Can't see what is going on on your print? Print head is always shading the bit you want to see? Enjoy printing in the dark?
This is for you...
The Ultimaker has a 19v feed for LEDs, which equates to 5 cheap white 5mm LEDs, with a Vf of 3.8volts wired in series.
I modelled up some fittings to hold them discretely, whilst out of the way of the mechanism.
You need one of the top lights, and two of the side lights, and two mirrored side lights.
I used 55000mcd LEDs I previously bought from a HongKong seller on eBay, very cheap. They are too narrow angle though, I would suggest 40degree angle is better.
The top lamp swivels in the hole above the Z axis screw, so you can twist it to look where you need.
Cut the LED legs short (5mm ish) and solder a wire onto each. Push into the printed fitting and fix with hot melt glue.
Remove the bearing caps, and replace with the lights, feeding the wire down the existing cable guides, solder together in series and join to the 19vLED feed on the PCB.
Modelled in Siemens NX8 - printed at 0.1mm slice, 50% fill with Cura.
Happy nightime printing!