What are reasons to consider when choosing between linear resonant actuators (LRA) and eccentric rotating masses (ERM)?

I'm sketching on a remote-controlled vibrator sex toy with variable frequency, but didn't manage to find an existing easily hackable one, so I'm looking at making one from scratch.

  • \$\begingroup\$ Perhaps foil-type shavers employ linear resonant actuators technology. Hackable? \$\endgroup\$
    – glen_geek
    Feb 27, 2019 at 17:30
  • \$\begingroup\$ Two reasons would be the selection of axes you wish the device to vibrate on. An ERM is incapable of producing vibration on a single axis. A combination of multiple motors may be desirable. All very simple to build and experiment with, other than the wifi communication. You'll want to do some investigation into body safe plastics/materials though. This is not a simple 3D printing job. \$\endgroup\$
    – K H
    Feb 28, 2019 at 2:24

1 Answer 1


In general, LRA's only work at small bandwidth of frequencies (typically, 180-220 Hz). The beauty is, the frequency doesn't depend on the amplitude. You can make it buzz harder without buzzing faster.

ERM's have frequency and amplitude coupled. The faster you spin, the harder it buzzes.

Depending on your frequency range, either one will work for your application.


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