This system uses an electromagnet to levitate a small magnet in midair. The small magnet levitates in the air indefinitely without any disturbance. The air gap is about 2 cm (3/4"). The supply voltage is 5 V and the supply current is about 0.3 A.
The vertical position of the levitating magnet is measured using a linear Hall effect sensor and the current in the electromagnet is actively controlled using a dsPIC30F3012 digital signal processor.
Three push buttons are included to adjust the vertical position of the levitating magnet and to apply a sinusoidal, square or sawtooth reference signal. Both the amplitude and frequency of the reference signal can be adjusted using the push buttons.