ESP32 MQTT服务通信传输DHT11温湿度数据及控制LED

关于如何在Windows下设置mqtt服务器请移步上一篇博文：python MQTT服务通信

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20210629更
python客户端使用pyqtgraph+pyqt5的方式进行绘图，将mqtt数据接收处理部分放到一个qthread上去，每次接收到数据后处理，然后通过信号的方式发送到主线程，主线程绑定一个槽函数，进行绘图的更新操作（代码见文末）

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1.环境准备

1. mosqutto服务端程序，需要进行一些配置，重启服务，默认服务端口为1883
2. mqttx客户端程序，方便订阅和发布信息：https://github.com/emqx/MQTTX/releases
3. Arduino通过包管理器安装PubSubClient
4. esp32连接的网络和运行mosqutto服务程序的电脑处在同一个网段

2.arduino代码

/*********
  @author: Wenqing Zhou ([email protected])
  @github: https://github.com/ouening
  
  功能
  ESP32搭建一个MQTT客户端，订阅主题"esp32/output"，以此控制led灯；发布主题
  "esp32/dht11/temperature"和"esp32/dht11/humidity"将DHT11获取的温湿度数据推给
  MQTT服务器，如果其他客户端在相同的MQTT服务器下订阅了该主题，便可获取对应的温度或者湿度
  数据。
  
  参考链接：Complete project details at https://randomnerdtutorials.com  
*********/
#include 
#include 
#include 
#include 
#include 
#include 
#include 

// Replace the next variables with your SSID/Password combination
const char* ssid = "wifi名称";
const char* password = "wifi密码";

// Add your MQTT Broker IP address, example:
const char* mqtt_server = "192.168.28.87"; //先测试本机mqtt服务，该地址在windows下通过ipconfig查看，要和esp32连接在同一个网络
//const char* mqtt_server = "YOUR_MQTT_BROKER_IP_ADDRESS";
const char *id = "ESP32";
const char *user = "kindy";
const char *pass = "123456";

WiFiClient espClient;
PubSubClient client(espClient); // MQTT服务设置了非账号密码不能使用，所有在connect的时候要设置账号密码
long lastMsg = 0;
char msg[50];
int value = 0;

/* 设置DHT11 */
#define DHTPIN 4     // Digital pin connected to the DHT sensor 
#define DHTTYPE    DHT11     // DHT 11
DHT_Unified dht(DHTPIN, DHTTYPE);

float temperature = 0;
float humidity = 0;
// LED Pin
const int ledPin = 2;

void setup() {
     
  Serial.begin(115200);
  pinMode(ledPin, OUTPUT);
  // default settings
  setup_wifi();
  client.setServer(mqtt_server, 1883);
  client.setCallback(callback); // 绑定回调函数
}

void setup_wifi() {
     
  delay(10);
  // We start by connecting to a WiFi network
  Serial.println();
  Serial.print("Connecting to ");
  Serial.println(ssid);
  WiFi.mode(WIFI_STA); // station mode
  WiFi.begin(ssid, password);

  while (WiFi.status() != WL_CONNECTED) {
     
    delay(1000);
    Serial.print(".");
  }

  Serial.println("");
  Serial.println("WiFi connected");
  Serial.println("IP address: ");
  Serial.println(WiFi.localIP());

