diff --git a/simulation/src/nuevisim.cpp b/simulation/src/nuevisim.cpp
index f7b3429..3388e1e 100644
--- a/simulation/src/nuevisim.cpp
+++ b/simulation/src/nuevisim.cpp
@@ -63,6 +63,7 @@ extern void doorKnobCheck(void);
 extern void portOn(void);
 extern void portOff(void);
 extern void port(void);
+extern void readTeensySwitches(void);
 extern void readSwitches(void);
 extern int patchLimit(int value);