---
disqus: ahb0222
GA : G-VF9ZT413CG
---
# RS485_Arduino&MQTT應用
> [color=#40f1ef][name=LHB阿好伯, 2023/02/05][:earth_africa:](https://www.facebook.com/LHB0222/)
###### tags: `Arduino` `RS485` `MQTT`

[TOC]

# UART(TTL) 轉 RS485 雙向轉換器
:::success
* 3.3V與5.0V電源完美相容
* 3.3V 和 5.0V 信號完美相容
* 工作溫度範圍：-40 °C 至 + 85 °C
* 傳輸距離可達公里（用850米的2*1.5電纜做測試，建議在800米、800米以上使用，請添加中繼器）
* 郵票孔工藝設計，厚度0.8mm，便於作為組合板使用，也可焊接端子使用
* 具有 RXD、TXD 信號燈，可觀察發送和接收狀態
* 通訊方式：半雙工
:::


bool connectedWiFi  = false;
bool connectedMQTT  = false;
#define WIFI_SSID         "SSID"    // 無線網路名稱
#define WIFI_PASSWORD     "PASSWORD"    //無線網路密碼
#include <WiFi.h>
WiFiMulti multi;
WiFiClient espClient;
#include "PubSubClient.h"
PubSubClient client(espClient);
int status = WL_IDLE_STATUS;
const char* mqttServer = "broker.emqx.io"; // mqtt server address
const int mqttPort = 1883; // mqtt port
const char* mqttUser = ""; // your mqtt user
const char* mqttPassword = ""; // your mqtt password
String clientId = "RP2040WClient-"; // Create a random client ID
void MQTTreconnect()
{  
    if ( (status != WL_CONNECTED)  )
  {
    status = WiFi.begin(WIFI_SSID, WIFI_PASSWORD);
    Serial.println("連接WiFi");
    // delay(500);
     if ( (status != WL_CONNECTED)  )
  {
    Serial.println("未連接WiFi");
    // delay(500);
  }else{
    Serial.println("連接WiFi");
  }
  }  
  if (!client.connected())
  {
    Serial.println("Connecting to MQTT...");
    clientId += String(random(0xffff), HEX);
    if (client.connect(clientId.c_str(), mqttUser, mqttPassword))
    {
      Serial.println("connected");
    }
    else
    {
      Serial.print("failed with state ");
      Serial.print(client.state());
      Serial.println(" try again in 5 seconds");
      delay(5000);
    }
  }
}

#include <WiFi.h>
#include <AsyncMqtt_Generic.h>

const char *PubTopic  = "/test/WS";               //MQTT Topic位址

AsyncMqttClient mqttClient;

void printWifiStatus()
{
  // print the SSID of the network you're attached to:
  Serial.print("Connected to SSID: ");
  Serial.println(WiFi.SSID());

  // print your board's IP address:
  IPAddress ip = WiFi.localIP();
  Serial.print("Local IP Address: ");
  Serial.println(ip);

  // print the received signal strength:
  long rssi = WiFi.RSSI();
  Serial.print("Signal strength (RSSI):");
  Serial.print(rssi);
  Serial.println(" dBm");
}

bool connectToWifi()
{
  // check for the WiFi module:
  if (WiFi.status() == WL_NO_MODULE)
  {
    Serial.println("Communication with WiFi module failed!");
    // don't continue
    while (true);
  }

  Serial.print(F("Connecting to SSID: ")); Serial.println(WIFI_SSID);

#define MAX_NUM_WIFI_CONNECT_TRIES_PER_LOOP       20 

  uint8_t numWiFiConnectTries = 0;
  
  // attempt to connect to WiFi network
  while ( (status != WL_CONNECTED) && (numWiFiConnectTries++ < MAX_NUM_WIFI_CONNECT_TRIES_PER_LOOP) )
  {
    status = WiFi.begin(WIFI_SSID, WIFI_PASSWORD);
    
    delay(500);
  }

  if (status != WL_CONNECTED)
  {
    // Restart for Portenta as something is very wrong
    Serial.println("Resetting. Can't connect to any WiFi");
    
