Send sensors data from (NodeMCU) ESP8266 to node red via mqtt

[damselindisguise99]

I am trying to send my temperature and heart rate readings collected on the Arduino Uno board to ESP8266 which will then transmit these sensor readings to Node-Red using MQTT.

The following are my Arduino codes to receive the sensor readings.

#define USE_ARDUINO_INTERRUPTS true 
#include <PulseSensorPlayground.h>

const int PulseWire=0;
int Threshold=550;
PulseSensorPlayground pulseSensor;
int myBPM;
int tempPin=1;
int val;
float cel;

void setup() {
  // put your setup code here, to run once:
  Serial.begin(9600);
  pulseSensor.analogInput(PulseWire);
  pulseSensor.setThreshold(Threshold);

  if(pulseSensor.begin()){
    Serial.println("We created a PulseSensor Object!");
    }
  
}

void loop() {
  // put your main code here, to run repeatedly:
    int myBPM =pulseSensor.getBeatsPerMinute();
    if(pulseSensor.sawStartOfBeat()){
    Serial.print("BPM:");
    Serial.println(myBPM);
    
    delay(500);
   val=analogRead(tempPin);
   float mv=(val/1024.0)*500;
   float cel=mv/10;
   Serial.print("TEMPERATURE: ");
   Serial.println(cel);
    
    }
  delay(500);
}

The following sketch is used to program the nodemcu

 #include <SoftwareSerial.h>
#include <ESP8266WiFi.h>
#include <PubSubClient.h>

SoftwareSerial NodeMcu_SoftSerial (D6,D5); //Rx,Tx pins
int myBPM;
float cel;

  //Use a hotspot
const char* ssid = "kickyourass_5G";
const char* password = "mypassword";
const char* mqtt_server = "192.168.1.118";
#define mqtt_user "mabel"
#define mqtt_password "topsecret"


// Timers auxiliar variables
long now = millis();
long lastMeasure = 0;

WiFiClient espClient;
PubSubClient client(espClient);

void setup_wifi() {
  delay(10);
  // We start by connecting to a WiFi network
  Serial.println();
  Serial.print("Connecting to ");
  Serial.println(ssid);
  WiFi.begin(ssid,password);
  
  while (WiFi.status() != WL_CONNECTED) {
    delay(500);
    Serial.print(".");
  }

  Serial.println("");
  Serial.println("WiFi connected");
  Serial.println("IP address: ");
  Serial.println(WiFi.localIP());
}

void callback(char* topic, byte* payload, unsigned int length) {
  Serial.print("Message arrived [ ");
  Serial.print(topic);
  Serial.print("] ");
  
  for (int i = 0; i < length; i++) {
    Serial.print((char)payload[i]);
  }
  Serial.println();
}


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");
      // Once connected, publish an announcement...
      //client.publish("AshesiOutTopic","Welcome to Mabel's World");
      // ... and resubscribe
      //client.subscribe("AshesiOutTopic");
    } else {
      Serial.print("failed, rc=");
      Serial.print(client.state());
      Serial.println(" try again in 5 seconds");
      // Wait 5 seconds before retrying
      delay(5000);
    }
  }
}

void setup() {
  // put your setup code here, to run once:
    Serial.begin (115200);
    NodeMcu_SoftSerial.begin (9600);
    setup_wifi();
    client.setServer(mqtt_server, 1883);
    client.setCallback(callback);
    
    // Allow the hardware to sort itself out
    delay(1500);
}

void loop() {
  // put your main code here, to run repeatedly:
 // String msg = NodeMcu_SoftSerial.readStringUntil('\r');
  //Serial.println(msg);
 // String myBPM_str= NodeMcu_SoftSerial.readStringUntil('\n');
  //int myBPM= myBPM_str.toInt();
  //Serial.println(myBPM_str);
  if (!client.connected()) {
    reconnect();
  }
  if(!client.loop())
  client.connect("ESP8266Client");
  now = millis();
  if (now-lastMeasure>30000){ 
    lastMeasure = now;
    while(NodeMcu_SoftSerial.available()>0){
      myBPM=NodeMcu_SoftSerial.parseInt();
      cel=NodeMcu_SoftSerial.parseFloat();

 // Check if any reads failed and exit early (to try again).
    if (isnan(myBPM) || isnan(cel)) {
      Serial.println("Failed to read from sensors!");
      return;
    }

      
      String myBPM_Values= String(myBPM);
      Serial.print("BPM:");
      Serial.println(myBPM_Values);
      client.publish("sensor/HeartRate",myBPM_Values.c_str());
      
      cel=NodeMcu_SoftSerial.parseFloat();
      String celValues=String(cel);
      Serial.print("TEMPERATURE:");
      Serial.println(celValues);
      client.publish("sensor/temperature",celValues.c_str());
     }
     client.subscribe("HeartRateValues");
     client.subscribe("TemperatureValues");
  }
}

however, I keep getting results like these on the nodemcu serial monitor.

I am still very new to how MQTT works so any help would be useful.

[pylon]

@damselindisguise99

I am still very new to how MQTT works so any help would be useful.

The only code part that outputs a series of dots is wait for a WiFi connection. I guess you have a problem there.

Do you have complete serial output?