Emergency Evacuation Guiding System Using Changeable Sound Directivity

This paper introduces a method to design an emergency guiding system which uses changeable directivity based on a speaker array. In general, existing emergency evacuation guiding systems depend on visual techniques like emergency lights or LEDs. Actually people in the case of fire emergency condition may not obtain a range of view because of smoke from the fire. To cope with this problem, the guiding system based on the visual techniques need to be replaced with the systems using sound from a number of speakers proposed in this paper. A fundamental method to implement the sound directivity needs to use a speaker array which consists of many speakers in a line. In this paper, we can obtain the sound directivity using the modified fundamental method which will work in several shaped buildings. We use a modified speaker array system to make a time delay and differential frequency based on Doppler Effect and Haas Effect. For more accurate direction information, a servo motor is used to each speaker of the speaker array to make sound directivity physically. In this case all speakers are serially connected for audio signal transmission in a serial fashion to achieve convenient speaker installation. The system with more accurate direction proposed in this paper has been designed and tested as follows; first, we study to find the appropriate frequency range and sound pressure level in a noisy emergency environment. Second we verify the efficiency of our proposed evacuation guiding system with sample groups of people in a virtual emergency studio environment. As conclusion, the system proposed in this paper has achievements, such as increasing evacuation rate under emergency conditions, and serial transmission of audio signal for easy maintenance and low installation cost.