central_unit.ino

#include <SoftwareSerial.h>

SoftwareSerial mySerial(3, 2);

//f for full(green) led, e for empty(red) led
const int tank_1f = 3; // tank_1f is for tank 1 full led
const int tank_1e = 2; // tank_1e is for tank 1 empty led
const int tank_2f = 5;
const int tank_2e = 4;

//uncomment below lines to add more leds and EDIT respective pin numbers

//const int tank_3f = ;
//const int tank_3e = ;
//const int tank_4f = ;
//const int tank_4e = ;
//const int tank_5f = ;
//const int tank_5e = ;
//const int tank_6f = ;
//const int tank_6e = ;
//const int tank_7f = ;
//const int tank_7e = ;

const int buzzer = 6; //buzzer to arduino pin


String inputString = "";         // a string to hold incoming data
boolean stringComplete = false;  // whether the string is complete
String incomingString ="";

int startIndex = 0;
int endIndex = 0;


void setup() {
  // put your setup code here, to run once:
  // initialize the digital pin as an output.
  pinMode(tank_1f, OUTPUT);
  pinMode(tank_1e, OUTPUT);
  pinMode(tank_2f, OUTPUT);
  pinMode(tank_2e, OUTPUT);
  
  //uncomment below lines for more leds
   
//  pinMode(tank_3f, OUTPUT);
//  pinMode(tank_3e, OUTPUT);
//  pinMode(tank_4f, OUTPUT);
//  pinMode(tank_4e, OUTPUT);
//  pinMode(tank_5f, OUTPUT);
//  pinMode(tank_5e, OUTPUT);
//  pinMode(tank_6f, OUTPUT);
//  pinMode(tank_6e, OUTPUT);
//  pinMode(tank_7f, OUTPUT);
//  pinMode(tank_7e, OUTPUT);

//pinMode(buzzer, OUTPUT); // Set buzzer - pin as an output

inputString.reserve(200);

  mySerial.begin(9600);     // Set the baudrate of GSM module
  Serial.begin(9600);     //Set the baudrate of Serial monitor
  Serial.println("Initializing...");
  delay(1000);


  mySerial.println("AT"); //Once the handshake test is successful, it will back to OK
   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();
    mySerial.println("AT+CMGF=1"); 
   updateSerial();
    mySerial.println("AT+CNMI=1,2,0,0,0");
   updateSerial();
delay(1000);

}

void loop() {
	message();
	if (inputString.length()>0){
   tank_status(inputString);
   inputString="";
    delay(1000);
	}
}


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
  } 
}


void buzzer_sound(){
  Serial.println("buzzer sound start");
  tone(buzzer, 1000); // Send 1KHz sound signal...
  delay(30000);        // ...for 1 sec 1000, 30000 for 30 sec
  noTone(buzzer);     // Stop sound...
  Serial.println("buzzer sound stop");
  delay(1000);        // ...for 1sec
  }
  
 void message()
{
  
  while(mySerial.available()>0) 
  {
	char c = mySerial.read();
	inputString+=c;
  }
}

  
void tank_status(String message){
    //for tank 1 empty state
    if(strncmp(message, "@t1e#", 5) == 0){
      //Serial.println("Tank 1 Empty");
      digitalWrite(tank_1e, HIGH);
      digitalWrite(tank_1f, LOW);
      
      //uncomment below line to enable buzzer
      //buzzer_sound(); 
      }
      else if(strncmp(message, "@t1f#", 5) == 0){
        //Serial.println("Tank 1 Full");
      digitalWrite(tank_1e, LOW);
      digitalWrite(tank_1f, HIGH);
      
      //uncomment below line to enable buzzer
      //buzzer_sound(); 
        }
        else if(strncmp(message, "@t2e#", 5) == 0){
        //Serial.println("Tank 2 Empty");
      digitalWrite(tank_2e, HIGH);
      digitalWrite(tank_2f, LOW);
      
      //uncomment below line to enable buzzer
      //buzzer_sound(); 
        }
        else if(message, "@t2f#", 5) == 0){
        Serial.println("Tank 2 FULL");
      digitalWrite(tank_2e, LOW);
      digitalWrite(tank_2f, HIGH);
      
      //uncomment below line to enable buzzer
      //buzzer_sound(); 
        }
		
    // uncomment below for all 7 tanks

//        else if(message, "@t3e#", 5) == 0){
//        Serial.println("Tank 3 Empty");
//      digitalWrite(tank_3e, HIGH);
//      digitalWrite(tank_3f, LOW);
//      
//      //uncomment below line to enable buzzer
//      //buzzer_sound(); 
//        }
//        else if(message, "@t3f#", 5) == 0){
//        Serial.println("Tank 3 Full");
//      digitalWrite(tank_3e, LOW);
//      digitalWrite(tank_3f, HIGH);
//      
//      //uncomment below line to enable buzzer
//      //buzzer_sound(); 
//        }
//        else if(message, "@t4e#", 5) == 0){
//        Serial.println("Tank 4 Empty");
//      digitalWrite(tank_4e, HIGH);
//      digitalWrite(tank_4f, LOW);
//      
//      //uncomment below line to enable buzzer
//      //buzzer_sound(); 
//        }
//        else if(message, "@t4f#", 5) == 0){
//        Serial.println("Tank 4 Full");
//      digitalWrite(tank_4e, LOW);
//      digitalWrite(tank_4f, HIGH);
//      
//      //uncomment below line to enable buzzer
//      //buzzer_sound(); 
//        }
//        else if(message, "@t5e#", 5) == 0){
//        Serial.println("Tank 5 Empty");
//      digitalWrite(tank_5e, HIGH);
//      digitalWrite(tank_5f, LOW);
//      
//      //uncomment below line to enable buzzer
//      //buzzer_sound(); 
//        }
//        else if(message, "@t5f#", 5) == 0){
//        Serial.println("Tank 5 Full");
//      digitalWrite(tank_5e, LOW);
//      digitalWrite(tank_5f, HIGH);
//      
//      //uncomment below line to enable buzzer
//      //buzzer_sound(); 
//        }
//        else if(message, "@t6e#", 5) == 0){
//        Serial.println("Tank 6 Empty");
//      digitalWrite(tank_6e, HIGH);
//      digitalWrite(tank_6f, LOW);
//      
//      //uncomment below line to enable buzzer
//      //buzzer_sound(); 
//        }
//        else if(message, "@t6f#", 5) == 0){
//        Serial.println("Tank 6 Full");
//      digitalWrite(tank_6e, LOW);
//      digitalWrite(tank_6f, HIGH);
//      
//      //uncomment below line to enable buzzer
//      //buzzer_sound(); 
//        }
//        else if(message, "@t7e#", 5) == 0){
//        Serial.println("Tank 7 Empty");
//      digitalWrite(tank_7e, HIGH);
//      digitalWrite(tank_7f, LOW);
//      
//      //uncomment below line to enable buzzer
//      //buzzer_sound(); 
//        }
//        else if(message, "@t7f#", 5) == 0){
//        Serial.println("Tank 7 Full");
//      digitalWrite(tank_7e, LOW);
//      digitalWrite(tank_7f, HIGH);
//      
//      //uncomment below line to enable buzzer
//      //buzzer_sound(); 
//        }
//mySerial.write("AT+CMGD=1[4]") //delete message
    }