Implementation and pilot testing of an Android-based real-time activity detection system

• Online Access: http://hdl.handle.net/2047/d20003208

Real-time measurement of physical activity type on mobile devices could advance physical activity measurement studies and create new opportunities for real-time health interventions that promote physical activity. In this work, an algorithm for four-class activity detection ("Ambulation", "Cycling", "Sedentary" and "Other") from wrist or ankle accelerometer-based activity monitors was extended to run in real-time on Android mobile phones with wireless accelerometers. Experiments validating the method using an existing activity dataset were replicated in the new Java-based system and results were verified to be consistent with the former MATLAB implementation by Mannini et al. The Android application was implemented with two modes: the continuous mode, which was suitable for instant classification (10s latency) and a power-efficient burst mode, which could be utilized in large scale study but with longer latency (up to 70s latency).