论文总字数：24848字

摘 要

近几年窄带物联网NB-IoT（Narrow Band Internet of Things）和长距离无线技术LoRa（Long Range Radio），发展在窄带通信技术中发展最为快速，这主要是因为它们长距离、低功耗的通信优势适用于物联网应用环境。而在烟雾报警方面，传统的无线报警方案zigbee在建筑应用场景存在效能低、信号穿透能力差、通信距离短等问题，相关公司组织急需更有优势的解决方案。本文根据这种情况对LoRa技术的特点及优势进行分析提出了基于LoRa技术的烟感节点设计。

本文旨在实现烟感节点烟度数据采集和节点和网关信号通信功能。通过查询LoRa技术相关文献了解LoRa节点数据收发方式及相关参数，配合对相关低功耗微控制单元MCU（Microcontroller Unit）进行学习，对LoRa模块射频RF（Radio Frequency）部分和低功耗控制方面进行软件设计，最后针对烟感节点在烟雾报警方面需求，对烟雾探测模块进行了硬件设计，追加蜂鸣器报警功能。

本文设计烟感节点能依据设计自动进入低功耗模式并且正常唤醒，烟雾探测模块能判断烟度是否超出阈值并进行蜂鸣报警和联网报警，但是在信号收发方面仍有问题未解决。在低功耗唤醒方面活跃停机实际测试与设定时间延迟0.5s，不影响烟感节点正常工作。

关键词：LoRa，低功耗，烟感节点

Abstract

In recent years, NB-IoT and LoRa have developed fastest in narrowband communication technology, mainly because of their communication advantages,which apply to the IoT application environment,such as long distance and low power consumption. In terms of smoke alarms, the traditional wireless alarm scheme zigbee has some problems in such as low performance, poor signal penetration capability, and short communication distance in the architectural application scenario. Relevant company and organizations need more advantageous solutions urgently. Based on the analysis of the characteristics and advantages of LoRa technology, this paper proposes a smoke-sensing node design ,which based on LoRa technology.

This paper aims to achieve two functions, one is to collect smoke data, the other is the communication between nodes and gateway. By querying LoRa technology related literature, studying the methods about data transmission, data reception and related parameters configuration. learning how to control MCU, and designed the software for the RF part of the LoRa module and low power control in MCU. Finally, satisfied the need for smoke detectors in smoke alarms function, design the hardware for the smoke detection module, and added to buzzer alarm function.

The smoke-sensing node here can automatically enters low power mode and wakes up normally. The smoke detection module can judge whether the smoke exceeds the threshold, then perform buzzer alarm and network alarm. However, there are still problems in transmission and reception. Maybe, the listening function is misconfigured. In actual test, MCU wake-up time was delayed about 0.5sec, which did not affect the smoke node to work properly.

KEY WORDS:LoRa,Low power consumption,smoke-sensing nodes

目 录

摘要 I

Abstract II

第一章 绪论 1

1.1 背景和意义 1

1.2 国内外研究现状 2

1.2.1 国外研究现状 2

1.2.2 国内研究现状 4

1.3 本文主要内容 5

第二章 LoRa烟感节点系统框架设计 7

2.1 LoRa概述 7

2.1.1 LoRa技术特点及优势 7

2.1.2 LoRa应用 9

2.1.3 无线报警系统的发展及趋势 10

2.2 烟雾传感器的分类及特点 11

2.3 LoRa烟感节点总体设计方案 13

2.3.1 烟感节点的需求分析 13

2.3.2 烟感节点的总体设计 13

2.4 本章小结 14

第三章 硬件设计 15

3.1 烟感节点的设计要求 15

3.2 硬件设计框图 15

3.3 烟感节点各模块设计 16

3.3.1 LoRa模块硬件原理图 16

3.3.2 处理模块硬件原理图 18

3.3.3 处理模块PCB设计 18

3.3.4 烟雾探测模块硬件原理图 19

3.3.5 烟雾探测模块PCB设计 21

3.4 本章小结 22

第四章 系统软件设计 23

4.1 烟感节点软件流程图 23

4.2 处理模块软件设计 23

4.3 LoRa模块软件设计 24

4.4 本章小结 25

第五章 软硬件测试 26

5.1 处理模块软件低功耗模式唤醒测试 26

5.2 LoRa模块低功耗唤醒测试 26

5.3 LoRa模块信号收发测试 26

5.4 本章小结 27

第六章 结论和展望 28

6.1 结论 28

6.2 展望 28

参考文献 30

致谢 31

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