GSM PIN Management

This example is part of the tools supplied for the Arduino GSM Shield and helps you change or remove the PIN of a SIM card .

Hardware Required

Circuit

image of the Arduino GSM Shield on top of an Arduino or Genuino board

Code

First, import the GSM library

#include <GSM.h>

Initialize an instance of the GSMPin class.

GSMPIN PINManager;

Create your variables, starting with a String to hold input from the serial monitor. Also make a flag for checking f the SIM has been authenticated with a valid PIN, and messages for the serial monitor.

String user_input = "";

boolean auth = false;

String oktext = "OK";
String errortext = "ERROR";

In setup, open a serial connection to the computer. After opening the connection, send a message to the Serial Monitor indicating the sketch has started. Call PINManager.begin() to reset the modem.

void setup(){
  Serial.begin(9600);
  Serial.println("Change PIN example\n");
  PINManager.begin();

Check to see if the SIM is locked with a PIN

while(!auth){
    int pin_query = PINManager.isPIN();
    if(pin_query == 1)
    {

If locked, ask for the PIN via the serial monitor. You'll use a custom function named readSerial() to parse the information.

Serial.print("Enter PIN code: ");
      user_input = readSerial();

If the PIN is valid, set the auth flag to true. Send a status message to the serial monitor indicating the result. If you enter the wrong PIN, you can try again. After 3 missed attempts, the PIN will be locked, and you'll need the PUK number to unlock.

if(PINManager.checkPIN(user_input) == 0)
      {
        auth = true;
        PINManager.setPINUsed(true);
        Serial.println(oktext);
      }
      else
      {  
        Serial.println("Incorrect PIN. Remember that you have 3 opportunities.");
      }
    }

If the SIM is in PUK lock mode, ask for the PUK code and a new PIN

else if(pin_query == -1)
    {
      Serial.println("PIN locked. Enter PUK code: ");
      String puk = readSerial();
      Serial.print("Now, enter a new PIN code: ");
      user_input = readSerial();
      if(PINManager.checkPUK(puk, user_input) == 0)
      {
        auth = true;
        PINManager.setPINUsed(true);
        Serial.println(oktext);
      }
      else
      {
        Serial.println("Incorrect PUK or invalid new PIN. Try again!.");
      }
    }

If there is an error, and the PIN number and PUK are both locked, send an appropriate status message :

else if(pin_query == -2)
    {
      Serial.println("PIN & PUK locked. Use PIN2/PUK2 in a mobile phone.");
      while(true);
    }

If there's no PIN number, set the auth flag to true

else
    {
      // SIM does not requires authetication
      Serial.println("No pin necessary.");
      auth = true;
    }
  }

Check the registration on the GSM network, and indicate if you're connected or not, and if you're roaming.

Serial.print("Checking register in GSM network...");
  if(PINManager.checkReg() == 0)
    Serial.println(oktext);
  else if(PINManager.checkReg() == 1)
    Serial.println("ROAMING " + oktext);  
  else
  {
    Serial.println(errortext);
    while(true);
  }
}

You're going to create a custom function to handle serial input from the serial monitor. Make a named function of type String.

String readSerial()
{

While there is serial information available, read it into a new String. If a newline character is encountered, return to the main program.

String text = "";
  while(1)
  {
    while (Serial.available() > 0)
    {
      char inChar = Serial.read();
      if (inChar == '\n')
      {
        return text;
      }
      if(inChar!='\r')
        text += inChar;
    }
  }
}

loop() acts as a PIN management tool, allowing you to turn the PIN on or off, and change it.

void loop()
{

  Serial.println("Choose an option:\n1 - On/Off PIN.");
  if(PINManager.getPINUsed())
    Serial.println("2 - Change PIN.");
  String user_op = readSerial();
  if(user_op == "1")
  {
    Serial.println("Enter your PIN code:");
    user_input = readSerial();

    PINManager.switchPIN(user_input);
  }
  else if(user_op == "2" & PINManager.getPINUsed())
  {
    Serial.println("Enter your actual PIN code:");
    String oldPIN = readSerial();
    Serial.println("Now, enter your new PIN code:");
    String newPIN = readSerial();

    PINManager.changePIN(oldPIN, newPIN);
  }
  else
  {
    Serial.println("Incorrect option. Try again!.");
  }
  delay(1000);
}

Once your code is uploaded, open the serial monitor to work with the PIN.

The complete sketch is below.

/*
 Band Management

 This sketch, for the Arduino GSM shield, checks the band
 currently configured in the modem and allows you to change
 it.

 Please check http://www.worldtimezone.com/gsm.html
 Usual configurations:
 Europe, Africa, Middle East: E-GSM(900)+DCS(1800)
 USA, Canada, South America: GSM(850)+PCS(1900)
 Mexico: PCS(1900)
 Brazil: GSM(850)+E-GSM(900)+DCS(1800)+PCS(1900)


 Circuit:
 * GSM shield

 created 12 June 2012
 by Javier Zorzano, Scott Fitzgerald

 This example is in the public domain.
 */


// libraries
#include <GSM.h>

// initialize the library instance
GSMBand band;

void setup() {
  // initialize serial communications and wait for port to open:
  Serial.begin(9600);
  while (!Serial) {
    ; // wait for serial port to connect. Needed for Leonardo only
  }

  // Beginning the band manager restarts the modem
  Serial.println("Restarting modem...");
  band.begin();
  Serial.println("Modem restarted.");

};


void loop() {
  // Get current band
  String bandName = band.getBand(); // Get and print band name
  Serial.print("Current band:");
  Serial.println(bandName);
  Serial.println("Want to change the band you’re on?");
  String newBandName;
  newBandName = askUser();
  // Tell the user what we are about to do…
  Serial.print("\nConfiguring band ");
  Serial.println(newBandName);
  // Change the band
  boolean operationSuccess;
  operationSuccess = band.setBand(newBandName);
  // Tell the user if the operation was OK
  if (operationSuccess) {
    Serial.println("Success");
  } else {
    Serial.println("Error while changing band");
  }

  if (operationSuccess) {
    while (true);
  }
}

// This function offers the user different options
// through the Serial interface
// The user selects one
String askUser() {
  String newBand;
  Serial.println("Select band:");
  // Print the different options
  Serial.println("1 : E-GSM(900)");
  Serial.println("2 : DCS(1800)");
  Serial.println("3 : PCS(1900)");
  Serial.println("4 : E-GSM(900)+DCS(1800) ex: Europe");
  Serial.println("5 : GSM(850)+PCS(1900) Ex: USA, South Am.");
  Serial.println("6 : GSM(850)+E-GSM(900)+DCS(1800)+PCS(1900)");

  // Empty the incoming buffer
  while (Serial.available()) {
    Serial.read();
  }

  // Wait for an answer, just look at the first character
  while (!Serial.available());
  char c = Serial.read();
  if (c == '1') {
    newBand = GSM_MODE_EGSM;
  } else if (c == '2') {
    newBand = GSM_MODE_DCS;
  } else if (c == '3') {
    newBand = GSM_MODE_PCS;
  } else if (c == '4') {
    newBand = GSM_MODE_EGSM_DCS;
  } else if (c == '5') {
    newBand = GSM_MODE_GSM850_PCS;
  } else if (c == '6') {
    newBand = GSM_MODE_GSM850_EGSM_DCS_PCS;
  } else {
    newBand = "GSM_MODE_UNDEFINED";
  }
  return newBand;
}

See Also




Last revision 2015/08/17 by SM

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