Wonderful Walter Cooke

24 LED Modulated and Un-modulated Phototherapy Light Wand Schematic

Schematic for 24 LED Phototherpay Light Wand

I used a small slide switch expoxyed into a milled out hole in the end cap. 
I mounted the through-hole parts on a circuit board that is 0.9 W x 1.2 H. 
I used the 2N6660 because I had a bunch in my junk box. I would advise using something else. 
The frequency is about 7 Hz, 50% duty cycle.

These devices were designed for research purposes only. Walter makes no claims as to its efficacy and no recommendations regarding its use.