diff --git a/doorbell/klingel_sender_nano_serial/doorbell.py b/doorbell/klingel_sender_nano_serial/doorbell.py
index b1fe600..f2d8b12 100644
--- a/doorbell/klingel_sender_nano_serial/doorbell.py
+++ b/doorbell/klingel_sender_nano_serial/doorbell.py
@@ -20,6 +20,11 @@ logger.info('Initializing')
 
 
 arduino = serial.Serial('/dev/Doorbell', 9600, timeout=.1)
+# for ESP32
+#arduino.setDTR(False)
+#arduino.setRTS(False)
+
+last_ring = time.time()
 
 while True:
     data = arduino.readline()[:-2] #the last bit gets rid of the new-line chars
@@ -35,14 +40,16 @@ while True:
             try:
                 response = urllib.request.urlopen('http://192.168.178.60/bell/on', timeout=5).read().decode('utf-8')
 
-                # send MQTT
-                headers = {
-                    "Authorization": "Bearer eyJ0eXAiOiJKV1QiLCJhbGciOiJIUzI1NiJ9.eyJpc3MiOiJjYjY5NjA5NmY0N2E0NmZlOGEzYjczOGYzYmUzOTk5ZSIsImlhdCI6MTY2MTM0NDgxOSwiZXhwIjoxOTc2NzA0ODE5fQ.z9fzbVOA1Pbur3Zb07481n-SoYesj8cetw-CX6WPmTs",
-                    "Content-Type": "application/json"
-                }
-                data = json.dumps({'payload': 'RING', 'topic': 'lewe/doorbell', 'retain': 'False'}).encode('utf8')
-                request = urllib.request.Request("https://www.nodebucket.de:8123/api/services/mqtt/publish", data, headers)
-                response = urllib.request.urlopen(request)
+                # send MQTT if last ring was more than 5 seconds ago
+                if ((time.time() - last_ring) > 5):
+                    last_ring = time.time()
+                    headers = {
+                        "Authorization": "Bearer eyJ0eXAiOiJKV1QiLCJhbGciOiJIUzI1NiJ9.eyJpc3MiOiJjYjY5NjA5NmY0N2E0NmZlOGEzYjczOGYzYmUzOTk5ZSIsImlhdCI6MTY2MTM0NDgxOSwiZXhwIjoxOTc2NzA0ODE5fQ.z9fzbVOA1Pbur3Zb07481n-SoYesj8cetw-CX6WPmTs",
+                        "Content-Type": "application/json"
+                    }
+                    data = json.dumps({'payload': 'RING', 'topic': 'lewe/doorbell', 'retain': 'False'}).encode('utf8')
+                    request = urllib.request.Request("https://www.nodebucket.de:8123/api/services/mqtt/publish", data, headers)
+                    response = urllib.request.urlopen(request)
             except Exception:
                 logger.error("Could not ring doorbell")
                 time.sleep(300)
\ No newline at end of file