基于NRF51822的可穿戴心率监测及防丢系统设计

发布时间：2019-03-22 06:04

【摘要】：近年来,随着智能可穿戴技术的快速发展和日益完善,越来越多的智能可穿戴产品出现在我们的生活中。而且这些智能可穿戴产品涉及的领域也从最开始的娱乐信息领域拓展到了运动生活和医疗保健等领域。智能可穿戴产品的出现,使人们的生活变得日益智能化。基于智能可穿戴技术的背景,结合近几年常有儿童被遗忘在汽车里而发生危险的现实情况,本文将设计一款专门用于预防此类事故发生的儿童可穿戴心率监测及防丢系统。这款系统与市面上已经出现的其他儿童防丢系统的不同之处在于,市面上的儿童防丢产品大都仅仅是基于防止儿童丢失的目的设计的。一些简易的防丢器只是通过距离设置来实现简单的防丢功能,这种防丢产品一般精确度不高。而一些高端的儿童防丢产品则加入了GPS定位、GSM位置查询和GPRS通信等技术来对儿童的位置信息进行追踪。这类产品虽然功能强大,但费用较高而且对于预防儿童被遗忘在汽车里而发生危险这类事件来说有点大材小用。所以本文针对上述问题设计了这款基于NRF51822可穿戴的心率监测及防丢系统。本系统的创新之处在于,除了具有丢失提醒的功能外还添加了心率监测功能,只要在通信连接范围内,在孩子被锁在车里的情况下,家长也可以通过心率监测来查看孩子的状态,避免意外的发生。本系统的设计将对预防儿童被遗忘在车里而发生危险这类事故的发生具有重要意义。本系统的设计是基于一款蓝牙4.0BLE芯片NRF51822,结合心率传感器,心率算法及RSSI测距技术,利用BLE无线通信技术与安卓智能手机进行通信的一款可穿戴心率监测及防丢系统。该系统整体上分为了两个个部分,一部分是穿戴在儿童身上的智能可穿戴产品,本文定义为从机,这也是本文将重点研究的部分。二是家长随身携带的智能安卓手机,本文定义为主机。其中,从机和主机之间的通信方式,本文将采用蓝牙4.0BLE技术完成主从机的数据交互。该系统预期实现的整体功能为,当从机与主机通过BLE技术连接时,主机即可对从机的佩戴者进行心率监测,当佩戴者的心率超出主机中的预设心率范围时,主机就会报警进行提示,从而达到对儿童的心率监测的目的。防丢功能则是基于RSSI测距原理的基础上实现的,当从机与主机的距离超出主机的预设距离范围时,主机会发出报警信号来提醒主机携带者,从机已丢失,从而达到防遗忘的目的。从机和主机之间的通信方式是本系统设计的重要环节之一,所以本文将在第2章对蓝牙4.0BLE技术进行详细介绍,包括蓝牙的发展历程,蓝牙4.0BLE的技术特点、协议栈特点及网络拓扑结构的特点。除此之外,作为系统的两个重要功能模块,即心率监测模块和防丢模块。本文也将在第二章对它们所涉及的技术进行介绍,如:心率监测模块用到的心率采集技术和防丢模块涉及到的测距技术。在对从机的硬件设计上,本文将采用模块化设计,即把从机在硬件结构上细分成各个模块进行设计。从机从总体上包括三大模块,即控制器模块、心率采集模块和电源模块。其中对控制器模块的设计,是基于主控芯片NRF51822进行一系列的外围配置电路设计,如:时钟电路设计、复位电路设计天线匹配电路的设计。心率采集模块主要是通过传感器完成对心率信号的采集和处理。而在电源模块的设计上,本文不仅要对供电模块进行设计,还将增加充电模块和电池电量检测模块的硬件电路设计。本文对从机的软件设计主要是对主控芯片NRF51822进行程序设计。本文将从通信链路的建立,心率监测功能的实现,RSSI防丢功能的实现和电池电量检测功能的实现这四方面进行设计。在这部分中,也将对涉及到的心率算法和RSSI测距原理进行详细介绍。最后,本文将通过两种方法对系统功能进行测试。一是通过抓取蓝牙广播通道和数据通道的数据包,对数据进行分析来判断系统功能。二是通过对应的APP对系统进行功能验证。
[Abstract]:In recent years, with the rapid development and perfection of the intelligent wearable technology, more and more intelligent wearable products appear in our lives. And the field of the intelligent wearable products also extends from the most starting entertainment information field to the fields of sports and health care and the like. The appearance of intelligent wearable products makes people's life more intelligent. Based on the background of the intelligent wearable technology, and in combination with the reality that children have been forgotten in the car in recent years, this paper will design a wearable heart rate monitoring and anti-loss system for children with such accidents. The system differs from other children's anti-loss systems already in the market in that most of the child-proof products on the market are designed based on the purpose of preventing the loss of children. Some simple anti-drop devices are only designed to achieve a simple anti-loss function by distance setting, which is generally not high in precision. And some high-end child anti-dropping products are added with GPS positioning, GSM position inquiry and GPRS communication technology to track the position information of the children. This kind of product, though powerful, has a high cost and is a little small for preventing children from being forgotten in the car. Therefore, this paper designs a wearable heart rate monitoring and anti-loss system based on NRF51822 for the above-mentioned problems. The innovation of the system is that the heart rate monitoring function is added in addition to the function with the missing reminding, so long as the parent can see the state of the child through the heart rate monitoring in the condition that the child is locked in the car in the communication connection range, and the accident can be avoided. The design of the system will be of great significance to the occurrence of such accidents that prevent children from being left in the car. The design of the system is based on a Bluetooth 4.0 BLE chip NRF51822, combined with a heart rate sensor, a heart rate algorithm and an RSSI ranging technology, and