Posting three parameters to EMQX MQTT

Projects General Guidance
1

I have to publish three variables which have a width of 5 and precision of 2.

I am using this function to convert from float to char string -

dtostrf(floatVar1, 5, 2, charBuf1);

I now need to publish the charBuf1, charBuf2, charBuf3 to the MQTT broker . I tried ,
client.publish( topic, charBuf1);

But it threw an error. I am using the ESP32 chip and PubSubClient library.

Need help. Thanks

2

Start by reading the advice here: How to get the best out of this forum - Using Arduino / Project Guidance - Arduino Forum

3

Wow .. that helped. Appreciate your guidance !!

4

So this one did the job and now I can publish the "postValue" to the MQTT broker and all good !!

void readBME280() {

  tempC = bme.readTemperature();
  tempF = (1.8 * tempC + 32);
  press_hPa = bme.readPressure() / 100;
  humid_percent = bme.readHumidity();
  elevation_m = bme.readAltitude(SEALEVELPRESSURE_HPA);

  dtostrf(tempC, 2, 2, charBuf);
  dtostrf(tempF, 3, 2, charBuf1);
  dtostrf(press_hPa, 4, 2, charBuf2);
  dtostrf(humid_percent, 2, 2, charBuf3);
  dtostrf(elevation_m, 4, 2, charBuf4);

  strcpy(postValue, charBuf);
  strcat(postValue, " ; ");
  strcat(postValue, charBuf1);  
  strcat(postValue, " ; ");
  strcat(postValue, charBuf2); 
  strcat(postValue, " ; ");
  strcat(postValue, charBuf3); 
  strcat(postValue, " ; ");
  strcat(postValue, charBuf4); 
  
  Serial.println(postValue); 

}