diff --git a/ch-13/2.3-bluetooth/find_devices.py b/ch-13/2.3-bluetooth/find_devices.py
index 316c65b..44c2468 100644
--- a/ch-13/2.3-bluetooth/find_devices.py
+++ b/ch-13/2.3-bluetooth/find_devices.py
@@ -9,8 +9,7 @@ async def run():
     print([device.name for device in devices])
     matching_devices = [device for device in devices if device.name==ble_name]
     if len(matching_devices) == 0:
-        print(f"Could not find robot at {ble_name}")
-        return
+        raise RuntimeError("Could not find robot")
     ble_device_info = matching_devices[0]
     print(f"Found robot {ble_device_info.name}...")
 
diff --git a/ch-13/2.3-bluetooth/robot_ble_connection.py b/ch-13/2.3-bluetooth/robot_ble_connection.py
index 59953bd..91d37b1 100644
--- a/ch-13/2.3-bluetooth/robot_ble_connection.py
+++ b/ch-13/2.3-bluetooth/robot_ble_connection.py
@@ -22,9 +22,10 @@ class BleConnection:
         devices = await bleak.BleakScanner.discover(
             service_uuids=[self.ble_uuid]
         )
-        print(f"Found {len(devices)} devices")
-        print([device.name for device in devices])        
-        ble_device_info = [device for device in devices if device.name==self.ble_name][0]
+        matching_devices = [device for device in devices if device.name==self.ble_name]
+        if len(matching_devices) == 0:
+            raise RuntimeError("Could not find robot")
+        ble_device_info = matching_devices[0]
         print(f"Connecting to {ble_device_info.name}...")
         self.ble_client = bleak.BleakClient(ble_device_info.address)
         await self.ble_client.connect()
diff --git a/ch-13/3.1-displaying-a-pose/robot_ble_connection.py b/ch-13/3.1-displaying-a-pose/robot_ble_connection.py
index 66dd100..91d37b1 100644
--- a/ch-13/3.1-displaying-a-pose/robot_ble_connection.py
+++ b/ch-13/3.1-displaying-a-pose/robot_ble_connection.py
@@ -19,10 +19,13 @@ class BleConnection:
 
     async def connect(self):
         print("Scanning for devices...")
-        devices = await bleak.BleakScanner.discover(service_uuids=[self.ble_uuid])
-        print(f"Found {len(devices)} devices")
-        print([device.name for device in devices])        
-        ble_device_info = [device for device in devices if device.name==self.ble_name][0]
+        devices = await bleak.BleakScanner.discover(
+            service_uuids=[self.ble_uuid]
+        )
+        matching_devices = [device for device in devices if device.name==self.ble_name]
+        if len(matching_devices) == 0:
+            raise RuntimeError("Could not find robot")
+        ble_device_info = matching_devices[0]
         print(f"Connecting to {ble_device_info.name}...")
         self.ble_client = bleak.BleakClient(ble_device_info.address)
         await self.ble_client.connect()
diff --git a/ch-13/3.2-collision-avoidance/robot_ble_connection.py b/ch-13/3.2-collision-avoidance/robot_ble_connection.py
index 66dd100..91d37b1 100644
--- a/ch-13/3.2-collision-avoidance/robot_ble_connection.py
+++ b/ch-13/3.2-collision-avoidance/robot_ble_connection.py
@@ -19,10 +19,13 @@ class BleConnection:
 
     async def connect(self):
         print("Scanning for devices...")
-        devices = await bleak.BleakScanner.discover(service_uuids=[self.ble_uuid])
-        print(f"Found {len(devices)} devices")
-        print([device.name for device in devices])        
-        ble_device_info = [device for device in devices if device.name==self.ble_name][0]
+        devices = await bleak.BleakScanner.discover(
+            service_uuids=[self.ble_uuid]
+        )
+        matching_devices = [device for device in devices if device.name==self.ble_name]
+        if len(matching_devices) == 0:
+            raise RuntimeError("Could not find robot")
+        ble_device_info = matching_devices[0]
         print(f"Connecting to {ble_device_info.name}...")
         self.ble_client = bleak.BleakClient(ble_device_info.address)
         await self.ble_client.connect()
diff --git a/ch-13/3.3-moving-with-encoders/robot_ble_connection.py b/ch-13/3.3-moving-with-encoders/robot_ble_connection.py
index 66dd100..91d37b1 100644
--- a/ch-13/3.3-moving-with-encoders/robot_ble_connection.py
+++ b/ch-13/3.3-moving-with-encoders/robot_ble_connection.py
@@ -19,10 +19,13 @@ class BleConnection:
 
     async def connect(self):
         print("Scanning for devices...")
-        devices = await bleak.BleakScanner.discover(service_uuids=[self.ble_uuid])
-        print(f"Found {len(devices)} devices")
-        print([device.name for device in devices])        
-        ble_device_info = [device for device in devices if device.name==self.ble_name][0]
+        devices = await bleak.BleakScanner.discover(
+            service_uuids=[self.ble_uuid]
+        )
+        matching_devices = [device for device in devices if device.name==self.ble_name]
+        if len(matching_devices) == 0:
+            raise RuntimeError("Could not find robot")
+        ble_device_info = matching_devices[0]
         print(f"Connecting to {ble_device_info.name}...")
         self.ble_client = bleak.BleakClient(ble_device_info.address)
         await self.ble_client.connect()
diff --git a/ch-13/4.1-generating-weights/robot_ble_connection.py b/ch-13/4.1-generating-weights/robot_ble_connection.py
index 66dd100..91d37b1 100644
--- a/ch-13/4.1-generating-weights/robot_ble_connection.py
+++ b/ch-13/4.1-generating-weights/robot_ble_connection.py
@@ -19,10 +19,13 @@ class BleConnection:
 
     async def connect(self):
         print("Scanning for devices...")
-        devices = await bleak.BleakScanner.discover(service_uuids=[self.ble_uuid])
-        print(f"Found {len(devices)} devices")
-        print([device.name for device in devices])        
-        ble_device_info = [device for device in devices if device.name==self.ble_name][0]
+        devices = await bleak.BleakScanner.discover(
+            service_uuids=[self.ble_uuid]
+        )
+        matching_devices = [device for device in devices if device.name==self.ble_name]
+        if len(matching_devices) == 0:
+            raise RuntimeError("Could not find robot")
+        ble_device_info = matching_devices[0]
         print(f"Connecting to {ble_device_info.name}...")
         self.ble_client = bleak.BleakClient(ble_device_info.address)
         await self.ble_client.connect()