a wearable heart rate monitoring and anti-loss system for communicating with the Android smart phone by using the BLE wireless communication technology. The system is divided into two parts, and one part is an intelligent wearable product worn on a child. This article is defined as a slave, which is part of the research. The second is the intelligent Android mobile phone carried by the parents, which is defined as the host. In this paper, the communication mode between the slave and the host is completed, and the data interaction of the master-slave machine will be completed with the Bluetooth 4.0 BLE technique. The overall function of the system is that when the slave and the host are connected through the BLE technology, the host can monitor the heart rate of the wearer of the slave machine, and when the heart rate of the wearer exceeds the preset heart rate range in the host, the host can alarm to prompt, So as to achieve the purpose of monitoring the heart rate of the child. The anti-loss function is realized on the basis of the principle of RSSI ranging, and when the distance between the slave and the host exceeds the preset distance range of the host, the main opportunity issues an alarm signal to remind the host carrier that the slave is lost, thereby achieving the purpose of preventing forgetting. The communication mode between the slave and the host is one of the important links in the design of the system, so this paper will introduce the Bluetooth 4.0 technology in Chapter 2, including the development of Bluetooth, the technical features of Bluetooth 4.0 BLE, the characteristics of the protocol stack and the network topology. In addition, as two important functional modules of the system, the heart rate monitoring module and the anti-dropping module. The techniques involved in the second chapter are also described in the second chapter, such as the heart rate acquisition technique used by the heart rate monitoring module and the ranging technology involved in the anti-drop module. In the hardware design of the slave, this paper will adopt the modular design, that is, the slave machine is subdivided into various modules in the hardware structure. The slave system consists of three modules, namely, the controller module, the heart rate acquisition module and the power module. The design of the controller module is based on the design of a series of peripheral configuration circuit designs based on the main control chip NRF51822, such as a clock circuit design, a reset circuit design antenna matching circuit and the like. The heart rate acquisition module is mainly used for acquiring and processing the heart rate signal through the sensor. In the design of the power module, this paper not only designs the power supply module, but also increases the hardware circuit design of the charging module and the battery power detection module. The software design of the slave is mainly to program the main control chip NRF51822. This paper will be designed based on the establishment of the communication link, the realization of the heart rate monitoring function, the realization of the RSSI anti-dropping function and the realization of the battery power detection function. In this section, the heart rate algorithm and the RSSI ranging principle involved will also be described in detail. Finally, the system functions are tested by two methods. Firstly, the data packet of the Bluetooth broadcast channel and the data channel is grabbed, and the data is analyzed to judge the system function. The second is to perform functional verification on the system by the corresponding APP.
【学位授予单位】：成都理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TP368.33;TN925

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