A personal dosimeter for smartphones

Abstract

Smartphones are increasingly popular because of their portability and multifunction capabilities, and they are often used as a personal music player by their users-adolescents and adults alike Studies have shown that there is prevalence of hearing damage among smartphone/music player users, particularly adolescents, that excessively listen to music through earphones/headphones. Further, they are at risk of suffering permanent noise-induced hearing loss in later life if they have prolonged exposure to sound/noise exceeding the recommended safe noise dosage. Despite the hearing loss risk, most music player users underestimate the importance of hearing and the dangers of excessive noise exposure, and regularly exceed the safe noise dosage by listening to loud music from their smartphone/music players. Therefore, it is imperative that the smartphone/music player user can be made aware of his/her noise dosage to prevent him/her from exceeding the safe noise dosage.

In this Final Year Project (FYP), we developed the first personal (noise) dosimeter for iPhonesa popular smartphone with a large global market shares. Our dosimeter has a small form factormuch smaller than conventional bulky dosimeters for industrial use, and it can be easily plugged into the audio socket of the iPhone, while still providing the usual microphone input and the audio output to the earphone. Further, it is convenient without the need for batteries as it is self-powered by drawing/harvesting energy from the iPhone. The hardware and the embedded software (noise dosimeter algorithm) have been designed so that they draw low energy and this energy can be adequately provided by the iPhone itself. The dosimeter samples the audio output to the earphone, and calculates the user‟s noise dosage and also the sound pressure level. It will alert the user by blinking an LED when the noise dosage or the sound pressure level has exceeded the safe threshold value. The noise dosage algorithm takes into consideration the (iPhone) earphone characteristics to improve the accuracy. The dosimeter has been verified by experimental measurements.