Quote Originally Posted by dacb View Post
Again, this is great information. I actually copied your approach for the LED strips under the X-carriage, but haven't wired them up yet. I'm thinking of putting them on D9 (IIRC) of the RAMPS board so they only run during the print process.
There's nothing wrong with wiring them to D9, but you'll have to remember to tell your slicer to enable cooling so that D9 gets turned on for the print. Personally, I'd save D9 for the option of adding a print cooling fan. You may find you want those LEDs on more than you think - when checking bed clearance, when manually extruding after a color change, when wiping off the hot end nozzle, etc. If you followed my LED scheme, note that clough42's revised hex hot end shroud system uses a different baseplate on the X-carriage that has a 25mm fan right where you probably have those undercarriage LEDs.