Design and Development of a Digital Signal Processing System that Responds Automatically to an Audio Trigger Event

Abstract

This paper presents the development of a signal processing system that responds automatically to an audio trigger event. The audio trigger event, for example, can be a gun shot, and the system's response is to fire back at the source. The proposed system uses microcontrollers to digitally process audio signals coming from the audio trigger. Once the event is detected, the location of that source relative to the base location is estimated and retaliatory measures are automatically activated by the system. In our study, gunshot sounds are replaced by recorded audio tones and the retaliatory mechanism consists of a Nerf dart being fired toward the sound source. Sound localization is achieved via time stamping the digitized microphone signals. With an array of microphones, angular components as well as radial components can be determined. Servo motors are used to control the turret type mechanism for firing back Nerf darts to the source. The project has potentials for both lethal and non-lethal responses to a firearm discharge. The work is based on a 2013 senior undergraduate capstone project.