In order to conduct study, I need to produce controlled vibrations with amplitude (maximum) approx 200 um (micro) at frequency between (100-150) Hz. Vibration amplitude must be controlled with input voltage (Battery operable) while frequency remain constant.

I tried many things :

1) Eccentric Motor - frequency and amplitude, both varied with voltage.

2) Solenoid - difficult to control with voltage. (If any way exists, please suggest me).

3) Voice Coil Motor - Its very costly, I need solution around 10-20 $ max. as project constraint.

4) Linear Resonant Actuator - It is the best solution, but I am not able to find any LRA which can produce vibrations in um (micro metre).

Please suggest me any product exists or ways to produce controlled vibrations.

  • 1
    $\begingroup$ By "voice coil motor" do you mean the motor from a computer disk drive? The voice coil from a cheap loudspeaker might work just as well, and be in your price range. $\endgroup$
    – alephzero
    Sep 22, 2018 at 16:28
  • $\begingroup$ voice coil motor works on the same principle as speaker works. $\endgroup$ Sep 22, 2018 at 19:10
  • 2
    $\begingroup$ Piezoelectric transducers can used to excite the waveforms you are talking about. $\endgroup$ Sep 23, 2018 at 23:32
  • $\begingroup$ piezoelectric transducers are very costly. Can you suggest one, if its available cheap online. Thanks in advance. $\endgroup$ Oct 8, 2018 at 13:39
  • $\begingroup$ Piezo disc transducers are quite cheap: amazon.com/3-pack-Piezoelectric-Elements-Contact-Pickups/dp/… $\endgroup$
    – Eric S
    Oct 22, 2018 at 16:04

1 Answer 1


You can make an AC electromagnet pretty cheaply. Wrap some enamel coated wire around a steel bolt. Then get a steel cantilever beam with a resonant frequency equal to the frequency of interest. Place the magnet just under the tip of the beam and drive it with an ac voltage at the resonant frequency. 200 um should be achievable with a few volts if you have a sufficiently big magnet.


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