diff --git a/photobooth/gpio/__init__.py b/photobooth/gpio/__init__.py
index d0f4525..49f5387 100644
--- a/photobooth/gpio/__init__.py
+++ b/photobooth/gpio/__init__.py
@@ -106,7 +106,7 @@ class Gpio:
     def exit(self):
 
         self._comm.send(
-            Workers.Master,
+            Workers.MASTER,
             StateMachine.TeardownEvent(StateMachine.TeardownEvent.WELCOME))
 
     def showIdle(self):