This project started with a goal to save power (light) when printing on my MK3 Octopi fitted 3d-printer over nights. The modified nozzle hosts 2xTO1 bright white LEDs and 2x100 Ohms resistors, while the nozzle fan holder was modified to host a mini rocker switch. The GND and 5V power are drawn from the line that feeds the Noctua fan, and as such the lighting is enabled as soon as the nozzle heats up. This can be suppressed by flipping the mini rocker, and is also automatically achieved when the Noctua shuts off after printing. The parts were made with PETG and printed on my MK3.

4 major improvements to simplify printing, assembly and insure better attachment to the extruder cover are presented in the revised version4. The led holder is now a single piece merging the nozzle and holder, bridging where the switch is located and integrating the wiring. Only the 2 leads (5V PWR & GND) exit on the side and are to be connected to the Noctua fan safely or another 5V source if you may opt for that route. I noticed no degradation when connecting to the Noctua fan! Attachment to the extruder cover is via 3 points (2 M3X10 and an additional M3x8 and square nut were placed in the right corner of the R4 modified extruder cover. The system holds well the angled cooling fan as depicted. Prints were prototyped with OpenSCAD, importing the existing MK3 designs and all produced on my MK3 units, in Orange and Black Prusa PETG as well as in my favorite transparent Blue PETG. The prints were realized without support, using a 0.4mm standard nozzle and the Prusa PETG Slic3r defaults with 20% fill and 0.2mm layer thickness. 

This brings me to the 4th and last improvement you will notice on both the modified extruder cover R4 and the modified bozzle fan holder R4: a recycling PET logo is imprinted, in an effort to facilitate end-of-life of the printed part recycling. I would encourage everyone to include on prototyped parts to facilitate the recycling process and contribute to a greener planet footprint moving forward!

Note that this assembly now reduced the number of parts from 3 to 2 and insured better mounting and rigidity. The weight difference is minimal: 276 vs 220 in the existing MK3 version.

Hope you will enjoy the impact when monitoring your MK3 with Octoprint camera in the night hours and even in not so well lit (basement?) areas. Enjoy!