Hi Shanti,

First let me apologize for all the crap on whether you're what you say you are or not - such just degrades a forum and quite frankly, it's so extremely irrelevant - although I smiled at the morning sickness comment as well, score one for raising the mood

What is relevant, is that you're a person with a question and if we can be of assistance, that's what we should care about (or else shut the pie hole)!

My Granddaughter sells fairy jewelry, etc at the local farmers market and wants to add some "fairylands" with lights, battery operated strings with anywhere from 6 to 12 led lights on them.

To keep it "cost effective", I was wondering if she could buy strings like this, and extra battery boxes and maybe get 4 or 5 sets out of one string....or am I totally off base on this.

Did you consider just buying the LEDs that you want from eg BestHongKong http://www.besthongkong.com/
I'm not sure exactly what type of LEDs you're after, but maybe you could even get the finished product directly from DealExtreme, which has free world wide shipping and extremely low prices on such nick nack - you could probably get lots of other stuff that she could sell as well. h0t1tp://www.dx.com/s/led string lights

Just make sure you order less each time, than what tax and custom might punish you for.
Oh, and order at least a month before you need it - sometimes they're quick, but I have had to wait up to 3 months on occasions - 3 to 4 weeks average is probably a reasonably estimate.

I have read and watched a few youtubes on wiring leds, which I'm pretty sure we can do....but the schematics as to volts, resisters, etc give me morning sickness....

These sets are 40 leds running off 3 double AA batteries....what would 6 or 8 or 10 or 12 require?
And could they be wired about an inch apart?

I probably have more questions, but first I just want to know if the idea is feasible

Not knowing your soldering skills or if you're set up with tools to do it, I think my best advice is to get some ready made lights from DX.
If you're a hawk at soldering and have the tools needed, perhaps make them from the ground up - you'll need a battery box for each, whether you buy long strings or build the strings yourself and I'm sure you can find this at DX as well.

The schematics for a simple LED string with resistors to limit current and how to calculate it, shouldn't be too hard to learn - 2..3 posts tops I'd guess, it's not like you need to know all aspects of electronics - just what an LED, a battery and a resistor looks like in schematic form and their physical appearance, plus a very simple calculation that's only needed once for each variation of the strings - if they're all the same, once will do and I have a sneaking suspicion, that you may be able to get someone to do it for you.

 

LEDs, 555s, Flashers, and Light Chasers