diff --git a/esbo_etc/classes/__init__.py b/esbo_etc/classes/__init__.py
index 6c9b222..289e0c8 100644
--- a/esbo_etc/classes/__init__.py
+++ b/esbo_etc/classes/__init__.py
@@ -4,3 +4,4 @@ from .SpectralQty import *
 from .target import *
 from .optical_component import *
 from .RadiantFactory import *
+from .sensor import *