SMS Relay

#include <SoftwareSerial.h>
#define debug Serial

char input[1024]; // variable to store the incoming characters
int rdy = 0, rdyStart = 0;

//SoftwareSerial debug(4, 5);  //RX, TX
SoftwareSerial sms(4, 5);  //RX, TX
const int Relay = 8;
const int SMSReset = 7;

void sendCommand(const char* cmd, int prnt = 1){
  sms.println(cmd);
  delay(300);

  char buf[128];
  int x=0;
  while(sms.available()){
    buf[x++] = sms.read();
  }
  if(prnt && x){
    buf[x++] = 0;
    debug.write(buf);
  }
}


void echoState(int state){
  sendCommand(strcat("ATE", String(state).c_str()), 0);
}

void initSMS(){
  debug.println("SMS Init...");
  echoState(0);
  sendCommand("AT"); //Check AT Status

  //Get device information
  sendCommand("AT+CMEE=2");
  sendCommand("AT+CGMI");
  sendCommand("AT+CGMM");
  sendCommand("AT+CGMR");
  sendCommand("AT+CGSN");
  sendCommand("AT+CPAS");
  sendCommand("AT+CSQ");
  echoState(1);

  sendCommand("AT+CMGF=1"); // set SMS mode to text
  sendCommand("AT+CNMI=2,2,0,0,0"); // just to get a notification when SMS arrives &direct out SMS upon receipt to the GSM serial out
}

void setup() {
  debug.begin(9600);
  debug.println("Device Initializing...");

  pinMode(Relay, OUTPUT);
  pinMode(SMSReset, OUTPUT);
  memset(input, 0, sizeof(input)); //clear input buffer

  digitalWrite(Relay, LOW);
  digitalWrite(SMSReset, LOW);

  delay(500);

  // wake up the GSM shield
  sms.begin(9600);
  digitalWrite(SMSReset, HIGH);
  delay(500);
  sms.println("");  //Needed for starting AT communication on serial
  rdyStart = millis() / 1000;
}

void executeCommand(){
  if(!strcmp(input, "$a0")){
      debug.println("Relay OFF");
      digitalWrite(Relay, LOW);
  } else if(!strcmp(input, "$a1")) {
    debug.println("Relay ON");
    digitalWrite(Relay, HIGH);
  } else {
    debug.println(strcat("Unknown Command: ", input));
  }
  sms.println("AT+CMGD=1,4"); // delete all SMS
  delay(1000);
}

void loop(){


  //If a character comes in from the GSM...
  int i = 0;
  while(sms.available()){
    input[i++] = sms.read();
    delay(50);
  }

  { //Debug listener scope
    char buf[128];
    int x=0;
    while(debug.available()){
      buf[x++] = debug.read();
      if(buf[x-1] == '~') buf[x-1] = 26;
    }
    if(x){
      buf[x++] = 0;
      sms.write(buf);
    }
  }

  if(i){  //Output SMS data
    input[i++] = 0; //null terminate our string
    debug.println("OUTPUT:");
    debug.println(input);
    debug.println("--------------------");
    //executeCommand(); //Execute SMS command
    i = 0;
  }


  if(!rdy && millis()/1000 - rdyStart >= 3){
      rdy = 1;
      initSMS();
  }

}