ToM LED Lighting using xmas led lights

If you have a broken string of LED Christmas tree lights, they're a great source of project LEDs. Usually they're 3.3-3.8V, 20mA bulbs.

Here's a simple (parametric) lighting U-mount for 6 LEDs that fits the thing-o-matic. No bolts are necessary, a built-in peg holds it to the z-platform.