Research On An Embedded Emergency Communication System

With the progress and development of society,outdoor adventure activities are prevalent,however,there exist still certain safety problems,such as getting lost and other reasons that can lead to loss of personnel,so portable emergency communication equipment is widely used.Walkie-talkie is a common means of communication for outdoor adventure,but it needs to switch between listening and speaking through buttons.And conflicts between members are likely to be caused by pressing buttons.Other emergency communication equipment is currently not highly integrated and expensive.It less considers the information sharing function when the distance is far away.Therefore,it is necessary to design a portable emergency communication system to solve the deficiencies of existing communication facilities.This thesis designs and implements an embedded emergency communication system,which is mainly composed of a full-duplex multi-party cooperative voice communication subsystem,a personnel monitoring subsystem,and a human-machine interaction subsystem.It supports voice communication,positioning and human-machine interaction.Among them,the full-duplex multi-party cooperative voice communication subsystem is mainly responsible for the establishment of Ad-hoc network and the realization of multi-party cooperative voice communication.The personnel monitoring subsystem is mainly responsible for the acquisition of sensor data,information sharing,and early warning functions.And the human-machine interaction subsystem uses buttons and LCD display screens for user status input and display.In order to achieve the above functions,this system uses the Feiling OK6818 development board as the hardware development platform,the external rtl8180 wireless Wi-Fi module and the Openedv ATK-LORA-01 wireless module provide voice communication and information sharing services respectively.The graphical interface development tool Qt is used for interface display,the Linux operating system is used as a software development platform.When numbers gather,the system uses full-duplex multi-party cooperative voice communication subsystem for voice communication,using Speex audio coding method to compress the audio data,and transmitting the audio data through the RTP Real-time Transmission Protocol.When members are scattered,the system use the personnel monitoring subsystem to share information.The multi-channel monitoring is completely based on the epoll mechanism,the data collected by the sensor is transmitted through LoRa technology,and the communication distance between members is calculated to complete the warning prompt.At the same time,each subsystem completes inter-process communication through UNIX Domain Socket.The test results show that the embedded emergency communication system designed and implemented in this paper can realize real-time and clear multi-party collaborative voice communication,with good communication quality.Sensor data can be collected and transmitted in real time,and the information sharing range can reach up to 1.5km,realizing location information sharing.At the same time,it is equipped with buttons and LCD display to realize status input and display,and meet the system requirements of embedded emergency communication.