    /* ====== 初始化DHT11 ========*/
  dht.begin();
  Serial.println(F("DHTxx Unified Sensor Example"));
  // Print temperature sensor details.
  sensor_t sensor;
  dht.temperature().getSensor(&sensor);
  Serial.println(F("------------------------------------"));
  Serial.println(F("Temperature Sensor"));
  Serial.print  (F("Sensor Type: ")); Serial.println(sensor.name);
  Serial.print  (F("Driver Ver:  ")); Serial.println(sensor.version);
  Serial.print  (F("Unique ID:   ")); Serial.println(sensor.sensor_id);
  Serial.print  (F("Max Value:   ")); Serial.print(sensor.max_value); Serial.println(F("°C"));
  Serial.print  (F("Min Value:   ")); Serial.print(sensor.min_value); Serial.println(F("°C"));
  Serial.print  (F("Resolution:  ")); Serial.print(sensor.resolution); Serial.println(F("°C"));
  Serial.println(F("------------------------------------"));
  // Print humidity sensor details.
  dht.humidity().getSensor(&sensor);
  Serial.println(F("Humidity Sensor"));
  Serial.print  (F("Sensor Type: ")); Serial.println(sensor.name);
  Serial.print  (F("Driver Ver:  ")); Serial.println(sensor.version);
  Serial.print  (F("Unique ID:   ")); Serial.println(sensor.sensor_id);
  Serial.print  (F("Max Value:   ")); Serial.print(sensor.max_value); Serial.println(F("%"));
  Serial.print  (F("Min Value:   ")); Serial.print(sensor.min_value); Serial.println(F("%"));
  Serial.print  (F("Resolution:  ")); Serial.print(sensor.resolution); Serial.println(F("%"));
  Serial.println(F("------------------------------------"));
}

void callback(char* topic, byte* message, unsigned int length) {
     
  Serial.print("Message arrived on topic: ");
  Serial.print(topic);
  Serial.print(". Message: ");
  String messageTemp;
  
  for (int i = 0; i < length; i++) {
     
    Serial.print((char)message[i]);
    messageTemp += (char)message[i];
  }
  Serial.println();

  // Feel free to add more if statements to control more GPIOs with MQTT

  // If a message is received on the topic esp32/output, you check if the message is either "on" or "off". 
  // Changes the output state according to the message
  if (String(topic) == "esp32/output") {
     
    Serial.print("Changing output to ");
    if(messageTemp == "on"){
     
      Serial.println("on");
      digitalWrite(ledPin, HIGH);
    }
    else if(messageTemp == "off"){
     
      Serial.println("off");
      digitalWrite(ledPin, LOW);
    }
  }
}

/* 重连mqtt服务器 */
void reconnect() {
     
  // Loop until we're reconnected
  while (!client.connected()) {
     
    Serial.print("Attempting MQTT connection...");
    //MQTT服务设置了非账号密码不能使用，所有在connect的时候要设置账号密码
    if (client.connect(id, user, pass)) {
      
      Serial.println("connected");
      // 订阅mqtt主题
      client.subscribe("esp32/output");
    } else {
     
      Serial.print("failed, rc=");
      Serial.print(client.state());
      Serial.println(" try again in 5 seconds");
      // Wait 5 seconds before retrying
      delay(5000);
    }
  }
}
void loop() {
     
  if (!client.connected()) {
     
    reconnect();
  }
  client.loop();

  long now = millis();
  if (now - lastMsg > 5000) {
     
    lastMsg = now;
    char tempString[8];
    // Convert the value to a char array
    char humString[8];

    // 获取温度数据
    sensors_event_t event;
    dht.temperature().getEvent(&event);
    if (isnan(event.temperature)) {
     
      Serial.println(F("Error reading temperature!"));
    }
    else {
     
      dtostrf((float)event.temperature,2,2,tempString); // convert to String
      Serial.print("Temperature: ");
      Serial.println(tempString);
      client.publish("esp32/dht11/temperature", tempString); // 发布信息，第一个参数是主题
    }
    // Get humidity event and print its value.
    dht.humidity().getEvent(&event);
    if (isnan(event.relative_humidity)) {
     
      Serial.println(F("Error reading humidity!"));
    }
    else {
     
      dtostrf((float)event.relative_humidity,2,2,humString);
      Serial.print("Humidity: ");
      Serial.println(humString);
      client.publish("esp32/dht11/humidity", humString);
    }
  }
}

3.python mqtt客户端数据可视化

借助包paho-mqtt，可以在用python创建mqtt客户端，订阅相关主题，并用matplotlib可视化，代码如下：

# -*- coding: utf-8 -*-
"""
Created on Sun Jun 20 11:28:12 2021

@author: Wenqing Zhou ([email protected])
@github: https://github.com/ouening
"""

