11-03-2021, 04:46 PM
Two more things..
1) If you will replace the permanent magnet by a ferrite which is remagnetized at high frequencies you will not need the diodes. The ferrite is attracted by a coil with both current polarity.
2) The spring is itself a coil which should shrink when current of any polarity pass through it. I tried it just now, but the current is too low. A powerful signal generator can be used. The frequency can be determined by the smartphone from acceleration signal... An advantage of this technique is that the driving force should not depend on the oscillation amplitude.
....
1) If you will replace the permanent magnet by a ferrite which is remagnetized at high frequencies you will not need the diodes. The ferrite is attracted by a coil with both current polarity.
2) The spring is itself a coil which should shrink when current of any polarity pass through it. I tried it just now, but the current is too low. A powerful signal generator can be used. The frequency can be determined by the smartphone from acceleration signal... An advantage of this technique is that the driving force should not depend on the oscillation amplitude.
....