Design Of Low Power Non-button Sport Watch

With the emergence of wearable devices and the increasing focus on health care, sports watch as one kind of wearable device is gradually entering our life. Compared with the sports watch with buttons, a non-button sports watch has more fashional looks and better waterproof. Moreover, it provides a good user experience and step-counting performance. However, it faces the problem of power consumption. This paper takes the advantage of non-button sports watch and tackles its power issues. The main research and innovation of this paper include:Firstly, this paper defines a non-button sports watch system, including the function definitions and working modes. After that, every function module of the system is designed, including the low power optimization algorithm in both of the tapping detection and motion detection modules. Finally, these function modules are integrated and this low power non-button sports watch is realized.The non-button sports watch designed in this paper uses tapping to control the display of time and working modes, and the change of motion modes instead of buttons. Based on the existing tapping algorithms, this paper proposes a prediction tapping detection algorithm, which adds pre-arm-raising detection for optimizition. Without degrading the user experience, this optimization algorithm can greatly reduce the computing complexity and time in order to reduce power consumption. In addition, this paper also proposes the self-adaption pedometer algorithm which will dynamically adjust the acceleration sensor sampling rate and the times of pedometer calculation according the motion modes. This self-adaption pedometer algorithm can reduce power consumption effectively without reducing the pedometer precision. Moreover, a sleeping-turn-over-time detection module is added to detect people’s sleeping quality.This paper also designs a complete communication module based on Bluetooth Low Energy (BLE) technology. This communication module can effectively realize the data and time synchromization between the sports watch and a mobile phone. The motion and sleeping database is presented as well. This database defines the motion and sleeping data structure, the database initialization process, the data opration mechanism such as reading, writing and erasing, and considers the overflow problem etc. It can manage the motion and sleeping data effectively.This paper designs a low power non-button sports watch based on TI SoC CC2541and ADI acceleration sensor ADXL362. The prediction tapping detection algorithm and self-adaption pedometer algorithm are applied into the sports watch to optimize power consumption. Experimental results have shown that the proposed algorithms can shorten MCU execution time effectively and reduce system power consumption significantly considering user experience and pedometer precision. In addition, the design of the communication module based on Bluetooth Low Energy technology and the motion&sleeping database has great significance to other similar products.