# 参考链接：
# （1）https://www.cnblogs.com/chenpingzhao/p/11383856.html
# （2）https://www.emqx.cn/blog/how-to-use-mqtt-in-python

# 除了以下通过python程序接收mqtt订阅信息外，还可以下载相关的mqtt客户端程序，例如https://mqttx.app/zh
import random
from paho.mqtt import client as mqtt_client
import matplotlib.pyplot as plt
import datetime

plt.rcParams.update({
     
    "font.family": "serif",
    "font.serif": ["Times New Roman"], #Times New Roman
    "font.size":11,
    "legend.fancybox": False,
    "legend.frameon": True,
    "legend.framealpha": 1.0,
    "legend.shadow": False,
    "legend.facecolor": 'white',
    "legend.edgecolor": 'none',  # 'none', 0.8
    "legend.fontsize": "small",  # {'xx-small', 'x-small', 'small', 'medium', 'large', 'x-large', 'xx-large'}
    "text.usetex": False,
    })

# broker = 'broker.emqx.io'
# broker = "192.168.28.87"
broker = '公网服务器ip地址'
port = 1883
username = 'kindy'
passwd = 'kindy'
# topic = "mytopic/test" # esp32程序设定的推送主题
topic1 = "esp32/dht11/humidity"
topic2 = "esp32/dht11/temperature"
# generate client ID with pub prefix randomly
client_id = f'esp32'

count = 0
x1, x2 = [], []
# 存储数据
sub_dict = {
     topic1:[], topic2:[]}

def connect_mqtt() -> mqtt_client:
    def on_connect(client, userdata, flags, rc):
        if rc == 0:
            print("Connected to MQTT Broker!")
        else:
            print("Failed to connect, return code %d\n", rc)

    client = mqtt_client.Client(client_id)
    client.on_connect = on_connect

    # 连接mqtt服务器
    client.username_pw_set(username, password=passwd)
    client.connect(broker, port)
    return client

def on_message(client, userdata, msg):
    # 存储数据
    global count
    print(f"Received `{msg.payload.decode()}` from `{msg.topic}` topic")
    # 绘图
    plt.ion()
    count = count + 1

    if msg.topic==topic1:
        sub_dict[msg.topic].append(float(msg.payload.decode()))
        x1.append(datetime.datetime.now()) # add timestamp
    if msg.topic==topic2:
        sub_dict[msg.topic].append(float(msg.payload.decode()))
        x2.append(datetime.datetime.now()) # add timestamp
    # 只存储100个数据
    if (len(x1)==100) and (len(sub_dict[topic1])==100):
        x1.pop(0)
        sub_dict[topic1].pop(0)
    if (len(x2)==100) and (len(sub_dict[topic2])==100):
        x2.pop(0)
        sub_dict[topic2].pop(0)
    # y_hum.append(sub_dict[topic1]) # add temperature
    # print('Temp,Vbat,A0,count',d,count)
    plt.clf()

    plt.plot(x1, sub_dict[topic1], label=topic1)
    plt.plot(x2, sub_dict[topic2], label=topic2)
    plt.gcf().autofmt_xdate()
    plt.xlabel('time')
    plt.ylabel('Temperature')
    plt.legend(loc='best')
    plt.grid('on')
    plt.show()
    plt.pause(0.01)

def subscribe(client: mqtt_client):
    client.subscribe(topic1)
    client.subscribe(topic2)
    client.on_message = on_message


def run():
    client = connect_mqtt()
    subscribe(client)
    client.loop_forever()


if __name__ == '__main__':
    run()

效果如下：

4.MQTTX客户端

MQTTX设置连接：

MQTTX订阅主题：

MQTTX发布信息：

本例子是用在本地电脑测试的 ，如果运行mosqutto服务程序的是在远端的服务器，或者其他厂商提供的物联网服务器，相关设置应该都大同小异，主要是***ip地址、端口，账号密码***等；另外，从mqtt可选的发送和接收数据类型来看，除了普通的文本数据（plaintext）外，还可以发送json等高级数据格式。

