| dc.description.abstract | Since the 1950s, the small and medium-sized construction industry in Taiwan has gradually declined, the tall buildings have been uprooted from the flat ground, but labor safety has been ignored in the construction. The biggest reason is that the labor safety equipment is considered as an invisible cost by the management. If there are no casualties, it will be regarded as a waste; therefore, the construction industry often ignores it. If it can effectively reduce the cost of purchase, maintenance, and operation difficulties, besides, it is easier for people to carry, it can significantly enhance the willingness of the construction industry to purchase labor safety facilities. However, it still exists many limitations in the existing research and corresponding devices for detecting falls. Therefore, this research develops a fall detection system based on an accelerometer. The system adopts the detection method based on a threshold composed of a small self-packaged sensor unit and Transmission Control Protocol (TCP). The sensor unit includes a three-axis accelerometers + gyroscope module (MPU 9250) and a development version (ESP8266). This study designed 15 groups of simulated situation experiments, including seven fall situations and eight daily activity situations, to evaluate the performance of the proposed system, which was installed on the subjects’ heads, waist, and feet, respectively. The results show that although the accelerometer′s discrimination tends to be accurate, it is easier for the head and feet to judge the movement of daily life as falling mistakenly, and higher accuracy can be obtained in the system installed at the waist. Based on the experiment results, the threshold of the accelerometer threshold is revised as 0.25g. In addition, this study uses Euler angles as the second threshold to reduce the false alarm. Conclusively, construction workers can easily carry this device to obtain the triaxial acceleration and Euler angles, calculate and transmit the data to the cloud-monitoring terminal, set the threshold according to the characteristic values of the historical database then identify falls. If a fall is detected and recognized, a signal will be sent to the mobile phone, which will give an alarm and automatically call the emergency contact for a timely rescue. Alternatively, it can send messages directly to the public works station through LORA low-power long-distance wireless mode to start rescue operations. | en_US |