Minor fix

rpi/main.py

@@ -4,12 +4,15 @@ from hardware.screen.screen import Screen
 from hardware.rfid.reader import RfidReader
 from services.mqtt_service import MQTTService
 
+screen = Screen()
+
 def publish(uid : int) :
-    screen = Screen()
     screen.displayMessage(str(uid))
     service.publish("app", "game/start", str(uid), 0)
 
 if __name__ == "__main__":
+    screen.enableBackground()
+    screen.displayMessage("Waiting for scan...")
     service = MQTTService("127.0.0.1", 1883)
     reader = RfidReader("/dev/serial0", 9600)
     reader.subscribe(publish)