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Can led light be activaded by puting things* close to each other? Answered

can led light be activated on close up and light off on moving upart.(maybe magnet or some other options)
Looking for distance about 1" for light on.Have room size of a pen or a lighter for components.
...and 1 more question:How much heat or static you need for led light to work?
Thank you all in advance and sorry about eng.:( 
 

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user
RavingMadStudios (author)2009-11-25

Hmm... This is the second time in a couple of days that a question has come up that made me immediately think "Magnetic Reed Switch". I think a normally-open magnetic reed switch will solve your problem. You might need a more powerful magnet than the one that comes with the switch to get your 1" range to work consistently, but that shouldn't be hard to come by.

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user

I was actually thinking a Hall-effect sensor.  A reed switch would require too strong a magnet at that distance to also be compact.

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user

I can see your point. The tradeoff, I think, would be a slightly more complicated circuit and possibly having to take polarity into account. Other than that, makes sense to me.

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user
F1lya (author)RavingMadStudios2009-11-25

were i can buy Magnetic Reed Switch?

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RavingMadStudios (author)F1lya2009-11-25

Your best bet is probably either online (try digikey.com or eBay) or at a place like Radio Shack. They are used as window sensors in home security systems, so you may even be able to pick one up from a local locksmith or security company.

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