I have an Arduino Uno that is interfaced with GSM. I wrote a code which makes the GSM send SMS if it receives an SMS with letter ('s'). The problem is when the GSM received letter 's' it keeps sending multiple SMSs rather than one.
Anyone can solve this problem ??
Here is the code that I wrote it.
use the code tags and post your code, not the image
this is the code
#include <SoftwareSerial.h>
SoftwareSerial mySerial(7, 8); // Rx,Tx
String textMessage;
String message;
void setup()
{
mySerial.begin(9600); // Setting the baud rate of GSM Module
Serial.begin(9600); // Setting the baud rate of Serial Monitor (Arduino)
delay(20000); // it should be 20000 to connect gsm to network
Serial.print("SIM900 ready...");
delay(1000);
// AT command to set SIM900 to SMS mode
mySerial.print("AT+CMGF=1\r");
delay(1000);
// Set module to send SMS data to serial out upon receipt
mySerial.print("AT+CNMI=2,2,0,0,0\r");
delay(1000);
}
void loop()
{
if(mySerial.available()>0){
textMessage = mySerial.readString();
Serial.print(textMessage);
delay(1000);
if(textMessage.indexOf("s")>=0){
message= "led is on";
SendMessage(message);
delay(1000);
textMessage = "";
}}}
void SendMessage(String message)
{
mySerial.println("AT+CMGF=1"); //Sets the GSM Module in Text Mode
delay(1000); // Delay of 1000 milli seconds or 1 second
mySerial.println("AT+CMGS="+966554942736"\r"); // Replace x with mobile number
delay(2000);
mySerial.println(message);// The SMS text you want to send
delay(2000);
mySerial.println((char)26);// ASCII code of CTRL+Z
delay(5000);
}