RC522 with ESP8266 not working Arduino uno

Question

I have written below code for Arduino Uno to scan an RFID card using a RC522 module and an ESP8266 module to connect to my router.

Now when I scan any card it should read the card number and send a request to my server's IP address and get the response.

But after successfully reading the RFID card, the connection to the server via TCP does not work:

esp.println("AT+CIPSTART=\"TCP\",\"" + server + "\",80");//start a TCP connection.

So I am not able to send a request to my server.

But when I remove the RC522 code (for testing) it is working!

What is the problem using the RC522 and the ESP8266 together?

#include <SPI.h>
#include <MFRC522.h>
#include "SoftwareSerial.h"

#include <Wire.h>
#include <LiquidCrystal_I2C.h>

//I2C pins declaration
LiquidCrystal_I2C lcd(0x3F, 2, 1, 0, 4, 5, 6, 7, 3, POSITIVE);

#define SS_PIN 9
#define RST_PIN 7
#define mainLock 2


String ssid = "MYSSID";
String password = "PASSWORD";

SoftwareSerial esp(2, 3);// RX, TX
String server = "192.168.1.102"; //Your Host
String uri = "/get_data.php?rfid_key=";

//#define LED_G 4 //define green LED pin
//#define LED_R 5 //define red LED
#define BUZZER 6 //buzzer pin

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

String rfidUid = "";

#define DEBUG true

void setup()
{
  //  Serial.begin(9600);   // Initiate a serial communication

  esp.begin(9600);

  Serial.begin(9600);

  SPI.begin();      // Initiate  SPI bus
  mfrc522.PCD_Init();   // Initiate MFRC522

  connectWifi();

  httpget();

  delay(1000);

  Serial.println("Put your card to the reader...");
  Serial.println();

  pinMode(mainLock, OUTPUT);

  lcd.begin(16, 2); //Defining 16 columns and 2 rows of lcd display
  lcd.backlight();//To Power ON the back light

}

void connectWifi() {

  sendData("AT+RST\r\n", 2000, DEBUG);          //This command will reset module to default
  sendData("AT+CWMODE=3\r\n", 1000, DEBUG);

  String cmd = "AT+CWJAP=\"" + ssid + "\",\"" + password + "\"";

  esp.println(cmd);

  delay(4000);

  if (esp.find("OK")) {
    Serial.println("Connected!");
  }
  else {
    Serial.println("Cannot connect to wifi ! Connecting again...");
    connectWifi();
  }


}

/////////////////////////////GET METHOD///////////////////////////////
void httpget() {
//  // 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.print("UID tag :");
  String content = "";
  byte letter;

  rfidUid = "";
  for (byte i = 0; i < mfrc522.uid.size; i++)
  {
    Serial.print(mfrc522.uid.uidByte < 0x10 ? " 0" : " ");
    Serial.print(mfrc522.uid.uidByte, HEX);
    content.concat(String(mfrc522.uid.uidByte < 0x10 ? " 0" : " "));
   content.concat(String(mfrc522.uid.uidByte, HEX));

    rfidUid += String(mfrc522.uid.uidByte < 0x10 ? "0" : "");
   rfidUid += String(mfrc522.uid.uidByte, HEX);

  }

  Serial.println();
  content.toUpperCase();

  lcd.clear();
  lcd.setCursor(0, 0);
  lcd.print(rfidUid);

  esp.println("AT+CIPSTART=\"TCP\",\"" + server + "\",80");//start a TCP connection.

  if ( esp.find("OK")) {

    Serial.println("TCP connection ready");

  } delay(1000);

     if ( esp.find("OK")) {

    Serial.println("TCP connection ready");

    } delay(1000);

    String getRequest =
      "GET " + uri + rfidUid + " HTTP/1.0\r\n" +
      "Host: " + server + "\r\n" +
      "Accept: *" + "/" + "*\r\n" +
      "Content-Type: text/plain\r\n" +
      "\r\n";

   String sendCmd = "AT+CIPSEND=";

   esp.print(sendCmd);

    esp.println(getRequest.length());

  delay(500);

   if (esp.find(">")) {

     Serial.println("Sending..");

      esp.print(getRequest);

      if (esp.find("SEND OK")) {

        Serial.println("Packet sent");

        while (esp.available()) {

         String response = esp.readString();

         Serial.println("response.." + response);

        }
        esp.println("AT+CIPCLOSE");
     }
   }

}

void loop()
{
  httpget();


}


String sendData(String command, const int timeout, boolean debug) // Function to send the data to the esp8266
{
  String response = "";
  esp.print(command);           // Send the command to the ESP8266
  long int time = millis();
  while ( (time + timeout) > millis()) // ESP8266 will wait for some time for the data to receive
  {
    while (esp.available())     // Checking whether ESP8266 has received the data or not
    {
      char c = esp.read();      // Read the next character.
      response += c;                // Storing the response from the ESP8266
    }
  }
  if (debug)
  {
    Serial.print(response);         // Printing the response of the ESP8266 on the serial monitor.
  }
  return response;
}

Forum link - https://forum.arduino.cc/index.php?topic=538180.0

Answer 1

Unfortunately you are not showing the differences between the code that is working (partially, TCP connection) and the one that is not (at all, or just the TCP connection?).

when i remove the Rc522 code testing then it is working !

Just try to describe what is working and what isn't a little more in detail. You could also provide your debug output and add some comments.

Also I'd try removing more non-essential code (like the display) to help narrow down the cause. This might already get you on the right track to fix it yourself, but it would also make your code here easier to read (also see How to create a Minimal, Complete, and Verifiable example though I doubt many will have the exact parts to reproduce your problem - but you might get lucky).

But, from the code you've provided, here's just a guess:

The Arduino might not be receiving data from the ESP8266 module because you are reconfiguring the RX pin as output (but you're not using it!?):

#define mainLock 2
...
pinMode(mainLock, OUTPUT);

conflicts with

SoftwareSerial esp(2, 3);// RX, TX

So I'd recommend double-checking your pin use and connections (also, providing this information would increase your chances of somebody spotting an error).