[luciano furtado]

The coil pickups may be the primary winding of a common power transformer whose nucleus has been removed.
The mechanical system should have a weight on its tip and a magnet that will generate, by induction, the tension signal to move inside the coil.
The oscilloscope should be set to a frequency scan consistent with the phenomenon to be observed, usually a low frequency (0.1 to 10 Hz).
This same circuitry can be coupled to an analog / digital converter (ADC) so that the recorded data can be transferred to a computer, obtaining a more sophisticated analysis of fenômeno.Uma variation of the circuit can be obtained with a pendulum , in which case your line is attached is a small magnet, as shown.