Detect when the system isn't connected

server/main.py

@@ -99,11 +99,18 @@ def session_post(cid):
     # go through the photo taking process
     status = 'Warming up'
 
-    # warmup
-    power.lights_on()
-    time.sleep(4)
-    power.lights_off()
-    time.sleep(0.5)
+    try:
+        # warmup
+        power.lights_on()
+        time.sleep(4)
+        power.lights_off()
+        time.sleep(0.5)
+    except BaseException as e:
+        print('Problem with lights: {} - {}'.format(e.__class__.__name__, str(e)))
+        print()
+        print('Are you sure the system is connected?')
+        print()
+        abort(500)
 
     status = 'Capturing'