MQTT Node-red and Arduino

Using Arduino Programming Questions
1

Hi I can't for the life of me understand why i can't send non-boolean values to mqtt (which is connected to node-red). It seems to get stuck on message

//relevant code


void callback(char* topic, byte* message, unsigned int length) {
  Serial.print("Message arrived on topic: ");
  Serial.print(topic);
  Serial.print(". Message: ");
  String messageLading;

  for (int i = 0; i < length; i++) {
    Serial.print((char)message[i]);
    messageLading += (char)message[i];
  }
  Serial.println();

  // Feel free to add more if statements to control more GPIOs with MQTT

  // If a message is received on the topic esp32/output, you check if the message is either "on" or "off".
  // Changes the output state according to the message
  if (String(topic) == "ladestasjon/output") {
    Serial.print("Changing output to ");
    if (messageLading == "charge") {
      Serial.println("on");
      ladBil=true;
    }
    else if (messageLading == "stop") {
      Serial.println("off");
      ladBil=false;
    }
  if (String(topic) == "ladestasjon/BatteriProsent"){
      Serial.print(message);
  
  }
      
  }
}

void reconnect() {
  // Loop until we're reconnected
  while (!client.connected()) {
    Serial.print("Attempting MQTT connection...");
    // Attempt to connect
    if (client.connect("ESP8266Client")) {
      Serial.println("connected");
      // Subscribe
      client.subscribe("ladestasjon/output");
      client.subscribe("ladestasjon/BatteriProsent")
    } else {
      Serial.print("failed, rc=");
      Serial.print(client.state());
      Serial.println(" try again in 5 seconds");
      // Wait 5 seconds before retrying
      delay(5000);
    }
  }
}
2

Your topic was MOVED to its current forum category as it is more suitable than the original

What is "it" and what makes you think that it is struck ?

What exactly are you sending to MQTT ?

3

I'm simulating a software battery for a ZUMO32U4 car. I want to send (through MQTT) what the battery percentage currently is to Node-red. Also I'm using an esp32 to connect to node-red

4

I do not see any publishing code, could you post your publishing code?

No, that's not all the relevant code. client.loop() and how it's being done is very very relevant to receiving the MQTT callback.

Post all your code.

Serial.prints from the callback, outside of troubleshooting, are considered a bad idea.

Post all your code.

Checks for a MQTT connection but does not check for a WiFI connection. If the WiFI is NOT connected and a check for WiFi connection is not done and something done about a disconnected WiFi, then how do you expect MQTT to connect?

The OP might consider putting the MQTT callback into IRAM (IRAM_ATTR) for faster callback operations.


void IRAM_ATTR mqttCallback(char* topic, byte * payload, unsigned int length)
{
  memset( x_message.payload, '\0', payloadSize ); // clear payload char buffer
  x_message.topic = ""; //clear topic string buffer
  x_message.topic = topic; //store new topic
  int i = 0; // extract payload
  for ( i; i < length; i++)
  {
    x_message.payload[i] = (char)payload[i];
  }
  x_message.payload[i] = '\0';
  xQueueOverwrite( xQ_Message, (void *) &x_message );// send data to queue
} // void mqttCallback(char* topic, byte* payload, unsigned int length)
////

In this ESP32 freeRTOS task you should be able to see a publish.

void fReadCurrent( void * parameter )
{
  const TickType_t xFrequency = 1000; //delay for mS
  const float mVperAmp        = 185.0f;
  float    ADbits             = 4096.0f;
  float    ref_voltage        = 3.3f;
  float    mA                 = 0.0f;
  float    adcValue           = 0.0f;
  float    Voltage            = 0.0f;
  float    Power              = 0.0f;
  float    offSET             = 0.0f;
  int      printCount         = 0;
  uint64_t TimePastKalman     = esp_timer_get_time(); // used by the Kalman filter UpdateProcessNoise, time since last kalman calculation
  SimpleKalmanFilter KF_I( 1.0f, 1.0f, .01f );
  /*
     185mv/A = 5 AMP MODULE
     100mv/A = 20 amp module
     66mv/A = 30 amp module
  */
  String powerInfo = "";
  powerInfo.reserve( 150 );
  while ( !MQTTclient.connected() )
  {
    vTaskDelay( 250 );
  }
  TickType_t xLastWakeTime = xTaskGetTickCount();
  for (;;)
  {
    adc1_get_raw(ADC1_CHANNEL_3); // read once discard reading
    adcValue = ( (float)adc1_get_raw(ADC1_CHANNEL_3) );
    //log_i( "adcValue I = %f", adcValue );
    Voltage = ( (adcValue * ref_voltage) / ADbits ) + offSET; // Gets you mV
    mA = Voltage / mVperAmp; // get amps
    KF_I.setProcessNoise( (esp_timer_get_time() - TimePastKalman) / 1000000.0f ); //get time, in microsecods, since last readings
    mA = KF_I.updateEstimate( mA ); // apply simple Kalman filter
    TimePastKalman = esp_timer_get_time(); // time of update complete
    printCount++;
    if ( printCount == 60 )
    {
      xSemaphoreTake( sema_CalculatedVoltage, portMAX_DELAY);
      Power = CalculatedVoltage * mA;
      //log_i( "Voltage=%f mA=%f Power=%f", CalculatedVoltage, mA, Power );
      printCount = 0;
      powerInfo.concat( String(CalculatedVoltage, 2) );
      xSemaphoreGive( sema_CalculatedVoltage );
      powerInfo.concat( ",");
      powerInfo.concat( String(mA, 4) );
      powerInfo.concat( ",");
      powerInfo.concat( String(Power, 4) );
      xSemaphoreTake( sema_MQTT_KeepAlive, portMAX_DELAY );
      MQTTclient.publish( topicPower, powerInfo.c_str() ); //!!!!!!!!!!!!!!!!!!! PUBLISH!!!!!!!
      xSemaphoreGive( sema_MQTT_KeepAlive );
      powerInfo = "";
    }
    xLastWakeTime = xTaskGetTickCount();
    vTaskDelayUntil( &xLastWakeTime, xFrequency );
  }
  vTaskDelete( NULL );
} //void fReadCurrent( void * parameter )
////
5

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