Want to build a magnetic levitator in under two hours? With a total of 7 parts, including the coil, it just cannot get simpler than what [How-ToDo] shows here! It is not only an extremely simple circuit, it also has the advantage of using only discrete components: a MOSFET, hall effect sensor, diode and two resistors, that’s it.
The circuit works by sensing the position of the levitating magnet, using the hall effect sensor , then turns the coil on and off in response via the MOSFET. The magnet moves upwards when the coil is energized and falls down when it is not. This adjustment is made hundreds of times a second, and the result is that the magnets stays floating in mid air.
This is the kind of project that can make a kid get interested in science: it combines easy construction with visually amazing behavior, and can teach you basic concepts (electromagnetism and basic electronics in this case). Excellent for a school project.