Introduction: Phone Light to UV Light Hack!! (Works With Other Lights Too!!)
Hello Youtubes and Instructaganders it is I TrollFaceTheMan, and today I'm going to show a neat trick to hack almost any stranded L.E.D. Light into a makeshift UV light. Also in this video I'm going to try it with an incandescent light and see how it compares.
First thing is first though, when we do this we actually are not creating any U.V. Light at all, but instead are creating a filter to separate out a lot of the visible light to help us see the UV effects better. Because of this, the U.V. Light you get out of the filtered flashlights is nowhere near as powerful as if you were to actually have a specialized UV bulb. But that doesn't stop it from lighting up certain objects like Christmas lights, however sadly on white it doesn't work so strongly as with regular UV. But more on that later...
So what do we need..? Well in reality all we need is Some clear tape, two permanent markers, one dark Purple and one dark blue. And a light to do this on, the one you probably have on your phone will do just fine and is the one I'm going to demonstrate this on. The extra lights I have here are just for fun, and the highlighters are there to demonstrate the lights UV properties, but aren't actually needed to create this UV light.
Step 1: Making the Filter
Alright so to actually get started take a small piece of clear tape and cover the light you wish to use for this completely. If your doing on a phone like me, make sure you only cover the light and not the camera lens. And if your doing it on a flashlight you might need multiple pieces of tape to cover it.
After you put the tape on it use the blue permanent marker to completely cover the tape with blue, over larger area such as flashlights this might be difficult in which case holding the marker at a strong angle can help the ink get around. But you'll probably never get it perfect.
Step 2: Continuing the Filter
Anyways after that's done and dried, do another complete layer of tape and color it blue once again with the permanent marker. After this is done, do one more layer of tape but this time color it completely purple with the purple permanent marker. And that's it, you have a makeshift UV light.
Step 3: Demo of the Light!
So like I said before, we're not creating UV light. We are filtering out a lot of the visible light from the L.E.D. Or Light Emitting Diode's light spectrum. What this leaves us with is a color of light that is actually invisible to us, or certain levels of it are verging on our see able color spectrum.
Almost like how we can't hear sounds that are too high like a dog whistle or too low like infrasounds, we can't see colors waves that are too high frequency like Uv's or too low like infrared.
So the reason why Uv light make things glow isn't actually that it's any brighter in that location than anywhere else in the vicinity, it's just that it's the only light that you can visibly perceive as light. The reason those items appear to glow is because they contain things know as phosphors, when UV light interacts with phosphors it loses energy in the form of heat. The loss of energy slows down the frequency of the UV waves enough to push them onto the visible light spectrum and wallah, perceivable light.
This light makes the object seem to glow intensely, though in reality it's not as bright as the UV light all around it. But we don't see this extremely bright UV light so we don't care, it looks cool and that's what matters!!
So the only problem with the Uv filter on phones is the phones LED can get hot and melt through the tape, if you do use it. Do so sparingly and for maybe only a minute at a time, it shouldn't catch fire or nothing but if it melts you have to replace it which is a pain.
Step 4: Other Lights
I also tested a Five light LED and a normal incandescent flashlight, here were the results.
Incandescent- Preformed the worst by far, however still gave us some weak UV action. This light seemed to of had a lot of Orange/Reddish light pass through our makeshift filter dampening the effect. (Not recommended for this project.)
5 Light, Ultra Bright LED Headlamp- Worked the best, but probably no surprise seeing as it's just a stronger form of the light on my phone. (Recommended!!)
Phone Light- Preformed second best, only to be Trumped by the Headset which is no surprise seeing as the headset is just a brighter version of the light. (Recommended!!)
Thanks for reading this Instrucatable and please watch the video for some extra content not show here, and please hit the "Like" and "Subscribe" buttons if you enjoyed it on YouTube. And the "Favorite" and "Follow" buttons if you like it on Instructables!! Thanks so much for reading/Watching!! and Bye!!
(Side note: To return your light to normal simply remove the layers of colored tape.)

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5 Comments
6 years ago
See link here http://www.diyphysics.com/wp-content/uploads/2012/...
Just
because it doesn't show up on the bill doesn't mean it's not UV, it
just means it's a higher spectrum UV 395-400nm that we can see as part
of our visible spectrum and because of that we don't really see much or
any reactivity as it's washed out by visible light.
7 years ago on Introduction
You know this only make purple colored light and not UV light, right?
Reply 7 years ago on Introduction
Your photo might also proof that you have fake 5$ bill heheheh
just kidding you're absolutely right
Reply 7 years ago on Introduction
Once again Purple light is Between 400-440nm and is non-reactive to Phosphors, UV is Between 100-400nm. You can clearly see the light Lighting up the highlighters which means it's not just purple light, but UV light... Otherwise simple "Purple Light" would have no reaction on it...
Reply 7 years ago on Introduction
You are Incorrect, it makes a filter separating out a lot of visible light and leaving behind the UV spectrum relatively untouched, if you knew about light you would know that LED's actually do have UV radiation to them but it's weak.
UV light is light in Between the spectrum of of 100nm-400nm and as you can see a standard Cool White LED had Radiation levels between >300nm-400nm which is UV light, while visible Purple light is only 400nm-440nm and non-UV meaning if you filter out most of the visible light you're left with a UV light albeit it's week in comparison to an specialized UV light, but it's definitely not just a "Purple Light" as you try to claim.
I would suggest doing some research next time before trying to tell people what they "Should Know." Especially seeing as I already mentioned it's not as powerful as a specialized UV light, especially on whites as the UV radiation levels are weak. But it is surely is not just a "Purple Light..."
Thanks and have a nice day.