已知问题：python构建mqtt客户端再用matplotlib可视化的程序会一直阻塞，对图形不好控制，下一步应该考虑多进程，将绘图功能放到其他子线程，不要干扰主线程；另外可以采用pyqt5或者pyside进行界面封装。

# -*- coding: utf-8 -*-
"""
Created on Tue Jun 29 14:27:51 2021

@author: Wenqing Zhou ([email protected])
@github: https://github.com/ouening
"""

import sys
import ctypes
import time
import pyqtgraph as pg
import threading
import serial
from collections import deque
from PyQt5.QtCore import *
from PyQt5.QtGui import *
from PyQt5.QtWidgets import *
import datetime
from matplotlib.backends.backend_qt5agg import FigureCanvasQTAgg as FigureCanvas
import matplotlib.pyplot as plt
from pyqtgraph import DateAxisItem
from paho.mqtt import client as mqtt_client

__version__ = '1.0'

broker = 'xx.xx.xx.xx'
port = 1883
username = 'kindy'
passwd = 'xxxx'
# topic = "mytopic/test" # esp32程序设定的推送主题
topic1 = "esp32/dht11/temperature"
topic2 = "esp32/dht11/humidity"
# generate client ID with pub prefix randomly
client_id = f'esp32'


class MQTTWorker(QThread):
    data_signal = pyqtSignal(object)
    def __init__(self):
        super().__init__()
        # 初始化mqtt
        self.count = 0
        self.history = 7200
        self.sub_dict = {
     'x1':[], topic1:[], 'x2':[], topic2:[]}
        def on_connect(client, userdata, flags, rc):
            if rc == 0:
                print("Connected to MQTT Broker!")
            else:
                print("Failed to connect, return code %d\n", rc)
    
        self.client = mqtt_client.Client(client_id)
        self.client.on_connect = on_connect
    
        # 连接mqtt服务器
        self.client.username_pw_set(username, password=passwd)
        self.client.connect(broker, port)

        # 订阅主题
        self.client.subscribe(topic1)
        self.client.subscribe(topic2)

        # 信息接收回调函数
        def on_message(client, userdata, msg):
            # 存储数据
            print(f"Received `{msg.payload.decode()}` from `{msg.topic}` topic")
            # 绘图
            self.count += 1
        
            if msg.topic==topic1:
                self.sub_dict[msg.topic].append(float(msg.payload.decode()))
                self.sub_dict['x1'].append(time.time()) # add timestamp
            if msg.topic==topic2:
                self.sub_dict[msg.topic].append(float(msg.payload.decode()))
                self.sub_dict['x2'].append(time.time()) # add timestamp
            # 只存储100个数据
            if (len(self.sub_dict['x1'])==self.history) and (len(self.sub_dict[topic1])==self.history):
                self.sub_dict['x1'].pop(0)
                self.sub_dict[topic1].pop(0)
            if (len(self.sub_dict['x2'])==self.history) and (len(self.sub_dict[topic2])==self.history):
                self.sub_dict['x2'].pop(0)
                self.sub_dict[topic2].pop(0)
    
            self.data_signal.emit(self.sub_dict) # 发送信号

        self.client.on_message = on_message

    # 停止qthread线程
    def stop(self):
        self.terminate()
        print("QThread terminated")

    # mqtt客户端循环接收数据
    def run(self):
        self.client.loop_forever()

class MainWindow(QMainWindow):
    newdata = pyqtSignal(object) # 创建信号
    def __init__(self, filename=None, parent=None):
        super(MainWindow, self).__init__(parent)
        self.setWindowTitle('温湿度数据采集')
        self.setWindowIcon(QIcon(r"D:\Github\bouncescope\smile.ico"))
        self.connected = False

