Ultraviolet Light Pen

There are many things in the world around us that would look pretty cool under ultraviolet light, the only problem is they can't be seen, even though ultraviolet light comes straight from the sun, the cool effects of it are impossible to see because they are drowned out by the other light wavelengths of light. So as to help you open your eyes to the world of fluorescent material, I am going to teach you how to make a super efficient and super cool ultraviolet light pen for under $10!

Step 1 Parts and tools

All of the parts and tools necessary for building this project are availble at the Electronic Goldmine you will also need a knowledge of soldering , if you have never used electronic components before, never fear I will guide you through the process step by step.
tools

• a soldering iron
• a solder bulb (solder sucker or desoldering braid)
• a wire stripper
• solder
• a lighter or matches
• multimeter or a VOM
• hot glue gun
• your brain and your common sense!

Parts

• some very thin magent wire
• a small toroidal bead
• a NPN transistor
• a 1K resistor
• an ultraviolet LED
• a Bic pen
• an SPST switch
• a single AAA battery holder
• an AAA battery

Comments

[setsunafseiei]

A good practical use would be to detect fake money bill. It is really convenient because it's portable (or should be anyway). The moment the dollar bill doesn't feel right at your fingertips, use your pen, show it to the cashier, and ask for another bill. And if you're a good citizen, after getting a real one, take that fake one to a bank nearby.

[shizumadrive]

If you collect or sell vasaline glass it will glow under this light. And if you wander in the desert at night scorpions glow when show with UV.

I have some "doctor who sonic screwdriver" with uv light and it doesnt seem to use much more than a uv light and batteries.

[junits15]

Great idea I'll add that in the instructable :)

[sciman1]

could a joule thief be used to run, say...... a laser diode??

[junits15]

idk maybe

[Russian sniper]

thas so cool man
heres teh coolest uv pen xD

[wizzywoo]

wat r the dimensions of a ferrite coul please? thx

[junits15]

the demensions aren't too important important, (i don't even know them! :)) what is important is how many times you wind it, the more times you wind it the more juice it can suck from a battery. :)

[wizzywoo]

coil sorry

[whiskey]

How about getting a scented candle (with a glass container), give it to mom/spouse/girlfriend but ask them for the container later, fill it with hair gel + highlighter ink.  Put the UV LED on the gel and you get a cool lamp :D

Nice job btw, and keep us posted on how did they do that silicon gun sculpture XD

[codex653]

the highpitched noise is the coil resonating and yeah it does drive you nuts!! :)

[uldics]

1. A bit of misinformation. Dont call it pen, it is then understood as a thing to write with. Call it light, bulb, glow, flashlight whatever. 2. The noise from the thief is because your windings arent tight. Solution - rewind it as tight as you can, but remember not to scratch the wire coating isolation. Then if it isnt enough, dip it in some epoxy. Probably glue gun can solve it, not sure, probably it is too soft, probably it is right for the thing as it absorbs vibrations.

[junits15]

oh thanks for telling me, A quick note I've noticed that when I put a neodeminum magnet ner or on the windings the frequency of noise increases to a point that I can't near it which I thought was really cool, do you know why?

[uldics]

That is most probably cause the winding has a defined inductivity - it charges up and after that gives its energy back. That takes some time. When you add more magnetism around the windings and toroid, it probably speeds up this process, cause the toroid moves magnetic field faster. I dont know why exactly that happens physically, but I believe it is somehow like that. Though it is a bit of a surprise for me of such reactions. I would have believed that amplitude could change, but not frequency. If it gets sound level lower when adding neodymium around, probably it doesnt have to move so much magnetic energy around and can react faster from that? These two theories I have about it.

[Skip]

Sorry to hijack the Instructable, which is a nice idea. But Uldics, this is something new I haven't read about with joule thieves. They vibrate when the wrapping (on the toroid I assume) isn't tight enough? How is that possible?

[uldics]

That is possible because where is alternating current, there is changing magnetism. Changing magnetism makes magnetised stuff move. But that doesnt explain it, i know. I suppose the vibrations are due to eddy currents or something like that. No thing can be absolutely in accordance with theory. There is allways imperfections - materials not parallel with magnetic lines, windings not completely parallell and evenly spaced. Probably someone can explain it a bit less like a politician, but like a technician ... :)