diff --git a/MainCode/adalm1000_logger.py b/MainCode/adalm1000_logger.py
index 06e6694..88efa5f 100644
--- a/MainCode/adalm1000_logger.py
+++ b/MainCode/adalm1000_logger.py
@@ -75,9 +75,9 @@ class MeasurementThread(QThread):
                     raw_voltage = np.mean([s[1][0] for s in samples])
                     raw_current = np.mean([s[0][1] for s in samples])
                     
-                    if voltage_window.size() >= self.filter_window_size:
-                        voltage_window.append
-                        current_window.append
+                    if len(voltage_window) >= self.filter_window_size:
+                        voltage_window.popleft()
+                        current_window.popleft()
                     
                     voltage_window.append(raw_voltage)
                     current_window.append(raw_current)
@@ -614,14 +614,19 @@ class BatteryTester(QMainWindow):
         self.cleanup_device()
         
         try:
-            # Delay to avoid "Device busy" errors
-            time.sleep(1.5)
-            
-            self.session = pysmu.Session(ignore_dataflow=True, queue_size=10000)
-            if not self.session.devices:
-                raise Exception("No ADALM1000 detected - check connection")
+            print("Waiting before initializing session...")
+            time.sleep(1.5)  # Delay helps avoid "device busy" issues
 
+            self.session = pysmu.Session(ignore_dataflow=True, queue_size=10000)
+            
+            # 🔍 Log detected devices
+            print(f"Devices found: {self.session.devices}")
+            
+            if not self.session.devices:
+                raise Exception("No ADALM1000 detected - check USB connection")
+            
             self.dev = self.session.devices[0]
+            
             # Reset channels
             self.dev.channels['A'].mode = pysmu.Mode.HI_Z
             self.dev.channels['B'].mode = pysmu.Mode.HI_Z
@@ -630,6 +635,7 @@ class BatteryTester(QMainWindow):
             
             self.session.start(0)
 
+            # Update UI
             self.status_light.setStyleSheet("background-color: green; border-radius: 10px;")
             self.connection_label.setText("Connected")
             self.status_bar.setText("Device connected | Ready for measurement")
@@ -644,17 +650,19 @@ class BatteryTester(QMainWindow):
 
     def cleanup_device(self):
         """Clean up device resources."""
+        print("Cleaning up device session...")
+        
         # Stop measurement thread
         if self.measurement_thread is not None:
             try:
                 self.measurement_thread.stop()
-                if not self.measurement_thread.wait(1000):  # 1 second timeout
+                if not self.measurement_thread.wait(1000):
                     print("Warning: Measurement thread didn't stop cleanly")
                 self.measurement_thread = None
             except Exception as e:
                 print(f"Error stopping measurement thread: {e}")
-
-        # Clean up session
+        
+        # Stop and delete session
         if hasattr(self, 'session'):
             try:
                 if self.session_active:
@@ -662,12 +670,13 @@ class BatteryTester(QMainWindow):
                     self.session.end()
                     self.session_active = False
                 del self.session
+                print("Session ended successfully")
             except Exception as e:
-                print(f"Error cleaning up session: {e}")
+                print(f"Error ending session: {e}")
             finally:
                 self.session_active = False
 
-        # Reset UI status
+        # Reset UI indicators
         self.status_light.setStyleSheet("background-color: red; border-radius: 10px;")
         self.connection_label.setText("Disconnected")
         self.start_button.setEnabled(False)
@@ -878,10 +887,10 @@ class BatteryTester(QMainWindow):
 
     def update_measurements(self, voltage: float, current: float, current_time: float):
         """Update measurements in the UI."""
-        if self.time_data.size() > 10000:  # Limit data points
-            self.time_data.append
-            self.voltage_data.append
-            self.current_data.append
+        if len(self.time_data) > 10000:  # Limit data points
+            self.time_data.popleft()
+            self.voltage_data.popleft()
+            self.current_data.popleft()
             
         self.time_data.append(current_time)
         self.voltage_data.append(voltage)
@@ -893,7 +902,7 @@ class BatteryTester(QMainWindow):
         self.time_label.setText(self.format_time(current_time))
         
         # Update plot periodically
-        if self.time_data.size() % 10 == 0:
+        if len(self.time_data) % 10 == 0:
             self.update_plot()
         
         # Log data if test is running