diff --git a/service.py b/service.py
index 504abfa..655e348 100755
--- a/service.py
+++ b/service.py
@@ -4,48 +4,131 @@ import time
 import subprocess
 import pwmio
 import board
+import logging
+import threading
+from logging.handlers import RotatingFileHandler, TimedRotatingFileHandler
+import signal
 
-piezo = pwmio.PWMOut(board.D15, variable_frequency=True)
-piezo.duty_cycle = 0
-piezo.frequency = 523
+class GracefulKiller:
+  kill_now = False
+  def __init__(self):
+    signal.signal(signal.SIGINT, self.exit_gracefully)
+    signal.signal(signal.SIGTERM, self.exit_gracefully)
 
-ups_loc = subprocess.check_output(['sudo','/bin/bash','kill.sh'])
-ups_loc = ups_loc.decode("UTF-8")
-ups_loc = ups_loc.replace("\n", "")
-ser = serial.Serial(ups_loc, 9600)
+  def exit_gracefully(self, signum, frame):
+    self.kill_now = True
+    log.info('UPS service is being stopped')
 
-def swr(a):
-    a = bytes(a, 'utf-8')
-    ser.write(a)
-    a = ser.readline().decode("UTF-8")
-    a = a.replace("\n", "")
-    a = a.replace("\r", "")
-    a = a.replace("#", "")
-    a = a.replace("@", "")
-    return(a)
+class UPS:
+    def __init__(self):
+        ups_loc = subprocess.check_output(['sudo','/bin/bash','kill.sh'])
+        ups_loc = ups_loc.decode("UTF-8")
+        ups_loc = ups_loc.replace("\n", "")
+        self.ser = serial.Serial(ups_loc, 9600)
+
+    def get_firmver(self):
+        return self.__get('@Fx#').replace("F","").replace("-",".")
+
+    def get_curvol(self):
+        return self.__get('@V0#').replace("V","")
+
+    def get_chargestat(self):
+        a = self.__get('@C0#').replace("","")
+        if a == "CF0C0":
+            return "err"
+        elif a == "CF1C0":
+            return "chg"
+        elif a == "CF0C1":
+            return "full"
+        elif a == "CF1C1":
+            return "dch"
+
+    def shutdown(self):
+        self.__get('@Px#')
+
+    def __get(self,a):
+        a = bytes(a, 'utf-8')
+        self.ser.write(a)
+        a = self.ser.readline().decode("UTF-8")
+        a = a.replace("\n", "")
+        a = a.replace("\r", "")
+        a = a.replace("#", "")
+        a = a.replace("@", "")
+        return(a)
+
+class Logger:
+    def __init__(self):
+        self.logger = logging.getLogger()
+        self.logger.setLevel(logging.INFO)
+        formatter = logging.Formatter('%(asctime)s %(levelname)s: %(message)s', datefmt='%Z %Y:%m:%d %H:%M:%S')
+        file_handler = RotatingFileHandler('./log/ups.log', maxBytes=1024*1024*10, backupCount=10)
+        file_handler.setFormatter(formatter)
+        consoleHandler = logging.StreamHandler()
+        consoleHandler.setFormatter(formatter)
+        self.logger.addHandler(file_handler)
+        self.logger.addHandler(consoleHandler)
     
-prt = str()
-while True:
-    print("------------------------------------------------------")
-    print("------------------------------------------------------")
-    a = swr('@Fx#').replace("F","")
-    print("firmware ver ",a)
-    vol = swr('@V0#').replace("V","")
-    print("current voltage "+vol+"mV")
-    a = swr('@C0#').replace("","")
-    if a != "CF1C1":
-        piezo.duty_cycle = 0
-        print("Power Status Normal")
-    elif a == "CF0C0":
-        print("UPS !ERROR!")
-    else:
-        print("Power Loss Detect")
-        piezo.duty_cycle = 45000
-        if int(vol) <= 3600:
-            ser.write(b'@Px#')
+    def debug(self,message):
+        self.logger.debug(message)
+
+    def info(self,message):
+        self.logger.info(message)
+
+    def warn(self,message):
+        self.logger.warning(message)
+
+    def error(self,message):
+        self.logger.error(message)
+
+    def crit(self,message):
+        self.logger.critical(message)
+
+class Alarm:
+    def __init__(self):
+        self.piezo = pwmio.PWMOut(board.D15, variable_frequency=True)
+        self.piezo.duty_cycle = 0
+        self.piezo.frequency = 523
+
+    def on(self):
+        self.piezo.duty_cycle = 45000
+
+    def off(self):
+        self.piezo.duty_cycle = 0
+
+killer = GracefulKiller()
+log = Logger()
+log.info('UPS service is starting')
+ups = UPS()
+buz = Alarm()
+
+buz.on()
+log.info('UPS service started successfully')
+log.info(f"UPS Firmware Ver {ups.get_firmver()}")
+time.sleep(0.3)
+buz.off()
+
+while not killer.kill_now:
+    ps = ups.get_chargestat()
+
+    if ps == "full":
+        log.info("AC power active")
+    elif ps == "chg":
+        log.info('AC power restored Charging')
+    elif ps == "dch":
+        log.warn('AC power loss')
+        pw = int(ups.get_curvol())
+        if pw <= 3500:
+            ups.shutdown()
             os.system("shutdown now")
-    print("------------------------------------------------------")
-    print("------------------------------------------------------")
-    time.sleep(1)
-    piezo.duty_cycle = 0
-    time.sleep(1)
+            log.crit('battery is too low Shut down system')
+        elif pw <= 3800:
+            log.warn('battery is low')
+        elif pw <= 3650:
+            log.crit('battery is too low')
+    elif ps == "err":
+        log.crit('UPS hardware error detect')
+
+    log.info("Current Voltage "+ups.get_curvol()+"mV")
+    time.sleep(0.5)
+
+log.info('UPS service stopped successfully')