Abstract
Recently, traffic safety is an important issue for the governments around the world that also investigate how to minimize the risk of traffic accident. According to NTHSA research, the majority of car crash is rear-end collision. This study provides a system to detect emergency braking and warns the rear vehicle at the same time. This study emphasizes on the circuit system design which includes a comparator, a signal generator, and a LED driver. The designed circuit has been fabricated by TSMC 1P4M 0.35μm CMOS standard process. The emergency signal from g-sensor is detected by comparator. Using signal generator to create a 5Hz oscillation makes LED flash at 5Hz. Finally, LED driver not only driving LED but also providing a high current which lets LED have high brightness to warn rear vehicle.