GSMToolsTestModem

Read the IMEI of your modem and print it in the Serial Monitor.

LAST REVISION: 12/07/2022, 02:23 PM

GSM Test Modem

This sketch tests the modem on the GSM shield to see if it is working correctly. You do not need a SIM card for this example.

Hardware Required

Arduino Board
Arduino + Telefonica GSM/GPRS Shield

Circuit

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

Code

First, import the GSM library

#include <GSM.h>

Create an instance of the GSMModem class:

GSMModem modem;

Create a variable to hold the IMEI number of the modem

1String IMEI = "";

setup

, open a serial connection to the computer. After opening the connection, send a message indicating the sketch has started.

1void setup(){
2
3  Serial.begin(9600);
4
5  Serial.print("Starting modem test...");

Call

modem.begin()

to start the modem. Send a status message depending on the outcome, and end

setup()

1if(modem.begin())
2
3    Serial.println("modem.begin() succeeded");
4
5  else
6
7    Serial.println("ERROR, no modem answer.");
8}

Inside

loop

, use

modem.getIMEI()

to return the IMEI number of the modem. This number is unique to your GSM shield.

1void loop()
2{
3
4  // get modem IMEI
5
6  Serial.print("Checking IMEI...");
7
8  IMEI = modem.getIMEI();

If there is a valid response from

getIMEI()

, print it to the serial monitor and reset the modem with

modem.begin()

1if(IMEI != NULL)
2
3  {
4
5    // show IMEI in serial monitor
6
7    Serial.println("Modem's IMEI: " + IMEI);
8
9    // reset modem to check booting:
10
11    Serial.print("Resetting modem...");
12
13    modem.begin();

Once reset, check the IMEI again. If it is a valid return again, the modem is functioning as expected.

1if(modem.getIMEI() != NULL)
2
3    {
4
5      Serial.println("Modem is functioning properly");
6
7    }

If, after resetting the modem, there is not a valid return from

getIMEI()

, report an error

1else
2
3    {
4
5      Serial.println("Error: getIMEI() failed after modem.begin()");
6
7    }

If you never received an IMEI after starting the sketch, report it, and end the program.

1}
2
3  else
4
5  {
6
7    Serial.println("Error: Could not get IMEI");
8
9  }
10
11  // do nothing:
12
13  while(true);
14}

Once your code is uploaded, open the serial monitor. You should see the HTML of http://arduino.cc print out on screen when it is received.

Complete Sketch

The complete sketch is below.

1/*
2
3 This example tests to see if the modem of the
4
5 GSM shield is working correctly. You do not need
6
7 a SIM card for this example.
8
9 Circuit:
10
11 * GSM shield attached
12
13 Created 12 Jun 2012
14
15 by David del Peral
16
17 modified 21 Nov 2012
18
19 by Tom Igoe
20
21 http://www.arduino.cc/en/Tutorial/GSMToolsTestModem
22
23 This sample code is part of the public domain
24
25 */
26
27// libraries
28#include <GSM.h>
29
30// modem verification object
31
32GSMModem modem;
33
34// IMEI variable
35
36String IMEI = "";
37
38void setup() {
39
40  // initialize serial communications and wait for port to open:
41
42  Serial.begin(9600);
43
44  while (!Serial) {
45
46    ; // wait for serial port to connect. Needed for Leonardo only
47
48  }
49
50  // start modem test (reset and check response)
51
52  Serial.print("Starting modem test...");
53
54  if (modem.begin()) {
55
56    Serial.println("modem.begin() succeeded");
57
58  } else {
59
60    Serial.println("ERROR, no modem answer.");
61
62  }
63}
64
65void loop() {
66
67  // get modem IMEI
68
69  Serial.print("Checking IMEI...");
70
71  IMEI = modem.getIMEI();
72
73  // check IMEI response
74
75  if (IMEI != NULL) {
76
77    // show IMEI in serial monitor
78
79    Serial.println("Modem's IMEI: " + IMEI);
80
81    // reset modem to check booting:
82
83    Serial.print("Resetting modem...");
84
85    modem.begin();
86
87    // get and check IMEI one more time
88
89    if (modem.getIMEI() != NULL) {
90
91      Serial.println("Modem is functioning properly");
92
93    } else {
94
95      Serial.println("Error: getIMEI() failed after modem.begin()");
96
97    }
98
99  } else {
100
101    Serial.println("Error: Could not get IMEI");
102
103  }
104
105  // do nothing:
106
107  while (true);
108}

Last revision 2018/08/23 by SM

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