Sim 900 difficulty

Other Hardware 3rd Party Boards
1

Hello I am following this tutorial.

I hooked up everything perfectly and am now trying to figure out the phone number on the card because I need to activate it.

I use the following code to access my number from my sin.

#include <SoftwareSerial.h>

//Create software serial object to communicate with SIM900
SoftwareSerial mySerial(7, 8); //SIM900 Tx & Rx is connected to Arduino #7 & #8

void setup()
{
  //Begin serial communication with Arduino and Arduino IDE (Serial Monitor)
  Serial.begin(9600);
  
  //Begin serial communication with Arduino and SIM900
  mySerial.begin(9600);

  Serial.println("Initializing...");
  delay(1000);

  mySerial.println("AT"); //Handshaking with SIM900
  updateSerial();
  mySerial.println("AT+CSQ"); //Signal quality test, value range is 0-31 , 31 is the best
  updateSerial();
  mySerial.println("AT+CCID"); //Read SIM information to confirm whether the SIM is plugged
  updateSerial();
  mySerial.println("AT+CREG?"); //Check whether it has registered in the network
  updateSerial();
}

void loop()
{
  updateSerial();
}

void updateSerial()
{
  delay(500);
  while (Serial.available()) 
  {
    mySerial.write(Serial.read());//Forward what Serial received to Software Serial Port
  }
  while(mySerial.available()) 
  {
    Serial.write(mySerial.read());//Forward what Software Serial received to Serial Port
  }
}

I am getting no response back. Can I send commands to my sim 900 if the card is not activated? Thanks bye.

2

Have you tried putting that SIM into a phone ?
Where did you get the SIM from? They usually give you the associated phone number and you might have a locked sim so need to know the pin code

Describe how perfectly you connected and powered everything… that matters. A hand drawn schéma of how things are (not should be) goes a long way.. give a link to your module, which arduino are you using?…

Post the full code. Don’t post snippets (Snippets R Us!)

How is your serial console setup

3

The SIM900 should respond in some way to those commands, even without a SIM installed or if the SIM is not recognised on the network.

Check that the TX/RX lines are correct -- maybe just try the other way around.
I assume you have switch the module on? Most SIM900 units do not switch on just because power is supplied -- you have to press the power switch or toggle the power control signal.

4

This topic was automatically closed 120 days after the last reply. New replies are no longer allowed.