Design and implementation of a fall monitor system by using a 3-axis accelerometer in a smart phone

In this paper we use the accelerometer of a smart phone to design and implement a fall monitor with mobility detection function for the user. We not only analyze the change of acceleration but also analyze the four typical actions of humans. These are going upstairs, going downstairs, standing up, sitting down, running and jumping. Then we compare the four actions with the characteristics of a fall. These are weightlessness, impact, immobility and overturning of the body. Because the waist is the center of gravity in the human body, our system is used more effectively when we place the smart phone at the waist. Our system is based on an open source system platform and the accelerometer in the smart phone.