#定义MQTT_MAX_PACKET_SIZE 4096

https://api.thingspeak.com/update?api_key=your_write_api_key& field1=angle_value.

#include  #include  //只在使用安全连接时需要。#include  #include  #include "mqtt_secrets.h" #define ANGLE_FIELD 0 #define DATA_FIELD 1 //发送信号强度的数据字段。

char ssid [] =“still_waters_nest”;//将其更改为您的网络SSID（名称）。char pass [] =“33turkeys511”;//将其更改为您的网络密码。const char * server =“mqtt3.thingspeak.com”;char mqttusername [] = secret_mqt_username;char mqttpass [] = secret_mqt_password;//从帐户> myprofile的MQTT API密钥更改为您的MQTT API密钥。char clientID [] = secret_mqt_client_id;长readchannelid = 85; long writeChannelID = 86; // Here's how to get ThingSpeak server fingerprint: https://www.a2hosting.com/kb/security/ssl/a2-hostings-ssl-certificate-fingerprints const char* thingspeak_server_fingerprint = "27 18 92 dd a4 26 c3 07 09 b9 7a e6 c5 21 b9 5b 48 f7 16 e1"; // WiFiClient client; // Initialize the Wi-Fi client library. Uncomment for nonsecure connection. WiFiClientSecure client; // Uncomment for secure connection. PubSubClient mqttClient( client ); // Initialize the PuBSubClient library. Servo myservo; // Create servo object to control a servo . int fieldsToPublish[8]={1,1,0,0,0,0,0,0}; // Change to allow multiple fields. float dataToPublish[8]; // Holds your field data. int changeFlag=0; // Let the main loop know there is new data to set. int servo_pos=0; // Servo position

// //原型// //处理来自MQTT订阅的消息。void mqttSubscriptionCallback(char* topic, byte* payload, unsigned int length);//生成唯一的客户端ID并连接到MQTT代理。空白mqttConnect ();//从ThingSpeak频道订阅一个字段或feed。int mqttSubscribe(long subChannelID,int field, int不明名);//将消息发布到通道提要。//连接到指定的Wi-Fi SSID。int connectWifi ();//测量Wi-Fi信号强度。 void updateRSSIValue();

void setup（）{serial.begin（115200）;serial.println（“开始”）;int status = wl_idle_status;//设置临时Wi-Fi状态。connectwifi（）;//连接到Wi-Fi网络。// mqttclient.setserver（服务器，1883）;//设置MQTT Broker详细信息，不确定端口。非法连接的取消注释。mqttclient.setserver（服务器，8883）; // Set the MQTT broker details, secure port. Uncomment for secure connection. mqttClient.setCallback( mqttSubscriptionCallback ); // Set the MQTT message handler function. myservo.attach(14); // Attach the servo on GIO2 to the servo object. myservo.write(90); // Start in the middle. }

void循环（）{if（wifi.status（）！= wl_connected）{connectwifi（）;}如果（！mqttclient.connected（））{mqttconnect（）;// Connect如果未连接MQTT客户端。if（mqttsubscribe（readchannelid，1,0）== 1）{serial.println（“订阅”）;mqttclient.loop（）;//调用循环以维护与服务器的连接。if（（servo_pos> 175）||（servo_pos <0））{servo_pos = 0;}如果（changeflag）{chanceflag = 0;myservo.write（servo_pos）;DataTopublish [Anight_Field] = servo_pos; delay(1100); // Wait for ThingSpeak to publish. Serial.println( "Servo value " + String( servo_pos ) ); mqttPublish( writeChannelID, dataToPublish, fieldsToPublish ); } delay(1); }

/** *处理通过MQTT代理从订阅通道接收的消息。* topic -消息的订阅主题。*有效载荷-要订阅的字段。值0表示订阅所有字段。* mesLength -消息长度。*/ void mqttSubscriptionCallback(char* topic, byte* payload, unsigned int mesLength) {char p[mesLength + 1];memcpy(p, payload, mesLength);p [mesLength] =零;系列。print("Answer: "); Serial.println( String(p) ); servo_pos=atoi( p ); changeFlag=1; }

void mqttConnect(){//循环直到连接。while (!mqttClient.connected());println(String(mqttUserName)+ "， " + mqttPass + "， " + clientID);//连接到MQTT代理。系列。print("尝试MQTT连接…")；如果(mqttClient。connect(clientID, mqttUserName, mqttPass);println("Connected with Client ID: "+String(clientID) + " User "+String(mqttUserName) + " Pwd "+String(mqttPass));} else {Serial。print( "failed, rc = " ); // See https://pubsubclient.knolleary.net/api.html#state for the failure code explanation. Serial.print( mqttClient.state() ); Serial.println( " Will try again in 5 seconds" ); delay( 5000 ); } } }

/** *订阅频道字段。* subChannelID -订阅的频道。* field -要订阅的字段。值0表示订阅所有字段。* readKey -读取订阅通道的API密钥。*不明嫌犯-设置为1取消订阅。*/ int mqttSubscribe(long subChannelID, int field, int unsubSub){String myTopic;//没有字段0，所以如果字段0被发送到订阅，那么就订阅整个频道提要。if (field==0){myTopic="频道/"+String(subChannelID)+"/subscribe";} else{myTopic="channels/"+String(subChannelID)+"/subscribe/fields/field"+String(field); } Serial.println( "Subscribing to " +myTopic ); Serial.println( "State= " + String( mqttClient.state() ) ); if ( unsubSub==1 ){ return mqttClient.unsubscribe(myTopic.c_str()); } return mqttClient.subscribe( myTopic.c_str() ,0 ); }

/** * Unsubscribe channel * subChannelID -取消订阅的频道。*字段-取消订阅的字段。值0表示订阅所有字段。* readKey -读取订阅通道的API密钥。*/ int mqttUnSubscribe(long subChannelID,int field,char* readKey){String myTopic;if (field==0){myTopic="频道/"+String(subChannelID)+"/subscribe";} else{myTopic="channels/"+String(subChannelID)+"/subscribe/fields/field"+String(field);} mqttClient返回。退订(myTopic.c_str ());}

/ ** *发布到频道* pubchannelid  - 频道发布到。* pubwriteakikey  - 写通道的API键发布到。* dataArray  - 二进制数组，指示要发布的字段，以字段1. * fialeArray  - 要发布的值数组，以字段1. * / void mqttpublish（long pubchannelid，float dataArray []，int fieldarray []）{int index = 0;string datastring =“”;updaterssiveue（）;//确保更新了存储的值。//虽然（索引<8）{//查看字段数组以构建发布字符串以发送到thingspeak。if（FieldArray [index]> 0）{dataString + =“＆字段”+字符串（索引+ 1）+“=”+字符串（dataArray [index]）;}索引++; } Serial.println( dataString ); // Create a topic string and publish data to ThingSpeak channel feed. String topicString ="channels/" + String( pubChannelID ) + "/publish"; mqttClient.publish( topicString.c_str(), dataString.c_str() ); Serial.println( "Published to channel " + String( pubChannelID ) ); }

int connectwifi（）{whifi.status（）！= wl_connected）{wifi.begin（ssid，pass）;延迟（8500）;serial.println（“连接到Wi-Fi”）;serial.println（“连接”）;client.setfingerprint（thingspeak_server_fingerrint）;//如果使用非线性连接，则评论此行。}

void updateRSSIValue(){long rssi = WiFi.RSSI();系列。打印(“RSSI:”);以(rssi);datatoppublish [DATA_FIELD]=float(rssi);}