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Need help building gift for girlfriend(LED necklace) Answered

So, Valentine's day is soon to be here. True, it is little early to be thinking about this, but the erly bird gets the early worm.

So, anyways, I came with a schematic for an LED based necklace. The whole idea is that it consists of a symmetrical shape split into two halves, each an individual necklace. One of those two contains an LED and the other a battery, and when the two are placed together, they complete the shape and the LED lights up, symbolic of her being my other half.

What I need help with is how can I build the contacts for the two halves and how do I actually build the two parts(what material to make them from, how to shape them, etc..)

Much appreciated. hanks in advance,
Usf

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NachoMahma (author)2008-12-01

. You could use small metal contacts and a strong magnet to hold the two pieces together.

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Actually two small magnets will do, nickel plated neodyium ones work and can be soldered to as can ferrite ones... I recently found a trinket in ASDA, a halloween glowing necklace that worked exactly like so...

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Usf (author)killerjackalope2008-12-08

To be perfectly honest with ye, I can't really make left from right of yer comment; I'm just a sixteen year-old high school student with no educational background in electrical engineering. My aim is not for the necklace parts to hold toghether, but just for the LED to glow when the two halves come into contact. Thanks alot though, I really appreciate the help.

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killerjackalope (author)Usf2008-12-08

Oh in that case it's dead easy, have a battery wherever, maybe in one half of the necklace piece and the led in the other side, the positive of the battery goes to a contact on one half of the piece, the positive of the LED goes to a contact on the other piece, the negative is put round the back of the necklace to make the chain, then embellish as necessary. If you want to make the necklace with a string or other material then two contacts per side, sorry for the jargon, most of it was the names of magnets and my weird vocabulary.

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Usf (author)killerjackalope2008-12-14

Thank ye very much, man. I think I should've made it slightly clearer in my request.

What ye described above is what I had in mind originally. I just needed advice on what to actually make/mold the necklace pieces out of. Otherwise, I've got everything else covered.

Again, thank ye soooo much for the help. I really appreciate it.

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killerjackalope (author)Usf2008-12-14

Anything that you're capable of working with, clay wouldn't be good because it couldn't be fired in the kiln without wrecking the components but I daresay an LED would survive a quick stint in the oven for FIMO or some such, maybe cast it in resin, have a dander around the arts and crafts shop....

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Kiteman (author)Usf2008-12-08

In one half, connect the "legs" of your LED to two small magnets, one at the top and one at the bottom of the part of the pendant's join.

In the other half, connect a small battery (a lithium coin cell, easily available on ebay or from watch repairers) to another pair of small magnets, set up to stick to the magnets in the first half.

Small neodymium magnets (again, ebay) are nickel-plated, so will conduct electricity. Stick the two halves together, and the LED will light (as long as it is the right way round - check your polarity as you Make).

Oh, and by age 12 you should have had enough basic science to be able to cope with a simple series circuit - it's the same circuit as a torch or LED throwie.

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Usf (author)Kiteman2008-12-14

Yeah, I wasn't familiar with the magnet names and therefore was oblivious as to what that meant and how it was of much help to me. It's just the jargon I was unfamiliar with. And yes, I am familiar with the basics of circuit building. I've built a click-on/off light pen. I'm not stupid. haha Thanks for the clarification. Actually makes more sense now. I was wondering how to solder the wires onto the magnets...

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Kiteman (author)Usf2008-12-14

Just don't get the magnets too hot, or they will demagnetise.

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Goodhart (author)2008-12-01

I was thinking that if you used copper colored magnet wire (that is, the wire they use for transformers, and electro-magnets), it would be chemically insulated rather then the thick plastic insulation used for normal wiring (even bell wire, is somewhat stiff) for the line; which could either be threaded through a gold colored? necklace or become the necklace itself, if it is the proper color and gauge.

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Usf (author)Goodhart2008-12-08

I was thinking I'd mold or sculpt an amulet of sort in which to embed all the wiring, battery, etc.. But yer idea of using the wire as the necklace itself might just work. But wouldn't the wire eventually become allergy inducing? or itchy, at the least? And how would the circuit go with the necklace as the wire? My initial plan was to fit the wiring, batteries and all inside the shape(amulet) with two bare contacts sticking out, where the current flows to light the LED. I was considering placing the LED in one of the halves, and the battery in the other. Thanks a bundle for yer help, I really do appreciate it. Also, if ye could help me figure out what material to use for the "amulet" and how to shape it and include the electronics. Thanks again.

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Goodhart (author)Usf2008-12-08

If there is the possibility of allergic reaction, one could still run the wire through a necklace, in such a way as to hide it , but not actually touch the skin. As for the amulet; there are a number of resins (clear to opaque) that can be found in various hardware store or craft stores.

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Goodhart (author)Goodhart2008-12-01

BTW: I like Nacho's connection idea. Many necklaces use a small rare earth magnet as the coupling device....

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Lithium Rain (author)2008-12-08

Can't help you with the electronics, but I must say that's a sweet idea.

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