Overview / Usage

Human Activity Recognition which use sensors to recognize human actions, have been studied for a long time to produce a simpler system with higher precision. However, there are a very limited number of projects that investigate a human activity recognition system built right on the smartphone. A great advantage of this integrated system is the real time and full time supervision. The human activities recognition built right in a smart phone promises to open up a new direction not only in monitoring and health care but also in other fields.
Smartphones are going to get more popular in the world over the next five years. According to Ericsson's mobility report, there will be a massive jump from the 2.6 billion smartphone users recorded in 2014 to 6.1 billion by 2020. These smartphones are also equipped with a lot of sensors.
In detail, accelerometer sensor measures acceleration in three orthogonal axes. All of objects in the Earth are affected by the gravity. The linear acceleration measures the acceleration effect of the device movement, excluding the effect of Earth's gravity on the device. The gyroscope uses Earth’s gravity to help determine orientation of smartphone.
Thus, the idea of utilization of these sensors to make a smartphone application for human activities recognition became more realistic.
Android is the most popular mobile OS in the world with more than 82% phones running on it and with Google’s continuously improving features by listening to feedback from its users, it is only going to get more popular. In Android, Google has introduced a set of APIs (Application Programming Interface), which allow the developer to connect Google services to their Android phone for receiving the human activity recognition results. Google API can recognize six type of activities which include “in vehicle”, “on bicycle”, “on foot”, “running”, “still” and “walking”. However, this system required the connection to Google server inorder-to send the requests and receive the results.