An affordable open-source DAQ system for real-time multi-channel acoustic signal processing

Abstract

Here, we share our unique data acquisition (DAQ) system, using an open-source ARM microcontroller SoC, the Teensy 3.6 (pjrc.com), for underwater acoustic beam-forming applications, especially for use on autonomous vehicles..

Modern advances in low-cost, low-power "system on a chip" (SoC) devices are currently enabling unprecedented computational power, and some state-of-the-art are particularly well-constructed for acoustic signal processing applications. While we focus on underwater acoustics here, these systems are equally powerful for measurement of many processes in the <100kHz range. Our device, roughly the size of a stick of gum and costing ~$35 USD, performs "end-to-end" acoustic signal processing entirely onboard the embedded system, and is capable of sampling rates in the 100s of kHz of multiple channels concurrently, extremely fast onboard Fourier calculations, as well as dynamic interaction with other devices via external digital communications. This system is also a fraction of the size and power consumption of more well-known open source SoC systems (e.g. Rasperry Pi) and much more powerful than other open-source microcontrollers such as Arduino.

Here, we present our results of performance experiments, demonstrating the speed and accuracy of sampling and processing audio-frequency acoustic signal processing, for a wide variety of signals and sampling regimes. We will demonstrate trade-offs between sampling rates and resolutions for accuracy and speed at desired frequencies, and how these may be dynamically managed by autonomous systems. Finally we will share some of our work, towards underwater acoustic beam-forming using 3D acoustic vector sensors, and our implementation of these devices on unmanned autonomous vehicles, such as the "AquaQuad" quadcopter.