interface with GSM SIM 300 with ARDUINO UNO R3

I’m unable to send message through gsm modem from arduino uno. My devices and connections are in the pics. I’ve used RX and TX pins of Aruino. I’ve tested the modem by hyperterminal in the pc and received acknowledgement also. But when I connect it to arduino, unable to send message.
my code is:
void setup()
{
Serial.begin(9600); // the GPRS baud rate
delay(2000);
Serial.println(“AT”);
delay(2000);
Serial.println(“AT+CSMP=17,167,0,0”);
delay(2000);
}
void loop()
{
Serial.println(“AT+CMGF=1”); // set the SMS mode to text
delay(2000);
Serial.print(“AT+CMGS=”);
Serial.print(34,BYTE); //ASCII of “
Serial.print("+91XXXXXXXX");
Serial.println(34,BYTE);
delay(2000);
Serial.println(“hello”); //this is the message to be sent
delay(2000);
Serial.println(26,BYTE); //Ascii code of ctrl+z to send the message
delay(2000);
while(1);
}

First thing, check your Arduino board is sending the message.
(1. Disconnect TTL/Serial adapter from Arduino
2. Upload a blank program - void setup(){}
void loop(){}
3. Make a short circuit between Tx and Rx on Arduino
4. Open whatever serial monitor you are using and select the proper port for Arduino and type commands.
5. If you see on display what you type in than Arduino is OK.)

Second step check the Arduino+TTL/Serial adapter
(1. Determine what pins are used on D-Sub conector from TTL/Serial adapter and make short circuit Tx and Rx
2. Open whatever serial monitor you are using and type commands.
3. If you see on display what you type in than Arduino+TTL/Serial adapter is OK.)

Thirdly, your program is not OK, modify the program in order to use other pins for communication with Sim300 and maintain Rx, Tx standard pins form Arduin for connection with your PC -monitoring the status.

Good luck!

@GOGU : Thanks for ur reply. I checked both Arduino and TTL/Serial adapter are OK. And have edited the code in order to change the pins as follows. But stil unable to send message. :~ I doubt the serial communication between TTL/Serial adapter and GSM modem is not taking place.

#include <SoftwareSerial.h>
SoftwareSerial mySerial(10,11);
void setup()
{
mySerial.begin(9600); // the GPRS baud rate
delay(2000);
mySerial.println(“AT”);
delay(2000);
mySerial.println(“AT+CSMP=17,167,0,0”);
delay(2000);
}
void loop()
{
mySerial.println(“AT+CMGF=1”); // set the SMS mode to text
delay(2500);
mySerial.write(“AT+CMGS=”);
mySerial.write(34); //ASCII of “
mySerial.write("+91xxxxxxxxxx");
mySerial.write(34);
mySerial.write(13);
mySerial.write(10);
delay(2500);
mySerial.println(“hello”); //this is the message to be sent
delay(2500);
mySerial.write(26);
mySerial.write(13);
mySerial.write(10);//Ascii code of ctrl+z to send the message
delay(2500);
while(1);
}

Make the connections between Arduino Uno and Sim300 at TTL level. Use Arduino uno as USB/serial TTL converter. Connect Tx and Rx pins from Arduino to Sim300 TTL pins accordingly. Initiate AT commands using your serial monitoring program and see what you receive.

Good luck!

Hey! I am working on the same project presently. I have a question. Is it necessary to use a hyperterminal and TTL converter seperately? Can I use just the pins marked 2 & 3 on the the GSM board instead?

Thanks!

Hi, I want to use the "receive sms" or "receive call" feature using Arduino MEGA 2560 and SIM300 devices but am unable to code it.

I am currently doing a project and my project requires to use the "receive sms" or "receive call" feature in such a way that whenever I will send a "sms" or a "call" to the modem it will detect it and automatically reply to the "sms" or "call" by sending the water level.

I am able to use the "send call" and "send sms" features using the "AT" commands by using the above devices but now in order to make it a two way communication I need to implement the above.

Hence anyone with any idea please reply how can I implement the "receive call" or "receive sms" features.

Its really urgent!!!!!!!Please reply soon