Serial communication between two NodeMCUs

Projects Programming
1

Hey everyone.. I am working on a project that has two temperature sensors each connected to individual NodeMCUs. One acts as a slave and other a master. The slave has to send the sensor data to the master through serial communication and master combines the slave's data and its own data. I have used Software Serial for communication. What I need is the master has to wait for the slave to send the data and then print it in the serial monitor. I tried using

while (!serial.available());

, but it doesnt work as I needed.
This is the snippet of Master's Code:

void temp_monitor_master()
float C_tot;
float C_avg, temp;
int input=1, sample=20;
String string_Cavg;
{
    for(int i=1; i<=20 ; i++){
     C_tot=C_tot+mlx.readObjectTempC();
      delay(100);
    }
    C_avg=C_tot/20;
    C_avg = 60;
    if((sample>5 && sample <100) && (C_avg>20 && C_avg<100) ){
   string_Cavg=String(C_avg,1);
   Serial.println(string_Cavg);
  Serial.println("Controller 1 (Master)");
    Serial.print("<0"); Serial.print(sample);
    Serial.print(" 0"); Serial.print(C_avg);
    Serial.print(">");
    while (serial1.available()<1);
{   
    Serial.println(serial1.readStringUntil('n'));  
    }
    C_avg=0;
    C_tot=0;
    }
}

The code Slave:

int C_tot;
int C_avg, temp;
int input, sample=20;
String str;

void temp_monitor_slave(){
  
    for(int i=1; i<=20 ; i++){
    C_tot=C_tot+mlx.readObjectTempC();
    delay(100);
    }
       C_avg=C_tot/20;
Serial.print("nAv/erage Celsius = ");
    Serial.print(C_avg);
    Serial.println("*C");
    if((sample>5 && sample <100) && (C_avg>20 && C_avg<100) ){
    str = String("(0") + String (sample) + String(" 0") +  String(C_avg) + String(")");
    Serial.println(str);
    serial1.print(str);
    C_avg=0;
    C_tot=0;
    }
}

Thanks in advance...

2

HARICHOZHAN:
I have used Software Serial for communication.

I have seen no evidence of that at all, but since you are only showing snippets it is a little hard to tell.
What you are saying is that the slave sends the data and the master receives and combines. The unit that sends data all by itself i would call a master, so unless you get your "master" to send a request for data i would call that a slave. There are good reliable & non-blocking serial communication method examples here 'Serial Input Basics'
btw what is the reason to use 2 nodeMCU's to acquire data ?