diff --git a/MQTT.py b/MQTT.py
index 8d7954c..8f4d49a 100644
--- a/MQTT.py
+++ b/MQTT.py
@@ -11,19 +11,19 @@ def on_connect(client, userdata, flags, rc):
     if rc == 0:
         client.subscribe('lot_mqtt')
 
-
 def valid(msg, client):
     p = subprocess.Popen(['cat /home/pi/device_name'], shell=True, stdout=subprocess.PIPE, stderr=subprocess.PIPE)
     out, err = p.communicate()
     device_name = out.decode('utf-8')
     origin_data = json.loads(msg.payload.decode('utf-8'))
+    device_name = str(device_name)
     if 'msg' not in origin_data:
         client.publish('error', payload='msg must be supplied', qos=0)
         return False
     if 'device_name' not in origin_data:
         client.publish('error', payload='device_name must be supplied', qos=0)
         return False
-    if origin_data['device_name'] != device_name:
+    if str(origin_data['device_name']) != str(device_name):
         return False
     return True