Read NFC Tag and Send its ID Number to your Phone via SMS

#include <PN532.h>
#include <SPI.h>


#define delaytime 2000
#define timeout1 5000
#define timeout2 7000

char number[20] = "13428979973";   //phone number
byte comm_buf[20];

const int LED = 3;

#define PN532_CS 10
PN532 nfc(PN532_CS);
//#define  NFC_DEMO_DEBUG 1
unsigned int frame_format;

unsigned char id_buffer[10];
uint32_t old_id;
unsigned long lasttime=0;
unsigned long prev_time=0;

unsigned char r_buffer[30];

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

  pinMode(LED,OUTPUT);
  digitalWrite(LED,HIGH);
  delay(1000);
  digitalWrite(LED,LOW);
  delay(10000);
  
	lasttime = millis();
    
}


void loop(void) {


	
  uint32_t id;
  // look for MiFare type cards
  id = nfc.readPassiveTargetID(PN532_MIFARE_ISO14443A);
  
  


		if (id != 0) 
		{
			if(old_id != id)
			{
				old_id = id;
				hex_to_dec(id);
				while(Serial.available())
					Serial.read();					
				Serial.println("AT+CMGF=1");
                prev_time = millis();
				int a=0;
				while((millis() - prev_time)<timeout1)
				{
					if(Serial.available())
					{
						
						r_buffer[a++]=Serial.read();
						
						if(strstr((char *)r_buffer, "OK"))
							break;
					
					}
					
					
				}
				Serial.print("AT+CMGS=\"");
				Serial.print(number);
				Serial.println("\"");
				prev_time = millis();
				a=0;
				while((millis() - prev_time)<timeout2)
				{
					if(Serial.available())
					{
						
						r_buffer[a++]=Serial.read();
						
						if(strstr((char *)r_buffer, ">"))
							break;
					
					}
					
					
				}
				Serial.print("card: ");
				for(unsigned char i=0;i<10;i++)
				{
					Serial.write(id_buffer[i]);
				}
				char buf_end[2];
				buf_end[0]=0x1a;
				buf_end[1]='\0';
				Serial.println(buf_end);
				prev_time = millis();
				a=0;
				while((millis() - prev_time)<timeout2)
				{
					if(Serial.available())
					{
						
						r_buffer[a++]=Serial.read();
						
						if(strstr((char *)r_buffer, "OK"))
							break;
					
					}
					
					
				}
                
			
			}

				lasttime = millis();


			

		}