arduino gsm shield error 0

Question

I have been trying to send a simple message using an arduino microcontroller and a gsm shield but it keeps getting an error 0.

Here is the code:

int8_t answer;
int onModulePin= 2;
char aux_string[20];
char phone_number[]="*********";

void setup(){

    pinMode(onModulePin, OUTPUT);
    Serial.begin(115200);    

    Serial.println("Starting...");
    power_on();

    delay(3000);

    // sets the PIN code
    sendATcommand("AT+CPIN=****", "OK", 2000);

    delay(3000);

    Serial.println("Connecting to the network...");

    while( (sendATcommand("AT+CREG?", "+CREG: 0,1", 500) || sendATcommand("AT+CREG?", "+CREG: 0,5", 500)) == 0 );

    Serial.print("Setting SMS mode...");
    sendATcommand("AT+CMGF=1", "OK", 1000);    // sets the SMS mode to text
    Serial.println("Sending SMS");

    sprintf(aux_string,"AT+CMGS=\"%s\"", phone_number);
    answer = sendATcommand(aux_string, ">", 2000);    // send the SMS number
    if (answer == 1)
    {
        Serial.println("Test-Arduino-Hello World");
        Serial.write(0x1A);
        answer = sendATcommand("", "OK", 20000);
        if (answer == 1)
        {
            Serial.print("Sent ");    
        }
        else
        {
            Serial.print("error ");
        }
    }
    else
    {
        Serial.print("error ");
        Serial.println(answer, DEC);
    }

}


void loop(){

}

void power_on(){

    uint8_t answer=0;

    // checks if the module is started
    answer = sendATcommand("AT", "OK", 2000);
    if (answer == 0)
    {
        // power on pulse
        digitalWrite(onModulePin,HIGH);
        delay(3000);
        digitalWrite(onModulePin,LOW);

        // waits for an answer from the module
        while(answer == 0){     // Send AT every two seconds and wait for the answer
            answer = sendATcommand("AT", "OK", 2000);    
        }
    }

}

int8_t sendATcommand(char* ATcommand, char* expected_answer, unsigned int timeout){

    uint8_t x=0,  answer=0;
    char response[100];
    unsigned long previous;

    memset(response, '\0', 100);    // Initialice the string

    delay(100);

    while( Serial.available() > 0) Serial.read();    // Clean the input buffer

    Serial.println(ATcommand);    // Send the AT command 


    x = 0;
    previous = millis();

    // this loop waits for the answer
    do{
        if(Serial.available() != 0){    // if there are data in the UART input buffer, reads it and checks for the asnwer
            response[x] = Serial.read();
            x++;
            if (strstr(response, expected_answer) != NULL)    // check if the desired answer is in the response of the module
            {
                answer = 1;
            }
        }
    }while((answer == 0) && ((millis() - previous) < timeout));    // Waits for the asnwer with time out

    return answer;
}

Prakash Kumar Prakash Kumar · Accepted Answer · 2015-10-09T16:34:50

char phone_number[]="*********";

In the above code, replace ********* with 9xxxxyyyyy (Sim Number/ Mobile Number)

char phone_number[]="*********";

Then start the Serial Monitor with the mentioned baud rate (115200 as in the above code)

arduino gsm shield error 0

1 Answers