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Best solar light, UV LED to use for UV Sun Jar Answered

I'm making a Sun Jar, but I want to swap out the normal white LED for a UV LED.

My plan is to spray the inside of the jar with invisible UV reactive paint, so when then LED comes out, the jar suddenly starts glowing a different color.

I tried making one tonight, but wasn't happy with the results.  I was using the black plastic Hampton Bay light from Home Depot - http://www.homedepot.com/webapp/wcs/stores/servlet/ProductDisplay?storeId=10051&productId=100068888&langId=-1&catalogId=10053&ci_sku=100068888&ci_src=14110944&cm_mmc=shopping-_-googlebase-_-D27X-_-100068888&locStoreNum=1002&marketID=48.  It's only powered by 1 AA battery, and the resulting glow from the LED was really dim.  I got no reaction at all from the UV reactive ground marking paint I was using in my test.

Any suggestions?

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kelseymh (author)2010-08-05

Most paints are opaque. You don't specify the particular brand you're using, but usually the UV-reactive stuff worked on reflection, not transmission.

TV's and fluorescent bulbs work because the phosphor coating on the glass is extremely thin, and the emission is isotropic. The glow from that CFL is only half the light being produced -- the rest is going back inside the tube!

Something like a "transparent" Luminol spray would work, but you'd have to keep reapplying the coating.

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mikejstein (author)kelseymh2010-08-05

I was looking at transparent UV paints, like the ones sold here. http://www.clearneon.com/cart.php?m=product_list&c=2 The problem is, I need to get my LED as bright as possible for that to work. I'm also open to using solar light that have multiple LEDs in them, and swapping all the LEDs for UV LEDs, but trial and error while buying multiple solar lights can get expensive, so I'm looking for some solar light recommendations.

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kelseymh (author)mikejstein2010-08-05

Ah! Thanks for the link (you might want to add it to the topic text). Yeah, those should work exactly the way you want on the glass jar.

For the lights, have you considered just building your own rather than hacking a pre-packaged garden light? Get a solar panel, build a "joule thief" circuit (Google will get you a schematic) for maximum efficiency, and wire up a bunch of UV LEDs to it in series.

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mikejstein (author)kelseymh2010-08-05

I'd much rather build my own, instead of buying all this extra plastic. I get how to build the super bright UV LED (There's already a really good instructible for it (https://www.instructables.com/id/Glowing-Alien-in-a-Jar/), but I don't know how to combine that with the only-on-at-dark I get from a Sun Jar.

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