diff --git a/interface.hpp b/interface.hpp
index e8ec28e..4b157dc 100644
--- a/interface.hpp
+++ b/interface.hpp
@@ -29,6 +29,11 @@
     server::OperationalStatus;
 using StatusObject = ServerObject<StatusInterface>;
 
+// I understand this seems like magic, but since decltype doesn't evaluate you
+// can call nullptr https://stackoverflow.com/a/5580411/2784885
+using SensorValueType =
+    decltype((static_cast<ValueInterface*>(nullptr))->value());
+
 enum class InterfaceType
 {
     VALUE,