Model originally uploaded to Thingiverse at https://www.thingiverse.com/thing:2318065.

I cannot get Simplify3D to not print the top of the cone (so light can shine thru) so I had some prints where I just drilled the hole out and some I stopped the printing short to get the opening.

I started out whit Micro Center LED strip:

http://www.microcenter.com/product/391704/Blue_5_LED_Lazer_Light

and remove the board from the casing. I cut it down to keep only 1 LED and 1 resistor.

I used, for now, the provided velcro to attach this thing to the extruder.

For power, since this LED was rated 12V, I piggy back from the extruder fan wire which is also 12V and it is on all the time.

Now I can see the extrusion going on without having to manually flash some light!!!

ENJOY!

UPDATE 30May17 I have removed the velcro and attached the wire to a rubber coated twistie tie. This way I can move the light around to fine tune it. Work good so far.