Calibration of smartphone-based devices for noise exposure monitoring: Methodology, uncertainties of measurement and implementation

Abstract

Standardized noise exposure campaigns face challenges such as high cost of instrumentation and other difficulties associated with practical deployment in the field. Our ongoing research evaluates the suitability of an alternate solution based on smartphone sensing: the occupational noise exposure and its associated measurement uncertainties are estimated from a spatio-temporal analysis of smartphones' noise measurements and GPS data. This paper presents a laboratory free field calibration method for any noise dosimeter application on smartphone-based device. The proposed calibration procedure includes a frequency response linearization and an A-weighted sound level correction which is a function of the C-weighted minus A-weighted (C-A) noise levels values and A-weighted noise level. To ensure a realistic calibration, noise sources used during the measurement are based on the distribution of a referenced industrial noise database. The methodology of the measurements and the calculation of combined uncertainties associated with the measured correction values are detailed. The interpolation of calibration values and their implementation in an Android app, developed by the authors, is also presented. © 2013 Acoustical Society of America.