Black Light From a Smart Phone

Have you ever wanted a black light to see stuff? But didn't want to pay an arm and a leg for one? Well I have good news then, but you probably already know because you clicked on this add. So if you just somehow randomly ended up on this page and didnt read the title, were going to make a black light using nothing besides 1)any smartphone, sharpies(markers), and scotch tape! I hope you like it as it is my first Instructable, and if you do please vote for me in the Phone Contest! Thanks!

What you need;

1) A smartphone, any one will do for this as long as it has a flash light on it. I'm using an Iphone 6.

2) Scotch tape, I guess any clear tape will work though.

3) Either black and purple sharpies or markers. I'm using a blue sharpie and a purple marker.

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Step 1: Make the First Layer

Put the first piece of tape over the light on your phone and color it BLUE. Tip; make sure there is noting under the tape and the tape is flat against the phone.

Step 2: Add the Next Two Layers.

Do the same thing you did with the blue tape, but this time with purple for the next TWO pieces of tape.

Step 3: Test the Light!!!!

Now you have a blacklight made out of a few things and your phone you can make in just a few minutes! Plus you can carry it around in your pocket and whenever you want a normal light again, just take the tape off!

Thank you, and if you like it please vote for me in the Phone Contest!!!

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    8 Discussions


    4 years ago on Introduction

    You are basically making a "Wood's Glass" filter just like the glass on an incandescent Black Light, light bulb. It will work but not much power will be emitted at the ultraviolet wavelength from most white LEDs used for cell phone flashes. You need energy in the 100nm to 400nm wavelengths and most will be in the 300nm to 400nm.

    I'm going to give it a try, I'm betting the markers will make a pretty big difference.


    4 years ago on Introduction

    I'm pretty sure this is fake. You cant put blue/purple tape on a white led to make it shine UV light. You need a UV LED to project UV light. What you did will just project regular blue light.


    4 years ago on Introduction

    Can someone please explain how this works? Isn't smartphone flash an LED that emits white visible light with no UV emision?

    1 reply