Arduino GSM receiving text and then storing value as a variable in code

Question

I am using an Arduino Mega board with a SIM900 GSM.

My goal is to be able to text the GSM with a value of two digits (ex: 79) and then store that value as a variable in the code. I know how to set up the Mega and the GSM in terms of wiring and initialization of ports, but how would I write a short function to test the incoming values and save them to a variable?

I thought about testing each bit individually, storing each one as a separate variable, and then adding them for the total. For example, if the GSM received "#79" as a text I stored the value 7 as an integer variable named One and the value 9 as an integer variable named Two. Then I did

Total = (One*10)+Two.

I am posting my code below that used this method, although it has not proved to be useful. If anyone has any suggestions I would greatly appreciate it.

#include <SoftwareSerial.h>   //GSM Library 

int Max_temp;                  
float threshold;                   

SoftwareSerial SIM900(18, 19);                
String destinationNumber = "+17186578989";  
String outMessage1 = "Please enter the maximum desired room temp";  
char inchar; // Will hold the incoming character from the GSM shield when user texts it 
int M_one;
int M_zero;
void GSM_SEND_MAX();            
void GSM_RECEIVE_MAX();       

void setup() 
{
   Serial.begin(9600); 

//GSM setup:                       
  Serial1.begin(19200);  // wake up the GSM shield
  delay(20000); // give time to log on to network.
  Serial1.print("AT+CMGF=1\r"); // set SMS mode to text
  delay(100);
  Serial1.print("AT+CNMI=2,2,0,0,0\r"); // blurt out contents of new SMS upon receipt to the GSM shield's serial out
  delay(100);
}// end void set up() 




void loop() 
{
  GSM_SEND_MAX();
  GSM_RECEIVE_MAX();
}// end void loop ()

/////Functions 
void GSM_SEND_MAX()       
{
  Serial.println("sending text");    
  Serial1.begin(19200); 
  delay(20000); // give time to log on to network.
  Serial1.print("AT+CMGF=1\r");
  delay(1000);
  Serial1.println("AT + CMGS = \"" + destinationNumber +"\"");
  delay(1000);
  Serial1.print(outMessage1);
  delay(1000);
  Serial1.write((char)26); //ctrl+z
  delay(1000);
  Serial.println("send text");
}//end GSM_SEND_MAX funtion 

void GSM_RECEIVE_MAX()        
{
  //If a character comes in from the cellular module...
 while (Serial1.peek() != '#' )   
   {
    inchar=Serial1.read();      
    Serial.print("bad char ");   
    Serial.println(inchar);     
    delay(500);
   }// end while #1 

 inchar=Serial1.peek();            
 Serial.println("out of loop 1");   
 Serial.println(inchar);           

 while (Serial1.available() != 0) //While #2 reads incoming char 
 {
    Serial.println("in loop 2");  
    inchar=Serial1.read();       

if (inchar=='#')             
  {
  delay(10);
  Serial.print("got #");    
  M_one=Serial1.read();    

  if (M_one >= 0 )
  {
  delay(10);
  Serial.println();
  Serial.print("got M_one");   
  Serial.print(M_one);
  M_zero=Serial1.read();   

      if (M_zero >= 0)
      {
          Serial.println();
          Serial.print("got M_zero");  
          Serial.print(M_zero); 

       }//end m_zero 

  }//end m_one 
  Max_temp = (M_one *10) + M_zero; 

  Serial.println();
  Serial.print("Max_temp=");
  Serial.print(Max_temp); 

  } //end if (inchar==#)

 }// end while #2 loop  
}//end GSM_RECEIVE_MAX function

Arduino GSM receiving text and then storing value as a variable in code

0 Answers0