前言

????????之前发布了一篇esp32采集数据发布到阿里云IOT平台的教程，有些同学觉得太复杂，那么接下来教大家一种更加简单的方法替代阿里云IOT让下位机和上位机进行数据交互。

一、本地搭建mqtt服务器（超简单）

网址链接：免费下载、试用 EMQ 产品

1.进入emqx官网，找到emqx开源版服务下载，选择你要安装的系统及版本，下载就行。

?2.启动mqtt服务。? ?windows版的启动命令：? ./bin/emqx start

3.然后打开浏览器进入 http://127.0.0.1:18083?Mqtt服务端管理后台。初始账号密码都是admin,在这里可以查看到有哪些用户接入订阅什么主题等信息。

?4.然后这就替代阿里云的IOT平台了，下位机esp32及上位机客户端都连接这个mqtt服务器进行数据传输。看下架构：

二、Esp32采集数据，转发到mqtt服务的具体实现（简单）

1.采集传感器数据上发

代码如下（示例）：

from umqtt.simple import MQTTClient
from machine import ADC, Pin
import network
import time
import machine
import dht
import json
from machine import Timer
#wifi账号密码
SSID="dmx"
PASSWORD="dmx123456"
#mqtt服务器域名
SERVER ='8.134.117.41'  #本地的填 127.0.0.1
#mqtt连接信息
CLIENT_ID = "1840707149"   #连接id要唯一，不然会相互挤下线
username='dmx123'
password='dmx111'
publish_TOPIC = 'dmx/1840707149' #发布信息主题（上传数据）
subscribe_TOPIC ='dmx/sub123'  #订阅主题（接收上位机的命令）
client=None
mydht=mylight=adc=rain=beep=led=None
beepmsg = []
def sub_cb(topic, msg):
    print(json.loads(msg))
    #print(json.loads(msg)['Led'])
    if 'Led' in json.loads(msg):
       if json.loads(msg)['Led'] == 1:
         led.value(1)
       if json.loads(msg)['Led'] == 0:
         led.value(0)
    if 'Beep' in json.loads(msg):
       if json.loads(msg)['Beep'] == 1:
         beep.value(1)
       if json.loads(msg)['Beep'] == 0:
         beep.value(0)
    if 'L298N' in json.loads(msg):
       if json.loads(msg)['L298N'] == 1:
         IN2.value(1)
         time.sleep(0.8)
         IN2.value(0)
       if json.loads(msg)['L298N'] == 0:
         IN2.value(1)
         time.sleep(0.8)
         IN2.value(0)

    
def ConnectWifi(ssid,passwd):   #连接wifi
    global wlan
    wlan=network.WLAN(network.STA_IF)         #create a wlan object
    wlan.active(True)                         #Activate the network interface
    #wlan.disconnect()                         #Disconnect the last connected WiFi
    wlan.connect(ssid,passwd)                 #connect wifi
    while not wlan.isconnected():
      pass
    print(wlan.ifconfig())
 
def apptimerevent(mytimer):
    try:
        wsData=ReadTemHum()
        Light=ReadLight()
        Led=led.value()
        Beep=beep.value()
        #rain = Pin(23,Pin.IN)
        print(ReadRain())
        Rain=ReadRain()
       
        #mymessage='{"data": {"name":%d,"temp": %d ,"hum": %d ,"light": %d,"led":%d,"beep":%d}, "method": "thing.event.property.post"}'%(1,wsData[0],wsData[1],Light,Led,Beep)
        mymessage = {"data":{"name":1,"hum":wsData[1],"temp":wsData[0],"light":Light,"led":Led,"beep":Beep,"rain":Rain,"beep_msg":beepmsg,"L298N":0}}
        client.publish(topic=publish_TOPIC,msg = json.dumps(mymessage), retain=False, qos=0)

    except Exception as ex_results2:
        print('exception',ex_results2)
        mytimer.deinit()
        
def ReadTemHum():   #获取温湿度
    mydht.measure()
    tem=mydht.temperature()
    hum=mydht.humidity()
    data=[tem,hum]
    print(data)
    return data
    
def ReadLight():
   adcData=mylight.read()
   Lightvalu=10240000/(adcData*1.1)-2500 #adc转换
   Light=round(Lightvalu)  #取整
   print(Light)
   return Light
   
def ReadRain():
  adc.atten(ADC.ATTN_11DB)      #设置衰减比
  adc.width(ADC.WIDTH_12BIT)    #设置12位数据宽度
  adcwww=adc.read()
  #adcwww = ((3.3-adcwww*(3.3/4095))*100/3.3)
  return(adcwww)
    
if __name__=='__main__':
    try:
        mydht=dht.DHT11(machine.Pin(4)) 
        mylight=ADC(machine.Pin(34))
        adc = ADC(Pin(35))  #设置IO35为模拟IO口
        led = Pin(19, Pin.OUT, value=0)
        EN = Pin(22,Pin.OUT,value = 1)  #EN
        IN1 = Pin(12,Pin.OUT, value=0)  #IN1
        IN2 = Pin(14,Pin.OUT,value=0)   #IN2
        beep=Pin(5,Pin.OUT,value=0)
        rain = Pin(23, Pin.IN)
        ConnectWifi(SSID,PASSWORD)
        client = MQTTClient(CLIENT_ID, SERVER,0,username,password,60)     #create a mqtt client
        #print(client)
        client.set_callback(sub_cb)                         #set callback
        client.connect()                                    #connect mqtt
        client.subscribe(subscribe_TOPIC)                   #client subscribes to a topic
        mytimer=Timer(0)
        mytimer.init(mode=Timer.PERIODIC, period=3000,callback=apptimerevent)   #初始化回调函数
        while True:
          client.wait_msg()                              #wait message          
    except Exception  as ex_results:
        print('exception1',ex_results)
    finally:
      if(client is not None):
        client.disconnect()
      #wlan.disconnect()
      #wlan.active(False)