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I was wondering if you have something that vibrates , is there any way that you can make some power out of it?

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    \$\begingroup\$ You want to google on energy harvesting, search in the appnotes from Linear Technology or similar. They have ICs for it. \$\endgroup\$
    – pipe
    Feb 15, 2016 at 15:01
  • \$\begingroup\$ Piezoelectrical device \$\endgroup\$
    – ElectronS
    Feb 15, 2016 at 15:32

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There is a wide range of materials that will produce electrical charges in response to mechanical stress. While the voltage produced this way can be quite high (thousands of volts), overall power output is typically small.

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  • \$\begingroup\$ what i would like to accomplish is charge a battery , but i reckon i wont have any luck... what do you think? Could someone charge his phone while riding his skateboard? which is a very vibrant thing when riding on tarmac for example.. \$\endgroup\$
    – Ml Ck
    Feb 15, 2016 at 14:41
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    \$\begingroup\$ Yep, your idea is pretty much doomed: you'll end up with orders of magnitude less power than needed, even if your piezo crystal or coil+magnet are as large as your skateboard. BTW, next time you should mention a little bit of context in the question itself, it's easier to understand it that way. Knowing the context, a dynamo attached to a wheel comes to mind. \$\endgroup\$ Feb 15, 2016 at 14:44
  • \$\begingroup\$ yea thanks for the suggestion about the dynamo, i actually have thought of all the alternatives or the more obvious ones, so i thought id ask about vibration, still i think that a small thing moving a 90KG should be able to produce some energy , so much goes to heat :) \$\endgroup\$
    – Ml Ck
    Feb 16, 2016 at 6:58
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Two obvious methods come to mind:

  1. Piezoelectric. Something that exhibits the piezoelectric effect, like a quartz crystal, can move charges around as a function of strain. Some microcphones are based on this principle, as are some electronic barbecue grill igniters. In the microphone, sound wave vibrate the crystal, which produces a voltage proportional to the sound waves. In the igniter, something whacks the crystal hard to make a higher but short voltage.

  2. Electrodynamic. The alternator in your car, the generators in a power plant, and a type of microcphone called "dynamic" all work on this principal. In the case of the microphone, it is like a small speaker in reverse. A diaphram is moved by the changing air pressure, which moves a coil within the magnetic field of a permanent magnet. The resulting small signals (usually a millivolt or a few) are proportional to the sound.

    I have also seen flashlights based on this principle. They have a heavy permanent magnet that can slide inside a coil. You shake the flashlight to move the magnet back and forth, which causes the coil to produce electric power, which is stored in a capacitor that powers the light for a minute or a few minutes from full charge.

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Yes, you can use the reverse of the principle that a speaker uses. If you move a conductor (e.g. wire) through a magnetic field, a voltage is induced. To induce enough voltage to be useful, a coil of wire can be wound and made to move in a magnetic field. The lines of flux must radiate from the middle of the coil to the outside, so that the field lines are perpendicular to the windings. An old speaker drive unit will do this job for a small amount of power. You then need to arrange the mechanical setup so that the vibrating thing causes the coil to move relative to the magnet.

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  • \$\begingroup\$ i understand that speaker movement can get some movement compared to actual vibration... or you are not talking about the cone movement..? \$\endgroup\$
    – Ml Ck
    Feb 15, 2016 at 14:39
  • \$\begingroup\$ Yes, this is the movement of the cone, of at least the centre attachment point of the cone, with respect to the frame of the speaker. This generates a voltage at the speaker terminals by the reverse of the process that produces movement of the cone when a voltage is applied to the terminals. \$\endgroup\$ Feb 15, 2016 at 15:40

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