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GSM Sim900A Modem

GSM/GPRS Modem-RS232 is built with Dual-Band GSM/GPRS engine- SIM900A works on frequencies 900/ 1800 MHz. The Modem is coming with RS232 interface, which allows you connect PC as well as a microcontroller with RS232 Chip(MAX232). The baud rate is configurable from 9600-115200 through AT command. The GSM/GPRS Modem is having internal TCP/IP stack to enable you to connect with internet via GPRS. It is suitable for SMS, Voice as well as DATA transfer application in M2M interface. The onboard Regulated Power supply allows you to connect wide range unregulated power supply. Using this modem, you can make audio calls, SMS, Read SMS, attend the incoming calls and internet etc through simple AT commands.

Order Code : RDL/GSM/13/002/V1.0

SIM900A Module is Outdated and updated version of the module given below link.

GSM GPRS SIM800C

Availability: Out of stock

₹1,380.00
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Questions:

Posted by micheal, Saturday, 22 August 2015 on product GSM Sim900A Modem
  • 0
    vote
    A:

    Dear Customer

    Please find the code below, also the same code can be used to on/off the pump.


    int8_t answer;
    int x;

    char SMS[200];

    void setup(){

     
        Serial.begin(9600);  

        pinMode(8, OUTPUT);
                digitalWrite(8, LOW);
        power_on();
            // turn the LED on (HIGH is the voltage level)
      delay(1000);              // wait for a second


     Serial.println("Network...");
         while( (sendATcommand("AT+CREG?", "+CREG: 0,1", 500) ||
                sendATcommand("AT+CREG?", "+CREG: 0,5", 500)) == 0 );
                
    delay(300);
    //Signal();
     
        
        Serial.println("Setting SMS mode...");
        sendATcommand("AT+CMGF=1", "OK", 1000);    // sets the SMS mode to text
        delay(300);
         
      sendATcommand("AT+CMGD=1", "OK", 1000);
      Serial.println("SEND SMS... TO READ");
    }


    void loop(){
       answer = sendATcommand("AT+CMGR=1", "+CMGR:", 2000);    // reads the first SMS
        if (answer == 1)
      {x=0;
            memset(SMS, '\0', 100);
            answer = 0;
            while(Serial.available() == 0);
            // this loop reads the data of the SMS
            do{
                // if there are data in the UART input buffer, reads it and checks for the asnwer
                if(Serial.available() > 0){
               
              
                    SMS[x] = Serial.read();
                    x++;
                    // check if the desired answer (OK) is in the response of the module
                 
                    
                     if (strstr(SMS, "PUMP ON") != NULL)    
                    {
                      digitalWrite(8, HIGH);
                         answer = 1;
                    }
                    
                      if (strstr(SMS, "PUMP OFF") != NULL)    
                    {
                       digitalWrite(8, LOW);
                          answer = 1;
                    }
                       if (strstr(SMS, "OK") != NULL)    
                    {
                        answer = 1;
                    }
                    
                }
            }while(answer == 0);    // Waits for the asnwer with time out
            
            
            SMS[x] = '\0';
                   Serial.print(SMS);   
              delay(200);
            sendATcommand("AT+CMGD=1", "OK", 1000);   
                     delay(100);
                     sendATcommand("AT+CMGD=1,4", "OK", 1000);
                           delay(200);
                    

        }
       
        delay(1000);
     
    }

    void power_on(){

        uint8_t answer=0;
        
        // checks if the module is started
        answer = sendATcommand("AT", "OK", 2000);
        if (answer == 0)
        {
            
        
            // 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 there are data in the UART input buffer, reads it and checks for the asnwer
            if(Serial.available() != 0){    
                response[x] = Serial.read();
                x++;
                // check if the desired answer is in the response of the module
                if (strstr(response, expected_answer) != NULL)    
                {
                    answer = 1;
                }
            }
            // Waits for the asnwer with time out
        }while((answer == 0) && ((millis() - previous) < timeout));    

        return answer;
    }


    void Signal()
    {
    answer = sendATcommand("AT+CSQ", "+CSQ", 2000);    // reads the first SMS
         
        if (answer == 1)
        {x=0;
            memset(SMS, '\0', 300);
            answer = 0;
            while(Serial.available() == 0);
            // this loop reads the data of the SMS
            do{
                // if there are data in the UART input buffer, reads it and checks for the asnwer
                if(Serial.available() > 0){    
                    SMS[x] = Serial.read();
                    x++;
           
                    if (strstr(SMS, "OK") != NULL)    
                    {
                        answer = 1;
                    }
                }
            }while(answer == 0);    // Waits for the asnwer with time out
            
            
            SMS[x] = '\0';
             Serial.println(SMS);
             
                   delay(100);
        }
        
    }

    Posted by Rashmi P on Saturday, 22 August 2015
Posted by chiradeep, Wednesday, 15 July 2015 on product GSM Sim900A Modem
  • 0
    vote
    A:

    Dear Sir,

    HTTPS is not supported by sim900a modems. It supports FTP/HTTP.

    Posted by Dipti Divakar on Wednesday, 15 July 2015
Posted by vinod, Friday, 13 March 2015 on product GSM Sim900A Modem
  • 0
    vote
    A:

    Please go through the below Image to know how to interface with Ardiuno ,



    Posted by Dipti Divakar on Friday, 13 March 2015

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