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Jochen’s DIY earthquake detector made from old hard drives – “…Most earthquake detectors use a heavy weight attached to a coil moving inside a magnetic field. Earth movement will cause the ground and attached magnet to move. The suspended weight and coil tend to stay stationary and hence a signal is generated. Elaborate electronic filters and damping needs to be employed to get a meaningful signal. My project avoids some of these problems by the use of ready made detectors with a low impedance and their own built in damping.” [via] – Link.


  • MadScott

    Great idea, but you have to be careful not to build in mechanical amplification by having the natural frequency (Fn) of the system close to that of the expected events…unless you want resonance, that is.

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