Developing a Low-Cost Miniature Personal Noise Dosimeter

DESCRIPTION (provided by applicant): The objective of the proposed research is to develop a miniature, low cost, user-friendly personal sound level dosimeter. This dosimeter will fill the need of those consumers whose work-related or recreation-related act ivities expose her or him to sounds that might cause hearing loss. In contrast to typical dosimeter use, in which control of the dosimeter and its data lies with a manager or clinician, the wearer of the proposed dosimeter will control it and receive its d ata output, thereby facilitating the wearer's understanding and appreciation of his or her sound exposure dose. The proposed dosimeter will also be capable of functioning as a sound level meter for instantaneous monitoring of sound levels. The feasibility of the proposed development will be tested in Phase 1 by demonstrating that a miniature, low-cost dosimeter can meet the ANSI S1.25-1991 standard for such devices. Preliminary tests with a microcontroller-based system suggest that approximations to the sta ndard dosimeter function blocks can be made without sacrificing the operating tolerances specified by the ANSI standard. Other tests with inexpensive microphone capsules show that drift due to temperature and humidity is within acceptable tolerances. By re ducing the number of features, simplifying signal processing, and using inexpensive microphones and a microcontroller, a low-cost miniature dosimeter should be realizable. In Phase I, a prototype dosimeter will be developed around a Texas Instruments embed ded controller and LCD display powered by a single lithium cell. After testing to verify that the ANSI standard has been met, a limited set of field tests, with wearers using both the proposed prototype and a commercial dosimeter, will be carried out to fu rther validate the overall dosimetry performance of the prototype. Future work in Phase II will focus on performance improvements and making the dosiemeter production-ready through (a) reductions in size and power consumption; (b) ergonomic design of contr ols, (c) more informative and user-friendly displays; (d) possible tactile or visual feedback; and (e) incorporation of more accurate measures of risk from impulsive noise exposure. The proposed dosimeter (plus sound level meter) is intended to provide a n accurate measure of sound exposure dose (or level) that is both affordable and meaningful for consumers. The eventual product will be sold via internet and catalog channels aimed at industries that are not actively monitored by OSHA (e.g., construction, drilling, agriculture, music) and noisy recreational activities (e.g., shooting, motor sports, music).