        # 实例化线程
        self.mqtt_worker = MQTTWorker()

        # QTimer.singleShot(0, self.startThread)
        self.btn = QPushButton('点击运行！')
        self.label = QLabel("实时获取温湿度数据")
        self.label.setAlignment(Qt.AlignCenter)
        self.data_label = QLabel("Data") # label显示数据

        self.pw = pg.PlotWidget()
        self.pw_hum = pg.PlotWidget()
        # setup pyqtgraph
        self.init_pg_temp()  # 温度
        self.init_pg_hum()  # 湿度
        
        # 添加布局，注意布局的嵌套
        vb = QVBoxLayout()
        hb = QHBoxLayout()

        vb.addWidget(self.label)
        vb.addWidget(self.btn)

        hb.addWidget(self.pw)
        hb.addWidget(self.pw_hum)

        vb.addLayout(hb)
        vb.addWidget(self.data_label)
        # 添加一个widget，因为widget才有setLayout方法，MainWindow没有
        self.cwidget = QWidget()
        self.cwidget.setLayout(vb)
        self.setCentralWidget(self.cwidget)

        self.mqtt_worker.data_signal.connect(self.process_mqtt) # 连接处理，mqtt信号的槽函数
        self.btn.clicked.connect(self.startThread) # 启动mqtt线程

    def init_pg_temp(self):
        # 设置图表标题
        self.pw.setTitle("温度变化趋势",
                         color='008080',
                         size='12pt')
        # 设置上下左右的label
        self.pw.setLabel("left","气温(摄氏度)")
        self.pw.setLabel("bottom","时间")
        # 设置Y轴 刻度 范围
        # self.pw.setYRange(min=10, max=50)
        # 显示表格线
        self.pw.showGrid(x=True, y=True)
        # 背景色改为白色
        self.pw.setBackground('w')
        # 居中显示 PlotWidget
        # self.setCentralWidget(self.pw)
        axis = DateAxisItem()
        self.pw.setAxisItems({
     'bottom':axis})
        self.curve_temp = self.pw.getPlotItem().plot(
            pen=pg.mkPen('r', width=1)
        )
    def init_pg_hum(self):
        
        # 设置图表标题
        self.pw_hum.setTitle("湿度度变化趋势",
                         color='008080',
                         size='12pt')
        # 设置上下左右的label
        self.pw_hum.setLabel("left","湿度")
        self.pw_hum.setLabel("bottom","时间")
        # 设置Y轴 刻度 范围
        # self.pw_hum.setYRange(min=10, # 最小值
        #                   max=100)  # 最大值
        # 显示表格线
        self.pw_hum.showGrid(x=True, y=True)
        # 背景色改为白色
        self.pw_hum.setBackground('w')
        axis = DateAxisItem()
        self.pw_hum.setAxisItems({
     'bottom':axis})
        self.curve_hum = self.pw_hum.getPlotItem().plot(
            pen=pg.mkPen('b', width=1)
        )

    # 处理mqtt数据 sub_dict = {'x1':[], topic1:[], 'x2':[], topic2:[]}
    def process_mqtt(self, sub_dict):
        try:
            self.data_label.setText(str(datetime.datetime.now()))
            self.curve_temp.setData(sub_dict['x1'], sub_dict[topic1])
            self.curve_hum.setData(sub_dict['x2'], sub_dict[topic2])
        except:
            print(sub_dict)

    def startThread(self):
        print('Start lisnening to the mqtt')
        self.btn.setEnabled(False)
        self.mqtt_worker.start()
        
    def stopThread(self):
        self.mqtt_worker.stop()
        print ('Stop the thread...')

    def closeEvent(self, event):
        if self.okToContinue():
             event.accept()
             self.stopThread()
        else:
            event.ignore()

    def okToContinue(self):
        return True

if __name__ == '__main__':

    app = QApplication(sys.argv)
    win = MainWindow()

    win.show()
    app.exec_()

已知问题：mqtt服务器连接断开后，程序就无法继续获取数据绘图了，有待解决