From magic to science, man has long dreamed about being able to manipulate objects from a distance. People have been able to push something using air or even sound waves for a while, but University of Bristol researcher Asier Marzo and colleagues have come up with a 3D-printable device that can not only repel small items, but can also attract them to the source.
It does this using an array of sound transducers arranged in a dome shape at the end of a wand. The acoustic tractor beam is also equipped with an Arduino Nano, a motor controller board, a DC-DC converter, and a LiPo battery, among some other easily accessible components.
Basically, an Arduino will generate 4 half-square signals at 5Vpp 40kHz with different phases. These signals get amplified to 25Vpp by the motor driver and fed into the transducers. A button pad can be used to change the phases so that the particle moves up and down. A battery (7.3V) powers the Arduino and the logic part of the motor driver. A DC-DC converter steps-up the 7.3V to 25V for the motor driver.
Aside from entertaining friends by levitating tiny pieces of plastic, the DIY tractor beams have many possible use cases, particularly in biological research. However, there are some limitations. Given the challenge of suspending objects more than half the wavelength of sound, the gadget can only trap things around a few millimeters in size.
Marzo and his team have published their project in the journal Applied Physics Letters, and shared step-by-step instructions so you could get started on building your own beam. You can read more on Phys.org as well.