Hi, im new here and I want to convert a hasbro bladebuilder Darth Vader lightsaber. I want to build it like in this diagram: http://forums.thecustomsabershop.com...5&d=1447018773
I will build it with an 18650 cell and an charging modul with low voltage protection.
And I have a cree XML t6 led in red and I want to know what kind of resistor I need?

Im thankful if someone can help me.