This Nozzle Light for the Prusa i3 was inspired by Maximpulse's floating LED light (https://www.thingiverse.com/thing:2237352). It allows you to shine light directly on the nozzle so you can see your print as it is printing.

His version runs a USB cable from the extruder to an external USB charger. Instead, I used a 12V to 5V USB buck converter, connected it to the Prusa's main power supply using the spare terminals and made a mount to clip onto the side of printer's power supply. (https://www.thingiverse.com/thing:2429603)

However, this still means you need to run a USB cable from the extruder and I found the cable was too thick to allow the printer to reach the top of the Z-axis (200mm).

This version holds the LED and the 5V converter in the same holder mounted on the extruder. The mount and hinge are combined and simplified so you can use the original fan screws and, because there is only one hinge, the light holder cannot be accidentally moved so it can hit the Z-screw. The hinge allows you to direct the light where you want.

The LED light is dimmable and turns on or off with a touch to the back side. The little tab on the end serves no purpose and can be cut off (use a Dremel). This allows you to get the actual LEDs 5mm closer to your work. Print the "LED-Buck Holder LeftShortened LED" if you cut yours. If, after installing, you decide the LED is too close to the printbed, just add a nut on the bolt between the LED-Buck Holder and the Extruder Mount.

The buck converter has a small red LED indicating it has power. The small hole in the back of the left side of the Holder is to allow you to insert a short piece of clear 1.75mm filament so the light shines. Not important but we all like little shining red lights.:-)

The USB LED touch light costs only £0.99 from China and can be found at:
https://www.ebay.co.uk/sch/i.html?\_from=R40&\_sacat=0&\_nkw=Touch%20LED%20USB&rt=nc&LH\_BIN=1&\_trksid=p2045573.m1684

The 12V to 5V USB buck converter is also only £0.99 from China and can be found at:
https://www.ebay.co.uk/sch/i.html?\_from=R40&\_trksid=p2380057.m570.l1313.TR1.TRC0.A0.H0.X12V+buck+converter+USB.TRS0&\_nkw=12V+buck+converter+USB&\_sacat=0

Print instructions

I printed using 0.10mm layer height and the bolts fitted fine. You can use a thicker layer but you may need to drill out the holes as they'll probably be a bit squashed.

Post-Printing

You'll need a 10mm M3 bolt to assemble the LED/Buck converter holder and a 15-20mm bolt to attach it to the extruder mount. Use the existing fan screws to attach the extruder mount to the extruder fan.

Solder a pair of wires to the converter, the negative connects to what I'm calling the "left" side (the side with the led -- see photo). The wire clip goes into the hexagonal hole on the back of the extruder at the top. It holds the wire flat against the back of the top of the extruder so it won't touch the z-frame or spool holders. Run the wire down to the long cable support bolt and use a wire tie. Wrap the wire around and along the main cable bunch then down, under the printer, to the main power supply. I chose to use connectors so I could easily remove the light if necessary. If you're really keen you could remove the spiral wrap and include the wire with the bundle -- nah, too much work.

Connecting the converter to the power supply is simple:DISCONNECT THE POWER Unscrew the PS from the printer (4 screws), unscrew the plastic cover (3 screws), slide the PS out leaving all wires connected. It will only slide a few inches but that's enough. Attach wires onto the spare 12VDC +/- terminals.Make sure you get your positives and negatives right!