ESP8266 Community Forum

- Wed Jan 17, 2018 4:22 am #73212 I am trying to send RFID data to an Android app using NodeMCU (ESP8266). Android app is a TCP client socket tester app (Simple TCP Socket Tester) below is the code:

Code: Select all#include <ESP8266WiFi.h>
#include <WiFiClient.h>
#include <WiFiServer.h>
#include <SPI.h>
#include <MFRC522.h>

#define RST_PIN D2
#define SS_PIN D1

MFRC522 mfrc522(SS_PIN, RST_PIN);  // Create MFRC522 instance

const char* ssid ="IoT4143" ;
const char* password ="redminote4";
 
WiFiServer server(81);
 
void setup() {
  Serial.begin(115200);
  delay(10);
  SPI.begin();      // Init SPI bus
  mfrc522.PCD_Init();   // Init MFRC522
  mfrc522.PCD_DumpVersionToSerial();  // Show details of PCD - MFRC522 Card Reader details
 
  // Connection to wireless network
  Serial.println();
  Serial.println();
  Serial.print("Connecting to ");
  Serial.println(ssid);

  //WiFi.config(ip, gateway, subnet);
  WiFi.begin(ssid, password);
 
  while (WiFi.status() != WL_CONNECTED) {
    delay(500);
    Serial.print(".");
  }
  Serial.println("");
  Serial.println("WiFi connected");
  Serial.println(WiFi.localIP());
 
  server.begin();
  server.setNoDelay(true);
  Serial.println("Server started");
}
 
void loop() {
  WiFiClient client = server.available();

  if(client)
  {
    Serial.println("new client");
    while(client.connected())
 {
  if(client.available())
  {
  // Read the first line of the request
  String request = client.readStringUntil('\n');
  Serial.println(request);
  client.setNoDelay(true);
  for(int i=0;i<=10;i++)
  {
    // Look for new cards
  if ( ! mfrc522.PICC_IsNewCardPresent()) {
    return;
  }

  // Select one of the cards
  if ( ! mfrc522.PICC_ReadCardSerial()) {
    return;
  }
  //Show UID on serial monitor
  Serial.println();
  Serial.print(" UID tag :");
  String content= "";
  for (byte i = 0; i < mfrc522.uid.size; i++)
  {
     Serial.print(mfrc522.uid.uidByte[i] < 0x10 ? " 0" : " ");
     Serial.print(mfrc522.uid.uidByte[i], HEX);
     content.concat(String(mfrc522.uid.uidByte[i] < 0x10 ? " 0" : " "));
     content.concat(String(mfrc522.uid.uidByte[i], HEX));
  }
  content.toUpperCase();
  client.print(content);
  delay(2000);
  }
  Serial.println("Client Disconnected");
  client.println("Reading stopped");
  client.stop();
 }
  }
  }
}

 

What I want to achieve is when I send "Readstart" from the app the NodeMCU should send RFID card data until I send "Readstop".

But the problem is when I connect the app to NodeMCU's IP (192.168.43.179) at port 80 it disconnects immediately sometimes and it sends the partial card data (data of 2 cards and disconnects or data of 3 cards and disconnects).

I want n number of cards UIDs until I send "Readstop" string as request. I was trying to achieve it using while loop.

Code: Select allwhile(request!="Readstop")
{
  //rfid code
}

But no data was sent. Then I tried the for loop. This is also not working..

I am attaching screenshot of Mobile app:

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