Levitron on the Hall sensor SS441A

A simple levitron, consisting of only six electronic components. A small magnet hangs in the air and is not attached to anything. The magnet is motionless, although in fact it oscillates up and down, but we do not see them, because the frequency of these oscillations is high

The principle of operation is as follows: when the supply voltage is applied, the current goes through the coil-electromagnet, creating a magnetic field, to which a small permanent magnet is attracted. But between the electromagnet and the permanent magnet there is a Hall sensor. When the permanent magnet enters the Hall sensor's range, the sensor blocks the operation of the field-effect transistor and the electromagnet is switched off, while the permanent magnet falls down. As soon as the field of the permanent magnet disappears from the Hall sensor's range, the electromagnet turns on again and again attracts it to itself. All these falls and attractions are repeated several tens or hundreds of times per second, this is not visible and it seems that the magnet hangs motionless in the air.

The coil contains 500 turns of wire with a diameter of approximately 0.3-0.5 mm, wound on a tube with a diameter of 7 mm. A metal bolt must be inserted into the tube to increase the electromagnetic field of the coil

The Hall sensor needs to be unipolar type SS441A. It needs to be placed between the coil and the magnet

When powered from 7.5 V, the current consumption should not exceed 0.5–0.6 A. The signal can be measured on the coil itself; it will be rectangular in shape with a frequency of about 125 Hz

Glue a piece of paper to the magnet, otherwise the magnet will twitch in the air and will be unstable