Project Description:

Temperature is significant for many applications such as weather forecasting, precision agriculture, and building management. Though measuring ambient temperature is often deemed as an easy job, collecting large-scale temperature readings in real-time is still a formidable task. Recent blooming of network ready (mobile) devices and the subsequent mobile crowdsourcing applications do offer an opportunity to accomplish this task, yet equipping commodity devices with ambient temperature sensing capability is highly non-trivial and hence has never been achieved. In this paper, we propose Acoustic Thermometer (AcuTe) as the first ambient temperature sensor empowered by a single commodity smartphone. AcuTe utilizes on-board dual microphones to estimate air-borne sound propagation speed, thereby deriving ambient temperature. To accurately estimate sound propagation speed, we leverage the phase of chirp signals, circumventing the low sample rate on commodity hardware. In addition, to prevent disruptive audible transmissions, we convert chirp signals into white noises and propose a pipeline of signal processing algorithms to denoise received samples. Furthermore, we propose to use both structure-borne and air-borne propagations to address the multipath problem. As a mobile, economical, highly accurate sensor, AcuTe may potentially enable many relevant applications, in particular large-scale indoor/outdoor temperature monitoring in real-time. We conduct extensive experiments on AcuTe; the results demonstrate a robust performance, a median accuracy of 0.3 degree even at a varying humidity level, and the ability to conduct distributed temperature sensing in real-time.

Acknowledgement:

• This project is filed on 27 August 2020 and accorded Singapore provisional patent application number 10202008235Y. This project is under NTUITIVE License Agreement. For more information please visit our git repository

  People:

  • Dr. Chao Cai (Research Fellow, Computer Science & Engineering) - Nanyang Technological University
  • Henglin Pu (UG student, Electronic Information & Engineering) - HUST
  • Liyuan Ye (Master student, Electronic Information & Engineering) - HUST
  • Dr. Jun Luo (Associate Professor, Computer Science & Engineering) - Nanyang Technological University

  Related Publications:

• [1] C. Cai, Z. Che, H. Pu, L. Ye, M. Hu, J. Luo, "AcuTe: Acoustic Thermometer Empowered by a Single Smartphone", in ACM Sensys,2020
• [2] C. Cai, H. Pu, M. Hu, R. Zheng, and J. Luo, "SST: Software Sonic Thermometer on Acoustic-enabled IoT Devices", in IEEE Transactions on Mobile Computing, 2020
• [3] H. Pu, C. Cai, M. Hu, and R. Zheng. "Non-contact thermal sensing on acoustic-enabled IoT devices", in ACM UbiComp/ISWC ’19 Adjunct.
• [4] C. Cai, H. Pu, L. Ye, and J. Luo. "Active Acoustic Sensing for Hearing Temperature under Acoustic Interference", in ACM UbiComp/ISWC ’19 Adjunct.