[SOLVED] Unique (MAC) identification of a nodemcu

Solved
1

Is there a way to identify different nodemcu devices.
Suppose i have many nodemcu devices, how to i uniquely identify each of them?

2

With a label maker or marker pen? :stuck_out_tongue_winking_eye:

But seriously, there can be many ways via code, and of course with Blynk, each will have a unique Auth token.

Basicly you need to explain the context in which you need them identified.

1 Like
3

can you tellme any other ways via code other than with the auth token?

4

Again, totally depends on the context of the situation.

A visual way would be to have a simple flash code for an LED

5

@suhanichandrag Google has the answer to all your general ESP questions but here’s some code for you to study:

/* MACaddress.ino for  https://community.blynk.cc/t/unique-identification-of-a-nodemcu/15915/3  
  
   MAC 5c:cf:7f:d0:92:83 https://www.vultr.com/tools/mac-converter/?mac_address=5c%3Acf%3A7f%3Ad0%3A92%3A83
   is decimal 102046272361091     decimal blocks 92 207 127 208 146 131 

   MACdecimal = MAC_array[0] * pow(256,5);                  = 101155069755392
   MACdecimal = MACdecimal + MAC_array[1] * pow(256,4);     =    889058230272   total 102044127985664
   MACdecimal = MACdecimal + MAC_array[2] * pow(256,3);     =      2130706432   total 102046258692096
   MACdecimal = MACdecimal + MAC_array[3] * pow(256,2);     =        13631488   total 102046272323584 
   MACdecimal = MACdecimal + MAC_array[4] * pow(256,1);     =           37376   total 102046272360960 
   MACdecimal = MACdecimal + MAC_array[5];                  =             131   total 102046272361091 
*/

#include <ESP8266WiFi.h>

uint8_t MAC_array[6];
char MAC_char[18];
unsigned long long MACdecimal;

void setup() {
    Serial.begin(115200);
    Serial.println("\n");

    Serial.print("ESP MAC in decimal blocks: ");
    WiFi.macAddress(MAC_array);
    for (int i = 0; i < sizeof(MAC_array); ++i){
      Serial.print(MAC_array[i]);
      Serial.print("  ");  
    }
    Serial.println();
                   
    Serial.print("ESP MAC is: ");
    for (int i = 0; i < sizeof(MAC_array); ++i){
      MACdecimal = MACdecimal + MAC_array[i] * pow(256,(5 - i));
      if(i < sizeof(MAC_array) - 1)
      {
        sprintf(MAC_char,"%s%02x:",MAC_char,MAC_array[i]);  
      }
      else
      {
        sprintf(MAC_char,"%s%02x",MAC_char,MAC_array[i]);
      }
    }
  
    Serial.println(MAC_char);
    
    /* obtain your decimal MAC from https://www.vultr.com/tools/mac-converter
    and enter the EUI-48 integer value in the if statement below */
    if(MACdecimal == 102046272361091L)  // test by changing the last 91L to 92L
    {
      Serial.println("MAC matches");
    }
    else{
      Serial.println("MAC does not match");
    }
}

void loop() {
  
}

Serial Monitor

ESP MAC in decimal blocks: 92  207  127  208  146  131  
ESP MAC is: 5c:cf:7f:d0:92:83
MAC matches
2 Likes
6

Thankyou! It helps