一、介绍
本项目采用ESP32开发板，每X秒采集一次DTH11温湿度传感器数据，通过ESP32自带WIFI，经MQTT协议传送给ActiveMQ中间件，便于后续开发和使用。
二、材料介绍
ESP32 CP2102 带WIFI 22元
DTH11 4元
透明防水塑料壳 8元
MicroUSB电源线 5元
三、ActiveMQ服务器配置
我这里使用docker一键部署ActiveMQ，并将MQTT端口映射到1883端口
四、硬件安装
将DTH11的正负连接ESP32的3.3V和GND针脚，数据连接至D13针脚
五、代码开发
1、ESP32刷写为MPython开发环境
2、新建main.py，此脚本ESP32上电即会自动运行
main.py 主程序
importrandomfrommachineimportPin,SPIimporttime,machineimportdht11,network,mrequestsfromumqtt.simpleimportMQTTClientimportujsonMQTT_CLIENT_ID=f'python-mqtt-{random.randint(0,1000)}'MQTT_BROKER="10.0.10.129"MQTT_USER=""MQTT_PASSWORD=""MQTT_TOPIC="mqtt001"wlan=network.WLAN(network.STA_IF)wlan.active(True)dht=dht11.DHT11(Pin(13))print("Connecting to MQTT server... ",end="")client=MQTTClient(MQTT_CLIENT_ID,MQTT_BROKER,user=MQTT_USER,password=MQTT_PASSWORD)print("Connected!")whileTrue:ifwlan.isconnected()==False:print("connect WiFi")try:wlan.connect('WiFissid','wifipassword')except:print("wifi false")#passelse:dht.measure()try:client.connect()message=ujson.dumps({"temp":dht.temperature(),"humidity":dht.humidity(),})#print("Reporting to MQTT topic {}: {}".format(MQTT_TOPIC, message))client.publish(MQTT_TOPIC,message)print("mqtt push ok")client.disconnect()except:print("mqtt push not ok")#passtime.sleep(3)
dth11.py DTH11传感器支持库
# DHT11/DHT22 driver for MicroPython on ESP8266# MIT license; Copyright (c) 2016 Damien P. Georgetry:fromespimportdht_readintoexcept:frompybimportdht_readintoclassDHTBase:def__init__(self,pin):self.pin=pin self.buf=bytearray(5)defmeasure(self):buf=self.buf dht_readinto(self.pin,buf)if(buf[0]+buf[1]+buf[2]+buf[3])&0xff!=buf[4]:raiseException("checksum error")classDHT11(DHTBase):defhumidity(self):returnself.buf[0]deftemperature(self):returnself.buf[2]classDHT22(DHTBase):defhumidity(self):return(self.buf[0]<<8|self.buf[1])*0.1deftemperature(self):t=((self.buf[2]&0x7f)<<8|self.buf[3])*0.1ifself.buf[2]&0x80:t=-treturnt
mrequests.py 一个比自带的requests更好用的网络库
六、运行程序
上电直接运行，注意，代码可以去掉终端输出的print，防止ESP32内存溢出
七、监测程序
登录ActiveMQ查看
mqttserver.py 在任意电脑上订阅数据
# python3.6importrandomimporttimefrompaho.mqttimportclientasmqtt_clientbroker='10.0.10.129'port=1883topic="mqtt001"# generate client ID with pub prefix randomlyclient_id=f'python-mqtt-{random.randint(0,100)}'defconnect_mqtt()->mqtt_client:defon_connect(client,userdata,flags,rc):ifrc==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 client.connect(broker,port)returnclientdefsubscribe(client:mqtt_client):defon_message(client,userdata,msg):print(f"Received `{msg.payload.decode()}` from `{msg.topic}` topic "+time.asctime())client.subscribe(topic)client.on_message=on_messagedefrun():client=connect_mqtt()subscribe(client)client.loop_forever()if__name__=='__main__':run()
八、小结
ESP32 MPython太强大了！
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