Abstract: The Ellis lab investigates a variety of non-Hermitian systems where active manipulation of the equations of motion can be used to engineer novel behavior. The instrumentation behind such manipulation and study of high-frequency oscillators is the focus of this research; we assess the efficacy of using a Raspberry Pi with external audio card connected to piezoelectric transducers to serve as a low-cost, easily reproducible, and versatile feedback loop. By developing our own software to interface with the Advanced Linux Sound Architecture, we apply our inexpensive hardware to sustain an effectively undamped gyration of an aluminium bar at 7 kHz for many thousands of cycles. Features of our implementation include a matrix of finely adjustable gain parameters, recursive linear filtering to provide sub-sample control over phase shift and potential band-pass filtering, and concurrent data acquisition from two channels without interrupting the feedback loop. Overall, we demonstrate that software-based oscillation control strategies are feasible and effective at kilohertz frequencies without the need for costly hardware.
ihuang-posterLive Poster Session:
Thursday, July 29th 1:15-2:30pm EDT