DustHand wrote:The more stuff like this you fabricate, the more likely it is to fail in some capacity.
Alternatively, if something you made fails, you know how to fix it. Manufacturer's promises are lies (unless they use concrete units/standards, and those are backed by independent testing.) "Waterproof" means nothing unless it's "waterproof to 3m", or better, an Ingress Protection Rating (IP-code) that's been verified.
Consider also that things like connectors and switches can be prone to failure from dust. Sliding connectors (e.g. RJ-45 or PowerPole) are better than pin connectors (DB-9, etc.) and pressure connectors (e.g. Apple laptop magnetic power coupler).
But good luck with that decision.
DustHand wrote:To get or have made a faux fur coat. Remove the lining, and cut tiny holes the size of the LED in the backing material.
I made a similar, also fake-fur LED coat
. I cut the lining at the bottom all the way around and slid the electronics up inside. I have a string of custom boards with RGB LED's on short leads off them (5 LED's per board; 10 boards). The LED's use 0.050"-spaced ribbon cable that matches the pin spacing on the LED's; I trimmed the LED leads short, soldered the ribbon cable on, then bent the cable at 90° and potted the connection with JB Weld. The boards are interconnected with waterproof Category 5 cable, and the individual boards were assembled, all tested, then sprayed with "conformal coating" (a.k.a. clear acrylic coating) and potted with silicone caulk.
The boards are sewn to the inside of the coat with fishing line (nylon string, 5 pound capacity) like you'd sew on buttons. I cut small slits to pop the LED's through then held them in place with hot glue.
I learned that although the boards are thin, I can still feel them inside the coat, and it makes for lumps on the outside. Not too bad, and also considering the coat is a little small for me.
For batteries, I have an 8-pack of AA batteries for a total capacity of about 24 watt-hours (2500mAH * 1.2V * 8 batteries). The controller uses a 7805 linear regulator for the logic control and an adjustable switching regulator for the LED power. I tuned the switching regulator to the minimum voltage that would still produce a consistent white (too little, and the blue and green LED's aren't as bright, particularly at the end of the string.) When I run all 50 LED's at full white (e.g. 150 LED emitters at 20mA each = 3 amps) the power draw at the battery is only around 1 amp or so. Most patterns I run average around 200mA from the battery for about a 10-15 hour run time.
DustHand wrote:Looks like I am going with some small lead-acid cells. They don't recharge as fast, but they are CHEAP compared to NiMH, Li-Ion, or NiCd. I have one on order to begin testing how many I will need per night.
Don't forget to consider primary batteries. If you're going to use this a LOT, then rechargeables are the way to go, but if they're only getting used for Burning Man, then a pack of D-cells may suit you well. Alkaline D-cells have a 10 amp-hour capacity although you can only discharge them up to about 1 amp. I don't think you'll be able to get to 120 watts with any battery pack — a 8AH 12V sealed lead-acid battery would be completely flat in less than 30 minutes and that weighs 6 pounds.