Ultrasound Array for Acoustic Levitation

Overview:

We created a set of two ultrasound transducer arrays that can be precisely phase-controlled for beam forming, which together can levitate small particles using ultrasound standing waves. 

Description:

Two connected PCBs, each with an 8x8 array of 40kHz ultrasonic transducers, are arranged in opposing fashion and can acoustically levitate small particles.  

Beamforming is achieved by precise phase and amplitude modulation (32 phase divisions for 40kHz transducers), controlled by one unified FPGA across the two boards.

With two phase controlled transducer arrays, standing waves can be created, the nodes of which can cause small particles to levitate. Through precise phase and amplitude control we can create various patterns and maps in 3D space. 

The boards are made portable by USB Power delivery, and leverages a reinforced signal chain to ensure signal integrity between boards.

Our project has taken heavy inspiration from the SonicSurface project, with our emphasis on recreating the project from scratch and making the product a fully stand-alone device without the need of external precise power supplies or FPGAs. 

Features:

• Opposing two-board design for creating controlled standing waves

• 8x8 Transducer Array on each board

• FPGA controls both boards at 32 phase-divisions for 40kHz ultrasound waves

• Supports Phase and Amplitude modulation for beam forming

• ESP32 WROOM 32E and ESP32S2 microcontroller compatibility

• Power:

  • USBPD through USBPD to deliver 20V with a max of 60W

  • Buck-Boost converter for 20V to 18V for transducers

  • Buck converters for 3.3V and 5V for digital logic

  • LDOs for additional FPGA supply voltages