A single-sided sonic tractor beam that can levitate objects without the need for complex phase-shifting electronics has been developed by researchers in the UK. Instead the device uses an acoustic lens, which can be made with a set of 3D-printed cells or a shaped surface to create the required acoustic fields. The team says that the device can be made for less than $90 with readily available components and a 3D printer, and has released instructions and a YouTube video explaining how.
In 2015, Bruce Drinkwater of the University of Bristol and colleagues developed a single-sided tractor beam that used sound waves to levitate, rotate and move objects. The device used an array of 64 off-the-shelf loudspeakers controlled by complex phase-shifting electronics. The array created 3D fields of sound – acoustic holograms – that could surround and trap objects. By controlling the output of the speakers, the acoustic holograms could be adjusted to hold, rotate and move objects – small polystyrene particles – in mid-air.
To read more and view the video, click here.