Ultrasonic Levitator

This is a simple print for a ultrasonic levitator, code and parts in this link:
https://www.heise.de/make/artikel/Einfacher-Ultraschall-Levitationsapparat-4022505.html

I modify the schematic adding a lm7805 for voltage regulator and a 470mf capacitor.
for adjust the distance use a long m5 screw with 3 nuts (all hexagonal)

in the pdf you have my pcb desing for lm 293d and arduino nano.