스마트 교통신호등 시스템 구현

Abstract

In this paper, we propose a smart traffic light system to perform the roles of existing pedestrian traffic lights, remaining time indicators, acoustic signals, and pedestrian operation signals. The proposed system consists of BLE beacon, mobile app, and server. The BLE beacon implemented hardware by interconnecting two BLE 4.2 modules on one PCB, and was built into the newly designed remaining time indicator. The BLE beacon periodically advertises a beacon frame through an advertisement channel. The beacon frame includes a traffic light ID, pedestrian traffic light related information, and remaining time information. The smart app performs the functions of a pedestrian traffic light and remaining time indicators by displaying the status (red/green) of the pedestrian traffic light and the remaining time of the current signal on the screen. The proposed system is an alternative that can solve the problem of acoustic signals. The smart app receives the beacon frame that the BLE beacon periodically broadcasts, and transmits traffic light ID to the server to request location information related to the traffic light. The server responds to the smart app with location information related to traffic lights by querying the DB. Smart apps can also use RSSI to calculate the distance to a traffic light. The smart app uses these distance information and traffic light-related location information to provide sound-type traffic light guidance to the handicapped such as visually impaired people. In addition, the proposed system transmits walking signal request information by establishing a connection with a BLE beacon using the GATT service to perform the function of a pedestrian operation signals.