Acoustic Particle Levitator

Built an 8x8 phased array of ultrasonic piezo transducers and beamformed it to levitate small particles in midair. The project served as a proof-of-concept for future neuromodulation work using pMUT arrays. Each element was driven at 40kHz, 15Vpp using a driver board from Upna Lab with a ton of dual MOSFET-driver ICs. We're migrating to an FPGA-based control system for tighter phase alignment and timing guarantees. To verify that the array was actually focusing sound where I thought it was, I built an optical Schlieren imaging setup to visualize the acoustic pressure field. It worked spectacularly for heat and… less spectacularly for ultrasound (mainly a consequence of our camera and mirror quality). We ended up using a hydrophone in a fish tank mounted on a 3D-printer (because that's a normal solution to this problem). Org: Liwei Lin Lab

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