How about a picture or link to what you are looking to build. I have a black lab puppy, and have had some thoughts of adding some LEDs, but haven't settled on anything yet. Was kind of thinking of something I'll snap or clip-on to the collar when we go out at night (1 AM, 5 days a week before work!). Maybe a pendant the clips on next to the leash. Figuring on rechargeable batteries, and a solar charging station to keep weight and bulk down. Biggest problem is waterproofing, and a simple method of switch on/off and charging.