GSM PIN Management

Manage the PIN number of your SIM card (changing or removing it).

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 board
image of the Arduino GSM Shield on top of an Arduino 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.

1String user_input = "";
2
3boolean auth = false;
4
5String oktext = "OK";
6
7String 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.

1void setup(){
2
3 Serial.begin(9600);
4
5 Serial.println("Change PIN example\n");
6
7 PINManager.begin();

Check to see if the SIM is locked with a PIN

1while(!auth){
2
3 int pin_query = PINManager.isPIN();
4
5 if(pin_query == 1)
6
7 {

If locked, ask for the PIN via the serial monitor. You'll use a custom function named

readSerial()
to parse the information.

1Serial.print("Enter PIN code: ");
2
3 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.

1if(PINManager.checkPIN(user_input) == 0)
2
3 {
4
5 auth = true;
6
7 PINManager.setPINUsed(true);
8
9 Serial.println(oktext);
10
11 }
12
13 else
14
15 {
16
17 Serial.println("Incorrect PIN. Remember that you have 3 opportunities.");
18
19 }
20
21 }

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

1else if(pin_query == -1)
2
3 {
4
5 Serial.println("PIN locked. Enter PUK code: ");
6
7 String puk = readSerial();
8
9 Serial.print("Now, enter a new PIN code: ");
10
11 user_input = readSerial();
12
13 if(PINManager.checkPUK(puk, user_input) == 0)
14
15 {
16
17 auth = true;
18
19 PINManager.setPINUsed(true);
20
21 Serial.println(oktext);
22
23 }
24
25 else
26
27 {
28
29 Serial.println("Incorrect PUK or invalid new PIN. Try again!.");
30
31 }
32
33 }

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

1else if(pin_query == -2)
2
3 {
4
5 Serial.println("PIN & PUK locked. Use PIN2/PUK2 in a mobile phone.");
6
7 while(true);
8
9 }

If there's no PIN number, set the

auth
flag to
true

1else
2
3 {
4
5 // SIM does not requires authetication
6
7 Serial.println("No pin necessary.");
8
9 auth = true;
10
11 }
12
13 }

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

1Serial.print("Checking register in GSM network...");
2
3 if(PINManager.checkReg() == 0)
4
5 Serial.println(oktext);
6
7 else if(PINManager.checkReg() == 1)
8
9 Serial.println("ROAMING " + oktext);
10
11 else
12
13 {
14
15 Serial.println(errortext);
16
17 while(true);
18
19 }
20}

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

String
.

1String readSerial()
2{

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

1String text = "";
2
3 while(1)
4
5 {
6
7 while (Serial.available() > 0)
8
9 {
10
11 char inChar = Serial.read();
12
13 if (inChar == '\n')
14
15 {
16
17 return text;
18
19 }
20
21 if(inChar!='\r')
22
23 text += inChar;
24
25 }
26
27 }
28}

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

1void loop()
2{
3
4 Serial.println("Choose an option:\n1 - On/Off PIN.");
5
6 if(PINManager.getPINUsed())
7
8 Serial.println("2 - Change PIN.");
9
10 String user_op = readSerial();
11
12 if(user_op == "1")
13
14 {
15
16 Serial.println("Enter your PIN code:");
17
18 user_input = readSerial();
19
20 PINManager.switchPIN(user_input);
21
22 }
23
24 else if(user_op == "2" & PINManager.getPINUsed())
25
26 {
27
28 Serial.println("Enter your actual PIN code:");
29
30 String oldPIN = readSerial();
31
32 Serial.println("Now, enter your new PIN code:");
33
34 String newPIN = readSerial();
35
36 PINManager.changePIN(oldPIN, newPIN);
37
38 }
39
40 else
41
42 {
43
44 Serial.println("Incorrect option. Try again!.");
45
46 }
47
48 delay(1000);
49}

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

Complete Sketch

The complete sketch is below.

1/*
2
3 Band Management
4
5 This sketch, for the Arduino GSM shield, checks the band
6
7 currently configured in the modem and allows you to change
8
9 it.
10
11 Please check http://www.worldtimezone.com/gsm.html
12
13 Usual configurations:
14
15 Europe, Africa, Middle East: E-GSM(900)+DCS(1800)
16
17 USA, Canada, South America: GSM(850)+PCS(1900)
18
19 Mexico: PCS(1900)
20
21 Brazil: GSM(850)+E-GSM(900)+DCS(1800)+PCS(1900)
22
23 Circuit:
24
25 * GSM shield
26
27 created 12 June 2012
28
29 by Javier Zorzano, Scott Fitzgerald
30
31 This example is in the public domain.
32
33 */
34
35// libraries
36#include <GSM.h>
37
38// initialize the library instance
39
40GSMBand band;
41
42void setup() {
43
44 // initialize serial communications and wait for port to open:
45
46 Serial.begin(9600);
47
48 while (!Serial) {
49
50 ; // wait for serial port to connect. Needed for Leonardo only
51
52 }
53
54 // Beginning the band manager restarts the modem
55
56 Serial.println("Restarting modem...");
57
58 band.begin();
59
60 Serial.println("Modem restarted.");
61
62};
63
64void loop() {
65
66 // Get current band
67
68 String bandName = band.getBand(); // Get and print band name
69
70 Serial.print("Current band:");
71
72 Serial.println(bandName);
73
74 Serial.println("Want to change the band you're on?");
75
76 String newBandName;
77
78 newBandName = askUser();
79
80 // Tell the user what we are about to do...
81
82 Serial.print("\nConfiguring band ");
83
84 Serial.println(newBandName);
85
86 // Change the band
87
88 bool operationSuccess;
89
90 operationSuccess = band.setBand(newBandName);
91
92 // Tell the user if the operation was OK
93
94 if (operationSuccess) {
95
96 Serial.println("Success");
97
98 } else {
99
100 Serial.println("Error while changing band");
101
102 }
103
104 if (operationSuccess) {
105
106 while (true);
107
108 }
109}
110
111// This function offers the user different options
112// through the Serial interface
113// The user selects one
114
115String askUser() {
116
117 String newBand;
118
119 Serial.println("Select band:");
120
121 // Print the different options
122
123 Serial.println("1 : E-GSM(900)");
124
125 Serial.println("2 : DCS(1800)");
126
127 Serial.println("3 : PCS(1900)");
128
129 Serial.println("4 : E-GSM(900)+DCS(1800) ex: Europe");
130
131 Serial.println("5 : GSM(850)+PCS(1900) Ex: USA, South Am.");
132
133 Serial.println("6 : GSM(850)+E-GSM(900)+DCS(1800)+PCS(1900)");
134
135 // Empty the incoming buffer
136
137 while (Serial.available()) {
138
139 Serial.read();
140
141 }
142
143 // Wait for an answer, just look at the first character
144
145 while (!Serial.available());
146
147 char c = Serial.read();
148
149 if (c == '1') {
150
151 newBand = GSM_MODE_EGSM;
152
153 } else if (c == '2') {
154
155 newBand = GSM_MODE_DCS;
156
157 } else if (c == '3') {
158
159 newBand = GSM_MODE_PCS;
160
161 } else if (c == '4') {
162
163 newBand = GSM_MODE_EGSM_DCS;
164
165 } else if (c == '5') {
166
167 newBand = GSM_MODE_GSM850_PCS;
168
169 } else if (c == '6') {
170
171 newBand = GSM_MODE_GSM850_EGSM_DCS_PCS;
172
173 } else {
174
175 newBand = "GSM_MODE_UNDEFINED";
176
177 }
178
179 return newBand;
180}

Last revision 2018/08/23 by SM

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