Researchers Develop Home Acoustic Levitator

A research team at the University of Bristol, UK, has developed a relatively cheap and small acoustic levitator that is capable of holding samples of interest in mid-air.

The TinyLev system is composed of the driver board and the single-axis levitator with 72 transducers (arranged as two surfaces, each containing 36 transducers); expanded polystyrene (EPS) particles are trapped at its nodes. Image credit: Marzo et al, doi: 10.1063/1.4989995.

“Acoustic levitation uses powerful acoustic waves to push particles from all directions and trap them in mid-air,” explained team leader Dr. Asier Marzo and colleagues.

“By using ultrasound it is possible to use powerful vibrations without causing any harm to humans.”

Dr. Marzo and co-authors constructed a single-axis levitator from low-cost off-the-shelf components and 3D printed sections.

Dubbed TinyLev, the levitator can trap objects above 2.2 g/cm³ density and 4 mm in diameter (water, fused-silica spheres, small insects, electronic components) whilst consuming 10 W of input power.

The device is safe to use, robust against temperature or humidity changes, and can operate for extensive periods of time, enabling experiments that were not possible before.

“Levitating samples in mid-air can improve diagnosis from blood samples and detection of the structure of molecules,” Dr. Marzo said.

“Usually a sample on a microscope slide is illuminated with X-rays, lasers or another type of radiation so the reflected radiation can be analyzed.”

“However, no matter how transparent the microscope slide is, it will always interfere with the test. On the contrary, if the sample is levitated, all the reflections are going to be from the sample.”

The researchers also developed an instruction pack for those wanting to assemble their own levitator at home or school.

“Acoustic levitation has been explored in hundreds of studies for applications in pharmaceuticals, biology or biomaterials. It holds the promise of supporting innovative and ground-breaking processes,” said Dr. Marzo, lead author of the paper published in the journal Review of Scientific Instruments.

“However, historically levitators have been restricted to a small number of research labs because they needed to be custom-made, carefully tuned and required high-voltage.”

“Now, not only scientists but also students can build their own levitator at home or school to experiment and try new applications of acoustic levitation.”

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Asier Marzo et al. 2017. TinyLev: A multi-emitter single-axis acoustic levitator. Review of Scientific Instruments 88: 085105; doi: 10.1063/1.4989995