We designed a very simple energy harvester made of a little magnet that moves inside a coil.

We have a vibrating environment moving at 12 Hz with 10 millimeters peak-to-peak. Our pcb will be attached to the vibrating table and will be potted to avoid problems to the components soldered onto the pcb.

Currently only a gyroscope, an accelerometer and a bluetooth module are on it.

The problems derived from the rectification are not the major issues.

Our PCB has to be attached to this vibrating table, that works 24/7. We realized that our energy harvester has to support ca 14 millions vibrations in just two weeks.


1 Answer 1


I'll assume your "10 mm amplitude" is peak to peak. The position can therefore be described as

   P = 5 sin(2π12t) [mm]


   P = 5 sin(ωt) [mm], where ω = 24π

The velocity is the first derivative of position:

   V = 5ω cos(ωt) [mm/s]

The acceleration is the second derivative of position and the first derivative of velocity:

   A = -5ω2 sin(ωt) [mm/s2]

Plugging in our value of ω, the maximum acceleration is

   Max A = 5ω2 mm/s2 = 5(24π)2 mm/s2 = 28,400 mm/s2 = 28.4 m/s2 = 2.9 g

3 g isn't that much. Of course you have to consider that this will be applied repetitively, but still, it should be possible to design something that can withstand many many 3 g cycles.

  • \$\begingroup\$ Thank you very much. The amplitude I was wrongly talking about is peak to peak, I'm going to update the post. My second question is: what measures should we follow to get this energy harvester to last two years 'always on'? \$\endgroup\$
    – ThreeState
    Commented Jan 13, 2016 at 12:32
  • \$\begingroup\$ @Three: That's a mechanical engineering question. \$\endgroup\$ Commented Jan 13, 2016 at 12:44
  • \$\begingroup\$ Do you think I have to move the question or make a separate one? \$\endgroup\$
    – ThreeState
    Commented Jan 13, 2016 at 12:46

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