Update auto-tune.py catch rtl failure

groundstation/auto-tune.py

@@ -18,8 +18,8 @@ if __name__ == "__main__":
         
 	sampling_rate = 1024e3 # 250e3 # Hz
 	duration = 65536/sampling_rate # 1          # seconds
-	t = np.linspace(0, duration, int(sampling_rate * duration), endpoint=False)
 	
+	try:	
 		sdr = RtlSdr()
 		
 		# configure device
@@ -32,7 +32,7 @@ if __name__ == "__main__":
 		# signal = sdr.read_samples(64*1024) #256
 		signal = sdr.read_samples(duration*sampling_rate).real #256
 		
-#	print(f"Center frequency is {center_frequency}")
+	#	print(f"Center frequency is {center_frequency}")
 		
 		sdr.close()
 		
@@ -50,6 +50,8 @@ if __name__ == "__main__":
 		
 		if (graph == 'y'):
 		  # Plotting the results
+		  t = np.linspace(0, duration, int(sampling_rate * duration), endpoint=False)
+			
 		  plt.figure(figsize=(12, 6))
 		  
 		  plt.subplot(1, 2, 1)
@@ -82,10 +84,10 @@ if __name__ == "__main__":
 		
 		offset = (np.argmax(x)*(150e3 - 10e3)/(9770 - 709))
 		freq_max = center_frequency + offset + 2000
+	except: # if no RTL-SDR or in use, stop scanning with high max value and center frequency
+		max_value = 100
+		freq_max = center_frequency + 200e3 # should be 434900000
 		
 	print(f" {freq_max:.0f} {max_value:.0f}")
-	#print(f"The minimum signal is {min_value} at frequency {freq_min}")
 
-	#print(min_value)
-	#print(max_value)