Home Automation Project

Hi All,

I’m a newbie on arduino.I’m doing a project where part of the requirements i have is to be able to turn the lights ON/OFF and get the STATUS of the lights via an SMS. The lights also need to be time controlled activated i.e. The lights must turn ON at 17:00PM and turn OFF at 08:00AM via SMS as well.

For the time controlled activation part i was thicking of sending an SMS with START date (START=17:00) and store this on EEPROM, then do a compare with the RTC

I have managed to get the below code to work with an assistance of a friend. This code seems to only work once for some reason I’m not able to figure out why. Can someone please help me to understand why this is behaving like that.

I also need some assistance on the time controlled actiavtion part, I know I will need to use the RTC for this part.

#include <SoftwareSerial.h>

SoftwareSerial SIM900(2,3); // RX, TX

int pin8 = 8;
int led13 = 13;
char buffer[9]; // eight char plus null terminator
char secret_code[] = "20!4#a1";
char secret_code1[] = "20!4#a0";
char secret_code2[] = "20!4#aS";
char incoming_char=0;
byte buffer_pos=0;
/*-----( Declare Constants )-----*/
#define RELAY_ON 1
#define RELAY_OFF 0

/*-----( Declare variables )-----*/
#define Relay_1  8  // Arduino Digital I/O pin number
#define Relay_2  7
#define Relay_3  6
#define Relay_4  5

void setup()
{               
  pinMode(pin8, OUTPUT);
  pinMode(led13, OUTPUT);
  digitalWrite(led13, LOW);
  digitalWrite(pin8, LOW);  // Set led to LOW

  pinMode(Relay_1, OUTPUT);   
  pinMode(Relay_2, OUTPUT);  
  pinMode(Relay_3, OUTPUT);  
  pinMode(Relay_4, OUTPUT);

  digitalWrite(Relay_1, RELAY_OFF);
  digitalWrite(Relay_2, RELAY_OFF);
  digitalWrite(Relay_3, RELAY_OFF);
  digitalWrite(Relay_4, RELAY_OFF);

  Serial.begin(19200); // set the baud rate
  SIM900.begin(19200); // for GSM shield
  delay(20000);  // give time to log on to network.
  SIM900.print("ATE0\r");
  SIM900.print("AT+CMGF=1\r");  // set SMS mode to text
  delay(100);
  SIM900.println("AT+CNMI=2,2,0,0,0\r");
  delay(100);
  Serial.println("Finished Setup Section");
}

void sendSMS(byte led_status)               
{
  SIM900.print("AT+CMGF=1\r");                     // AT command to send SMS message
  delay(1000);
  SIM900.println("AT + CMGS = \"+27XXXXXXXXXXX\"");  // recipient's mobile number, in international format
  delay(1000);
  if (led_status==0)
  {
    SIM900.println( " LIGHT STATUS: OFF");
  }
  else
  {
    SIM900.println( " LIGHT STATUS: ON");
  }
  delay(1000);
  SIM900.println((char)26);                        // End AT command with a ^Z, ASCII code 26
  delay(1000);
  SIM900.println();
  Serial.println("Message sent");
  delay(5000);     // give module time to send SMS 
}

void loop()
{
  if (SIM900.available()>0)
  {
    Serial.println("Reading incoming data");
    incoming_char=SIM900.read();
    if (incoming_char=='?')
    {
      Serial.println("Got a ?");
      delay(100);
      while (SIM900.available())
      {
        delay(100);
        incoming_char=SIM900.read();
        buffer[buffer_pos]=incoming_char;
        buffer_pos++;

        if (buffer_pos==7) // Already incremented
        {
          //Print it out
          buffer[buffer_pos]='\0';

          Serial.write(buffer);
          Serial.println();
          if (strcmp(buffer,secret_code)==0)
          {
            Serial.println("It's a match!"); 
            digitalWrite(pin8, HIGH);
            int led_status=digitalRead(pin8);
            Serial.print ("LED status = ");
            Serial.println(led_status);  // prints status on serial terminal
            sendSMS(led_status);

            delay(1000);              // wait for a second
          }
          buffer_pos=0;
          if (strcmp(buffer,secret_code1)==0)
          {
            Serial.println("It's a match!"); 
            digitalWrite(pin8, LOW);
            int led_status=digitalRead(pin8);
            Serial.print ("LED status = ");
            Serial.println(led_status);  // prints status on serial terminal
            sendSMS(led_status);

            delay(1000);              // wait for a second
          }
          buffer_pos=0;
          if (strcmp(buffer,secret_code2)==0)
          {
            Serial.println("It's a match!"); 
            int led_status=digitalRead(pin8);
            Serial.print ("LED status = ");
            Serial.println(led_status);  // prints status on serial terminal
            sendSMS(led_status);

            delay(1000);              // wait for a second
          }
          buffer_pos=0;
        }
      }
    }
  }
}

Any assistance will be highly appreciated.

It’s really not that difficult. I gave you all the information you needed to be able to work it out for yourself.

Hi Dan,

I will have a look at it again tonight.