I see that Goldmine has $0.99 40KHz transducers (until midnight.) Their "receiver" title just means that the freq is not matched to transceiver transducers. Time to try that ultrasound levitator with the "suction" feature. Need 24 transducers, two opposite-phase banks of 12 (with five having lagged phase.)
Arduino certainly not needed: try a quadrature drive, perhaps with adj. resonant series inductors to give a better match to low-z amplifier outputs.
Only problem is: the hemispherical support almost certainly requires a 2N/40KHz radius for standing waves. 3D print, or epoxy fiberglas on a sphere of the right dia.
No phase-array, so no moving your styro beads in three dimensions.
Heh, paint your styro bead black, for hoaxing a room-temp superconductor demo.
(((((((((((((((( ( ( ( ( (O) ) ) ) ) )))))))))))))))) William J. Beaty