Problem while writing sketch for GSM module sim800

Question

I wanted to my GSM to recieve SMSs. I have written a sketch for it. But while verifying the sketch an error pops out in this part:

if (sms.available()) { sms.remoteNumber(senderNnumber, 20); if (senderNumber == "09432167015") { c = sms.read(); if (c == "yes") { alarm_police(); } } }

The error message:

Arduino: 1.6.5 (Windows 8.1), Board: "Arduino/Genuino Uno"

GuardDog_v2.5.ino: In function 'void loop()': GuardDog_v2.5:201: error: 'senderNnumber' was not declared in this scope GuardDog_v2.5:204: error: ISO C++ forbids comparison between pointer and>integer [-fpermissive] 'senderNnumber' was not declared in this scope

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I have checked the receiving sms example and have written the sketch according to the example.I need help regarding this error and how to fix it

• SoreDakeNoKoto: You have a scope problem and you are comparing a pointer to an integer. Show us the rest of your sketch and provide a link to the library u're using
• HDatta: The sketch is a bit too big and contains parts which are not related to GSM. Should I show the complete sketch? BTW the library I used is the default GSM library which is present in the IDE.

Answer 1

You misspelled the variable senderNumber. Correct it. Also you aren't reading the SMS properly or comparing the phone numbers properly. Your code should be like this (using the examples):

#define MAX_MSG 50
char senderNumber[20];
char sms_buf[MAX_MSG]; // a buffer for your sms, max len = 50
if (sms.available()) { // this part should be in loop()
 sms.remoteNumber(senderNumber, 20);
 if (strcmp(senderNumber, "09432167015") == 0) { // compare numbers
 while (sms.available() == 0); // wait for a char
 char i = 0;
 while (i < MAX_MSG - 1){ // till max len is reached; 1 byte for null
 c = sms.read();
 if (c == '0円') // assuming the modem terminates sms with null
 break;
 sms_buf[i++] = c; // write char to the buffer
 while (sms.available() == 0); //wait for a char
 }
 sms_buf[i] = 0; // terminate the string, just in case
 if (strstr(sms_buf, "yes") != NULL) // look for 'yes' in buffer
 alarm_police();
 }
}

• HDatta: is MAX_MSG an int
• SoreDakeNoKoto: It can be a char or int; just edited it
• HDatta: during the upload an error for char sms_buf[MAX_MSG]; pops up: array bound is not an integer constant before ']' token.
• SoreDakeNoKoto: Change MAX_MSG to int and try again
• HDatta: I had used int for MAX_MSG it doesn't work for both char and int