Arduino UNO & SIM900 -AT communicaton problem

Projects Networking, Protocols, and Devices
47

Can someone help me? [Sure - code tags added my moderator] This is my code.

#include <LiquidCrystal.h>
#include "SIM900.h"
#include "sms.h"
#include <SoftwareSerial.h>
//#include <sms.h>
#include <PString.h>
SMSGSM sms;
boolean started = false;
char buffer[160];
char smsbuffer[160];
char n[20];
//LiquidCrystal lcd(4,2,3,7,8,9);
int buttonState;
int lastButtonState = LOW;
long lastDebounceTime = 0;
long debounceDelay = 50;
boolean st = false;
int buzzer = 12;

void setup() {


 //lcd.begin(16, 2);
 Serial.begin(9600);
 if (gsm.begin(2400))
 {
   started = true;
 }
 if (started)
 {
   delsms();
 }
 sms.SendSMS("+60142646978" , "Gas Sensor and GSM module activated");


}

void loop() {

 //lcd.setCursor(0, 0);

 //lcd.print("Detektor Gas SMS");
 int val = analogRead(A0);
 val = map(val, 0, 1023, 0, 100);
 //lcd.setCursor(0,1);
 //lcd.print("Kadar: ");
 //lcd.print(val);
 //lcd.print("%   ");

 //code using sensor detection
 if (val > 10) {
   tone(buzzer,800,500);
 delay(1000);
   st = true;
 }
 else st = false;

 if (st != lastButtonState) {
   lastDebounceTime = millis();
 }


 if ((millis() - lastDebounceTime) > debounceDelay) {

   if (st != buttonState) {
     buttonState = st;


     if (buttonState == HIGH) {
       PString str(buffer, sizeof(buffer));
       str.begin();
       str.print("Gas Detected! Gas leakage at ");
       str.print(val);
       str.print("%");
       //String a=str;
       sms.SendSMS("+60142646978", buffer);
     }
   }
 }

 //code using sms lapor.
 lastButtonState = st;
 int pos = 0;
 if (started)
 {
   pos = sms.IsSMSPresent(SMS_ALL);
   if (pos)
   {
     sms.GetSMS(pos, n, smsbuffer, 100);
     delay(2000);
     if (!strcmp(smsbuffer, "lapor"))
     {
       PString str(buffer, sizeof(buffer));
       str.begin();
       str.print("Rate of gas leakage currently at ");
       str.print(val);
       str.print("%");
       //String a=str;
       sms.SendSMS("+60142646978", buffer);
     }
     delsms();
   }
 }
}

//delete sms yang dihantar
void delsms()
{
 for (int i = 0; i < 10; i++)
 {
   int pos = sms.IsSMSPresent(SMS_ALL);
   if (pos != 0)
   {
     if (sms.DeleteSMS(pos) == 1) {} else {}
   }
 }
}

I'm using arduino uno, sim900 module, mq2 gas sensor and buzzer to create a gas sensor detector based on sms.
I have to 2 option :

  1. The mq2 gas sensor detects and send the result via sms to the number set in the code.
  2. We can send a specific string to know the surrounding gas percentage and send the result to the specific number set in the code.

But I want to change the second option to be auto reply to any incoming number. What should I do?