MAGNET LEVITATION EXPERIMENT

I use a coil (450 r-0.5 mm) a hall sensor inside the coil and a mosfet as a switch for the current to the coil. The diode protects the mosfet from the back emf of the coil. A resistance controls the current to the base of the mosfet. The coil attracts the magnet , then when the supply stops the magnet begin to fall , the supply to the coil begin again and attracts the magnet again .This happens many times per second and the magnet seems to stay in the same place.
I try to find a shematic for the opposite effect. The object that levitates to be up and the electromagnet to be down.I' ve seen a system of 4 coils and 2 hall sensor but I cannot find it's shematic .Doew anyone can help? Thank you. You can watch this experiment here: https://youtu.be/Al7rRysqQH8

Ingenious use of the Hall sensor. Kind of the "Segway" of magnetic levitation, eh? :hattip:

K and J Magnetics had a blog post a while back where they built the inverted setup with ratiometric sensors, but they didn't provide a detailed schematic. I get quite a few hits when searching for "repulsive electromagnetic levitation schematic," but there are about as many ways to go about doing it as there are people building them.

I 've found two shematics but there are a few correctionts from other vewers so i am not so sure that they are right.

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Originally Posted by mariost

I 've found two shematics but there are a few correctionts from other vewers so i am not so sure that they are right.

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I wonder if the circuitry commonly used for switching power supplies couldn't be used – or adapted – to work with that set up? (Just a thought.)

You could easily feed the sensor into a small microcontroller like an LPC80x series or even an STM8 series. That would smooth out the detections and output a PWM signal to drive the coil. You'd have at least part of a PID loop in the processor.

You could also sense the location of a shiny object like a ball bearing with an infra-red photo beam. That would give you an analog position of the ball and make smooth control easier.