The piezoelectric-magnetic hammer

[Rapadura]

High efficiency piezoelectric generators using resonance:

http://www.freshpatents.com/-dt20090611ptan20090146534.php

http://www.ieeexplore.ieee.org/iel5/6171/16493/00762301.pdf?arnumber=762301

Could we activate that electromagnet for 50 milliseconds with the output power of the piezos?

[Rapadura]

Maybe my hammer can have wires wrapped in it, forming a coil. And we can place a static ring magnet at its side while it's moving up and down, something like the opposite of this video:

http://www.youtube.com/watch?v=xUxGqG8u-ME

Obviously, the effect has to be the same, don't matter what is moving, the ring magnet or the coil.

So, now we can have electricity generation in three points: the upper piezo, the lower piezo, and in the moving coil.

[Rapadura]

See:

http://www.youtube.com/watch?v=R9QrpwCp9pU

Can someone explain what is happening in this video? It's a little bit confusing, and the description is enigmatic: "piezo, electromagnet feedback".

[Rapadura]

Multilayer piezoelectric energy scavenger for large current generation:

http://www.springerlink.com/content/9v23732061q6847t/

"The piezoelectric material has been usually considered as a high voltage and low current source. When charging current into the thin film battery or supercapacitor, a larger current is needed to shorten the charging time. In order to increase the current in the piezoelectric energy harvesting, multilayer ceramics were fabricated. N-layer multilayer ceramics decreased the voltage but increased the current N times. The impedance of the multilayer ceramics are matched to 1 kΩ which is similar to the impedance of general electrical devices."

[Rapadura]

Someone knows how many volts and amps we need to pulse in a small coil to make it in a electromagnet capable of attract a small neodymium magnet 5 centimeters away?