    NVIC_SystemReset();
  }

  printWifiStatus();

  connectedWiFi = (status == WL_CONNECTED);

  return (status == WL_CONNECTED);
}

bool isWiFiConnected()
{
  // You can change longer or shorter depending on your network response
  // Shorter => more responsive, but more ping traffic
  static uint8_t theTTL = 10;

  // Use ping() to test TCP connections
  if (WiFi.ping(WiFi.gatewayIP(), theTTL) == theTTL)
  {
    return true;
  }

  return false;
}
void connectToMqttLoop()
{
  //if ( (WiFi.status() == WL_CONNECTED) && (WiFi.RSSI() != 0) )      // temporary workaround
  if (isWiFiConnected())
  {     
    if (!connectedMQTT)
    {
      mqttClient.connect();
    }

    if (!connectedWiFi)
    {
      Serial.println("WiFi reconnected");
      connectedWiFi = true;
    }
  }
  else
  {          
    if (connectedWiFi)
    {
      Serial.println("WiFi disconnected. Reconnecting");
      connectedWiFi = false;

      connectToWifi();
    }
  }
}




void connectToMqtt()
{
  Serial.println("Connecting to MQTT...");
  mqttClient.connect();
}

void printSeparationLine()
{
  Serial.println("************************************************");
}

void onMqttConnect(bool sessionPresent) 
{
  Serial.print("Connected to MQTT broker: "); Serial.print(MQTT_HOST);
  Serial.print(", port: "); Serial.println(MQTT_PORT);
  Serial.print("PubTopic: "); Serial.println(PubTopic);

  connectedMQTT = true;
  
  printSeparationLine();
  Serial.print("Session present: "); Serial.println(sessionPresent);
  
  uint16_t packetIdSub = mqttClient.subscribe(PubTopic, 2);
  Serial.print("Subscribing at QoS 2, packetId: "); Serial.println(packetIdSub);
  
  mqttClient.publish(PubTopic, 2, true, "RP2040W Test1");
  Serial.println("Publishing at QoS 0");
  printSeparationLine();
}

void onMqttPublish(const uint16_t& packetId)
{
  Serial.println("Publish acknowledged.");
  Serial.print("  packetId: "); Serial.println(packetId);
}
void setup() {
  mySerial.begin(4800);
  Serial.begin(4800);
//  pinMode(RS485De, OUTPUT);
// ---------------Wifi--------------------
  multi.addAP(WIFI_SSID, WIFI_PASSWORD);
  Serial.println("");
  Serial.println("WiFi connected");
  Serial.println("IP address: ");
  Serial.println(WiFi.localIP());
// ------------------MQTT--------------------
client.setBufferSize(512); // option or with need
  client.setServer(mqttServer, mqttPort); // need
  //client.setCallback(callback); // need
  delay(2000);

  MQTTreconnect(); 
  
}

void loop() {
//輸出詢問碼
  mySerial.write((unsigned char)0x01);
  mySerial.write((unsigned char)0x03);
  mySerial.write((unsigned char)0x00);
  mySerial.write((unsigned char)0x00);
  mySerial.write((unsigned char)0x00);
  mySerial.write((unsigned char)0x01);
  mySerial.write((unsigned char)0x84);
  mySerial.write((unsigned char)0x0A);


  delay(500);
//接收資料
  if (mySerial.available() >= 6) {
    unsigned char data[7];
    for  (int i = 0; i < 7; i++) {
    data[i] = mySerial.read();    
} 
//資料轉換
    float value = ((data[3] << 8) | data[4]) / 10.0;
    Serial.println("風速: " + String(value,1) + "m/s"); 
    String strValue = String(value); 
    if (client.publish(PubTopic, strValue.c_str()) == true)
    {
      Serial.println("Success sending message");
    
     
    } 
  } 
  Serial.println("測試");
}




## 外殼

https://1drv.ms/u/s!AuqcoLPA0_SIpflCsQo24oitOeKsuA?e=EN9cY5

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