diff --git a/lora_pingpong.py b/lora_pingpong.py
index 60f9cf5..4813c9b 100644
--- a/lora_pingpong.py
+++ b/lora_pingpong.py
@@ -12,9 +12,15 @@ You should have received a copy of the GNU General Public License along with thi
 
 from SX127x import SX127x
 from machine import Pin, SPI
-from time import sleep, time_ns
+from time import sleep, time
 from json import loads
 
+def blink_led(pin, sleep_time=0.2):
+    pin = Pin(pin, Pin.OUT)
+    
+    pin.value(1)
+    sleep(sleep_time)
+    pin.value(0)
 
 def as_initializer(lora, lcd, lcd_connected, interrupt_pin):
     ping_to_send = True
@@ -23,22 +29,36 @@ def as_initializer(lora, lcd, lcd_connected, interrupt_pin):
     RSSI_REQ = -1
     SNR_REQ = -1
     
-    while True:
+    # pin definitions
+    interrupt = None
+    if interrupt_pin:
+        interrupt = Pin(interrupt_pin, Pin.OUT)
+    # the lambda only returns true true if a pin is specified and it is pulled high (btn pressed)
+    interrupted = lambda: interrupt.value() == 1 if interrupt else False
+    receive_led = 26
+    send_led = 27
+    
+    while not interrupted():
         if ping_to_send:
             COUNT += 1
             msg = '{"type": "ping", "count": ' + str(COUNT) + ', "tx_power": ' + str(lora._tx_power_level) + '}'
             if lcd_connected:                
                 lcd.move_to(14,0)
                 lcd.putstr(">")
+                lcd.move_to(0,1)
+                lcd.putstr("Waiting for pong")
             print(f"[LoRaPingPong] Sending ping: {msg}")
             lora.println(msg)
+            blink_led(send_led)
             ping_to_send = False
         if not ping_to_send:
             print("[LoRaPingPong] Now waiting for a response")
             while not lora.received_packet():
                 sleep(0.01)
+                if interrupted(): return  # if interrupt btn is pressed, stop listening
                 # TODO: implement a timeout
             # NOW got a response!
+            blink_led(receive_led)
             payload = lora.read_payload()
             try:
                 payload_dict = loads(payload)
@@ -62,7 +82,10 @@ def as_initializer(lora, lcd, lcd_connected, interrupt_pin):
                 lcd.putstr(f"LoRaPingPong [<]")
             print(f"[LoRaPingPong] Got a response: {payload}")
             print(f"[LoRaPingPong] Now waiting some time for next ping! Wo-hoo!")
-            sleep(10)  # sleep 10 seconds
+            # sleep 10 seconds
+            time_now = time()
+            while (time() - time_now) < 10:
+                if interrupted(): return  # end ping pong when btn at interrupt_pin is pressed (given as param)
             ping_to_send = True
     
 
@@ -73,13 +96,29 @@ def as_responder(lora, lcd, lcd_connected, interrupt_pin):
     RSSI_REQ = -1
     SNR_REQ = -1
     
-    while True:
+    # pin definitions
+    interrupt = None
+    if interrupt_pin:
+        interrupt = Pin(interrupt_pin, Pin.OUT)
+    # the lambda only returns true true if a pin is specified and it is pulled high (btn pressed)
+    interrupted = lambda: interrupt.value() == 1 if interrupt else False
+    receive_led = 26
+    send_led = 27
+    
+    # print waiting for ping at startup (if lcd's connected)
+    if lcd:
+        lcd.move_to(0,1)
+        lcd.putstr("Waiting for ping")
+    
+    while not interrupted():  # run as long the interrupt pin is low (btn not pressed)
         if to_wait_for_ping:  # wait for ping
             print("[LoRaPingPong] Waiting for a ping (request)")
             while not lora.received_packet():
                 sleep(0.01)
+                if interrupted(): return  # if interrupt btn is pressed, stop listening
                 # TODO: implement a timeout
             # NOW got a response!
+            blink_led(receive_led)
             payload = lora.read_payload()
             try:
                 payload_dict = loads(payload)
@@ -116,6 +155,7 @@ def as_responder(lora, lcd, lcd_connected, interrupt_pin):
                 lcd.putstr(f"LoRaPingPong [>]")
             print(f"[LoRaPingPong] Sending pong (response): {msg}")
             lora.println(msg)
+            blink_led(send_led)
             to_wait_for_ping = True
 
 
@@ -151,7 +191,7 @@ def pingpong(lora, initializer: bool, lcd_connected=True, interrupt_pin=None):
         lcd = I2C_LCD(_i2c, 0x27, 2, 16)
         
         lcd.move_to(0,0)
-        lcd.putstr(f"LoRaPingPong [ ]Waiting for ping")
+        lcd.putstr(f"LoRaPingPong [ ]")
     
     # infinite loop running the ping at first
     if initializer:
@@ -182,22 +222,24 @@ parameters = {
         'invert_IQ': False,
         }
 
-lora = SX127x(device_spi, pins={"dio_0": 6, "ss": 5, "led": 27}, parameters=parameters)
+lora = SX127x(device_spi, pins={"dio_0": 6, "ss": 5, "led": 7}, parameters=parameters)
 
 
 # The run function (for different options; see below the "if __name__ == ..." section)
 
 def run_lcd_init():
-    pingpong(lora, initializer=True, lcd_connected=True)
+    pingpong(lora, initializer=True, lcd_connected=True, interrupt_pin=8)
 def run_wo_lcd_init():
-    pingpong(lora, initializer=True, lcd_connected=False)
+    pingpong(lora, initializer=True, lcd_connected=False, interrupt_pin=8)
 def run_lcd_resp():
-    pingpong(lora, initializer=False, lcd_connected=True)
+    pingpong(lora, initializer=False, lcd_connected=True, interrupt_pin=8)
 def run_wo_lcd_resp():
-    pingpong(lora, initializer=False, lcd_connected=False)
+    pingpong(lora, initializer=False, lcd_connected=False, interrupt_pin=8)
     
 if __name__ == "__main__":
     #run_lcd_resp()  # run as responder (with lcd)
     #run_wo_lcd_resp()  # run as responder (without lcd)
-    #run_lcd_init()  # run as initializer (with lcd)
-    run_wo_lcd_init()  # run as initializer (without lcd)
+    run_lcd_init()  # run as initializer (with lcd)
+    #run_wo_lcd_init()  # run as initializer (without lcd)
+
+    print("Finished execution")