Equipmet for my master thesis was enough to make ultrasonic levitation setup. So I tried to levitate light styrofoam pieces by ultrasonic waves.
You can find publication ( my MSc thesis ) by clicking on link below:
And you can find my master thesis(Turkish) below
28Khz Ultrasound is generated by piezoelectric transducer. To reflect sound waves I used PCB. As holder I used furniture leg and threaded rod. I squeezed PCB between two screw nuts and move up and down to find right position. When PCB fits on right position, distance between transducer and PCB will be multiple of sound wave’s wavelength. Then standing waves will occure. There will be high pressure and low pressure points between transducer and PCB. Particles will be trapped in low pressure points.
You can watch video below:
PIC based circuit generated 28Khz square wave, and I powered 28Khz Piezoelectric transducer by MOSFET IRFP250N and drive it by totem pole circuit.
Signal generator, totem pole driver, Mosfet+Heatsink(with fan) + Transformer
As Transformer, I used transformer removed from 250W SMPS computer power supply. Transformer has 220V input and 12V output. I used 12V as premier, 220V as seconder.
Transformer Piezoelectric Transducers
Totem Pole circuit is important for driving MOSFET. Even though MOSFET’s gate behave like capacitor, when frequency increases, gate capacitor is charging-decharging and behaves like draining current. PIC itself is not able to supply such current.
Totem Pole driver circuit (BD139 and BD140) with MOSFET IRFP250N