it would make enough current to charge a capacitor or a battery. ;D

Hi,

If you need a battery less torch it’s much better to use an old stepper motor and a few diodes or rectifiers and some bright LEDs. It’s possible to charge some Ni-Cads with the stepper or if you need some backup and don’t want rechargeable cells you can use a Gold-cap or two! Almost any old stepper will work fine for this!

If you need a battery less torch it’s much better to use an old stepper motor

Hi Ante,
What will turn the stepper motor?
Windmill? Hand crank with gears?

Hi AG,

There are many ways you can turn the stepper. If it has a belt wheel it’s enough to turn it between your thumb and index finger. A small crank will work fine too, windmill, gears or rack and pinion with a spring! There are endless possibilities!
Even a small stepper generates a fair amount of power, if you got one in your junkbox try turning it with your fingers and then short all the wires together and try to turn it! ;D

Some use capacitors and some are fakes.
Here is an article on the subject.

http://www.gogreen.ie/squeezetorch/dynamotorchreview.htm

Hi Ante!

short all the wires together and try to turn it!

I did it with a bipolar one but the motor spined as easily as before.

Hi Ante!


I did it with a bipolar one but the motor spined as easily as before.

Then you have a faulty stepper motor or some other kind of motor! Stepper motors will even whiteout shorting the wires have clearly noticeable steps, and when shorting the leads it will be very sluggish! Unless of curse the magnets or the windings are gone, then it will spin easy!

Hi AG,

After some research I found this article in EPE 10-2000:
at page 724 -
[attachment deleted by admin]

And, sort of an update or overall mod here in EPE 03-2003:
These are truly battery less torches!

03-2003.pdf

Hi Ante,
That is a cranked torch without a crank.
Do you just twist the shaft back and forth about 180 degrees?

Hi AG,

Yes, just twist it between you fingers will do the job!

Then you have a faulty stepper motor or some other kind of motor! Stepper motors will even whiteout shorting the wires have clearly noticeable steps, and when shorting the leads it will be very sluggish! Unless of curse the magnets or the windings are gone, then it will spin easy!

Yes my stepper motor whiteout shorting the wires have clearly noticeable steps. I have experienced difficulty in spinning the motor while on. But just shortning the wires has no effect. Ante have you experienced it yourself?

Yes, I have tested many steppers this way to determine the suitability to generate power. Not every stepper becomes a good alternator but every one I have tried so far has a noticeable inertia when shorted.

Here is something that was found by accident.

http://www.circuitdb.com/show.php?cid=46

Thanks John, interesting!

I noticed that it has the same author as the two articles I posted earlier, he must be an expert in reusing steppers! ;D