Head-Shadow Effect Analysis by Portable Noise Sensing Module Embedded in Labor Helmet
More than 400 million people worldwide have suffered from hearing loss in recent years, among which the probability of laborers being exposed to occupational noise is five times more likely than normal people. Although there are occupational safety and health laws around the world to prevent hearing risks of laborers, most of the regulations have ignored the impact of Head-Shadow Effect (HSE). Therefore, this study emphasizes on the correlation between HSE and health of laborers by integrating existing relevant technologies to innovatively develop a Portable Noise Sensing Module (PNSM) from professors in Civil Engineering and Electrical Engineering. The PNSM consists of MEMS Microphone, Button battery, Digital Signal Processor and ZigBee wireless sensor. This study can measure and record the real-time Sound Pressure Levels of exposed noise in different directions by embedding PNSM on the front, left and right side of the labor helmet. In the feasibility verification part, this study intends to simulate construction site noise at different frequencies (200/300/400/3000 Hz) through Piezoelectric Buzzer. In order to analyze the correlation between Head-Shadow Effect and health, experiments were conducted on four variables including distance, angle, frequency and loudness of noise source. Reliability studies indicate that the PNSM performs reliably, it can detect noise coming from different directions in real time. Head-Shadow Effect showed significant correlation with hearing health. It is important to consider the Head-Shadow Effect when analyzing hearing risk in any different noise condition.
Keywords - Head-Shadow Effect, Hearing Risk, Labor Helmet, Occupational Health, Sensor.