Temperatuur waarde in een string zetten ?

International Nederlands
1

Hallo

Ik wil 2 waardes uitlezen in home assistent via MQTT
een counter en tempsensor.
De counter werkt maar de (tempC) kan ik niet in de string zetten.....
MQTTclient.publish("DEMO/iWaarde", String(tempC).c_str());
maar met Serial.println(tempC); is de waarde /temperatuur prima te zien


#include <OneWire.h>
#include <DallasTemperature.h>
#include <ESP8266WiFi.h>
#include <ArduinoOTA.h>
#include <PubSubClient.h>
// #include "arduino_secrets.h"
#include <ESP8266mDNS.h>
#include <WiFiUdp.h>

int iWiFiTry = 0;          
int iMQTTTry = 0;
String sClient_id;

int iCount;   // For DEMO
int iWaarde;
// int tempC;
const char* ssid = "";
const char* password = "";
const char* HostName = "Arduino_Mqtt_OTA";

const char* mqtt_broker = "192.168.178.65";
const char* mqtt_user = "mqtt-gebruiker";
const char* mqtt_password = "1234";
#define ONE_WIRE_BUS 12
OneWire oneWire(ONE_WIRE_BUS);
WiFiClient espClient;
PubSubClient MQTTclient(espClient); // MQTT Client
DallasTemperature sensors(&oneWire);

void setup() {
  Serial.begin(115200);
  sensors.begin();
  pinMode(LED_BUILTIN, OUTPUT);
  while (!Serial) { ; }  // wait for serial port to connect. Needed for native USB port only           
  Connect2WiFi();
  Connect2MQTT();
  iCount = 0;
  iWaarde = -129;
  
  // Start up the library
  
}

void Connect2WiFi() { 
  //Connect to WiFi
  // WiFi.mode(WIFI_STA);  //in case of an ESP32
  iWiFiTry = 0;
  WiFi.begin(ssid, password);
  WiFi.setHostname(HostName);
  Serial.print("Connecting to WiFi ");
  while (WiFi.status() != WL_CONNECTED && iWiFiTry < 11) { //Try to connect to WiFi for 11 times
    ++iWiFiTry;
    Serial.print(".");
    delay(500);
  }
  Serial.println("");
  Serial.print("Got IP: ");  Serial.println(WiFi.localIP());
  // ArduinoOTA.setPort(8266); // Port defaults to 8266
  
  ArduinoOTA.setHostname(HostName); 
 // ArduinoOTA.setPassword((const char *)OTAPassword); // Optional password

  ArduinoOTA.onStart([]() { Serial.println("Start"); });
  ArduinoOTA.onEnd([]()   { Serial.println("\nEnd"); });
  ArduinoOTA.onProgress([](unsigned int progress, unsigned int total) {
    Serial.printf("Progress: %u%%\r", (progress / (total / 100)));
  });
  ArduinoOTA.onError([](ota_error_t error) {
    Serial.printf("Error[%u]: ", error);
    if (error == OTA_AUTH_ERROR) Serial.println("Auth Failed");
    else if (error == OTA_BEGIN_ERROR) Serial.println("Begin Failed");
    else if (error == OTA_CONNECT_ERROR) Serial.println("Connect Failed");
    else if (error == OTA_RECEIVE_ERROR) Serial.println("Receive Failed");
    else if (error == OTA_END_ERROR) Serial.println("End Failed");
  });
  ArduinoOTA.begin();
  Serial.println("Ready");

  //Unique MQTT Device name
  sClient_id = "esp-client-" + String(WiFi.macAddress());
  Serial.print("ESP Client name: "); Serial.println(sClient_id);
}

void Connect2MQTT() {
  // Connect to the MQTT server
  iMQTTTry=0;
  if (WiFi.status() != WL_CONNECTED) { 
    Connect2WiFi; 
  }

  Serial.print("Connecting to MQTT ");
  MQTTclient.setServer(mqtt_broker, 1883);
  while (!MQTTclient.connect(sClient_id.c_str(), mqtt_user, mqtt_password) && iMQTTTry < 11) { //Try to connect to MQTT for 11 times
    ++iMQTTTry;
    Serial.print(".");
    delay(500);
  }
  Serial.println("");
}

void loop() {
  ArduinoOTA.handle();

 if (!MQTTclient.connect(sClient_id.c_str(), mqtt_user, mqtt_password)) {
    Connect2MQTT(); }


   digitalWrite(LED_BUILTIN, LOW);  // turn the LED on 
   Serial.println("Begin Loop");    
  MQTTclient.publish("DEMO/iCount", String(iCount).c_str());
  MQTTclient.publish("DEMO/iWaarde", String(tempC).c_str());
  Serial.println(iCount);
  ++iCount;

  if(iCount>99) {
    iCount = 0;
    
    
  }
delay(500);  
digitalWrite(LED_BUILTIN, HIGH);  // turn the LED off
 delay(1500); 

  sensors.requestTemperatures(); // Send the command to get temperatures
    float tempC = sensors.getTempCByIndex(0);
        Serial.println(tempC);
 


    // If you want to reboot your device when WiFi is not working
    if (iWiFiTry > 10){
      Serial.println("REBOOTING");
      Serial.println(" Reboot in 2 seconds");
      Serial.println(""); 
      delay(2000);
      ESP.restart(); 
    }
  }
2

Here you create a new variable. You set the value. But the old variable with the same name will not be updated.
Try to delete 'float'.

3

Hi

the problem is that i get an error
the Compilation error: 'tempC' was not declared in this scope

if i delete -> tempC
MQTTclient.publish("DEMO/iWaarde", String(tempC).c_str());
the error is gone

4

Make tempC global.
Before loop() add:
float tempC;

5

:heart_eyes:

it seems to work -127 C

Now attach a sensor

6

Currently you are reading the temperature after sending the temperature via MQTT...
You will see the first real temperature in the second loop... in the first you should see 0.0.

7

yes I see, not a problem in itself.

this is a clipping of various working sketch parts. Now add a fan controller sketch and then it is complete.

8

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