A Step Detection Method And The Research Of Its Application On The Wrist-type Pedometer

In the21st century, obesity has becoming one of the most serious public health crisis thatfaced by humanity, and the consequent high blood pressure, high cholesterol, high bloodsugar, cardiovascular diseases and other complications are also turning to be an incrementalthreat to human health. Under this condition, improving physical fitness, enhancing individualimmunity and preventing the chronic diseases are showing increasingly importance. And thebest way to enhance immunity, certainly, is to take moderate physical exercise. Thenquantifying the exercise is the key factor. Pedometer as a portable testing equipment, couldquantify and monitor the daily movement of the users, which will provide a criterion for usersto refer and compare while that also will promote people to develop a reasonable training planand realize their goals of doing moderate exercise. With the development of science andtechnology in recent years, the emergence of various wrist products is triggering a newrevolution in the IT field. For people’ needs of quantifying the exercise and with thepromotion of the development of science and technology, designing a step detection methodand applying that to the wrist pedometer becomes very important and necessary.The study of this paper is divided into two parts: First, a human movement model isestablished and a step detection method that applies to the wrist is designed according to thecharacteristics of the detected waveform of the acceleration and the periodic changes of theacceleration that due to the movement of wrist and body. Secondly, the hardware structure ofthe pedometer is designed and the step detection method is applied to the wrist pedometer bymaking use of a three-axis acceleration sensor to collect data. The experimental result showsthat the wrist pedometer in this paper could detect the step number accurately.And the above experimental evaluation of the pedometer in this paper is operated as this:First, the pedometer designed in this paper is tested by several people in several differentmovement forms and the result shows that a95%accuracy is reached, which satisfies therequirement of a pedometer design; Secondly, a comparison is carried out between ourpedometer and other methods or products. The method for comparison is the dynamicthreshold detection method which is widely used by most of the pedometer software. Theproducts for comparison are the Codoonsport pedometer software, the Fuelband by Nikecompany and jWotch from TongJie company in JiaXing China. It is found that the overallperformance of the pedometer in this paper is better.The contribution of this paper is that a set of step detection method is designed andsuccessfully applied in the wrist pedometer. Compared with other types of pedometer, thedifficulty of designing a method for the wrist pedometer is how to effectively remove theinterference signal caused by the swing of wrist. As we all know, the position of the wrist and the way that it swing vary from person to person when body moves, and even for the sameperson that no one can move in the exactly same way twice. And no evidence has been shownthat the movement of wrist and body are related in some particular way. All these bring achallenge for the design of a step detection method used on the wrist, and because of that theproducts on the market and the study in the literature on this method are still relatively scarceand have obvious shortcomings. This paper gives a good solution to this problem.