def Start_Class(boo):
     RDC.setison(boo)
     RDC.buz()
     RDC.buz()
     currentT = RDC.getCT()
     XL.setClassS()
     EOC = RDC.getEOC()
     zero = RDC.setT(0,0)
     while((EOC-RDC.getCT())>zero):
         print "time out"
         if(RDC.getison()):
             print "3"
             ext = EasyProcess('/home/pi/libnfc/libnfc-1.7.1/examples/nfc-poll').call(timeout=5).stdout
             print " 4"
             if(ext):
                 temp = RDC.formatC(ext)
                 if(temp == "d198290f"):
                     break;
                 XL.placeStudent(temp,currentT)
                 #take photo and record him/her
                 RDC.buz()
                 print("student added")
         else:
             RDC.setinc(False)   
             break;
     RDC.buz()
     RDC.buz()
     RDC.buz()
     XL.incLectDay()
     day = XL.getLectDay()
     lecture = XL.getLD()
     if(day > lecture):
         showerror(title="Error",message="That was the last day of class.")
     RDC.setinc(True)