Update README.md

RentersLightSwitch/README.md

@@ -35,7 +35,7 @@ _Note: Don't add the servo arm until you've tested the code because it needs to
 ![Lightswitch_Fritz](/RentersLightSwitch/lightswitch_fritz.png "Lightswitch Fritz")
 
 ## Upload and Test ##
-Upload the code with Arduino, however you usually do that, install the switchplate and hide the board somewhere near the lightswitch (mine conveniently runs behind a cabinet) and power up.
+Upload [the code with Arduino](RentersLightSwitch/lightswitch.ino), however you usually do that, install the switchplate and hide the board somewhere near the lightswitch (mine conveniently runs behind a cabinet) and power up.
 
 Once it starts up the servo should find it's default "neutral" rotation, now you can add the two sided servo arm at an angle that is neither on nor off.