Create Wonderful Light Painting Art Using A Cold Cathode

relative field strength (by { tcb })The following article is a guest post by Dana Maltby a.k.a. Twin Cities Brightest a.k.a { tcb } a Light Painting Art Performer.

Greetings again from Minnesota where it’s getting cold again. Below freezing last night, brrrrr!! But there ain’t no rest for the wicked, so let's get back into some light painting techniques. This time I would like to talk a bit about Cold Cathodes.

A cold cathode is a tube of light that has a similar look to neon lights. It is brighter than a glow stick, and you can attach an on/off switch making them much more versatile in the field. You can find different kinds of these cold cathode tubes. They can be found at auto part stores, for in car light accents and under car lighting.

Getting a Cold Cathode

swinging (by { tcb })

I have found that the internet is the best and least expensive source for cold cathode lights. A good search is “cold cathode computer case lighting”, I like to get the brand Logisys. An even better search would be “logisys cold cathode computer case lighting”.

The first way I learned how to do this I bought the light from the auto parts store, and with help from this tutorial on the Flickr group Light Junkies, I was able to make a working “light saber”. So big thanks to Tdub303 for starting the tutorial and being such a huge influence for me.

Getting The Parts

(Other than the cathode, of course)

Power: There are a few ways to hook up cathodes to batteries. Most cathode lights are 12 volts, so in battery terms that is 8 AA batteries or one 9v battery and two AA’s. Buying one battery holder for 8 AA’s is the simplest, and doing the 9v and 2 AA’s is the most efficient and lightest.

Here are the two options side by side:

step 9 (by { tcb }) cold cathode circuit (by { tcb })

Inverters: A cold cathode runs on a higher voltage than 12V. It also runs on AC. I am not going to bore you with the specs, but you're gonna need an inverter (that's the box on the images above).

Inverters get 12V on one side and pump a nice ton of V on the other, try not to touch the wires that come out of the "other end" of the inverter.

Switch: You're gonna need a switch to turn the cathode on and off (For the same reasons you want a switch on your orb string). You need the kinda switch that has two connectors.

Completing The Assembly - A Step By Step Guide To Bomb Dismantling

To set up a cathode from the internet with an inverter, take the light out of the package.

step 2 (by { tcb })

Get a feel for what you got, (it can seem overwhelming, but take it one step at a time.)

Once you see that the light plugs into one side of the inverter (the box), you see that the wire part plugs into the other side. You only need the RED and BLACK that come directly out of the box. I cut them with as much wire as I can get, about 12 inches. (It's just better and easier to work with some slack till you know what you're doing)

step 5 (by { tcb })

Cut the extra wire and stuff off, leaving a red and black coming out of the inverter.

step 6 (by { tcb })

The battery holder with a connector thing. I think some holders have wires already attached to them. The point is you need wires coming off of the holder for 8 AA's.

step 6.5 (by { tcb })

Here comes the bomb dismantling part. I just went RED to RED, with the switch on the RED side. Just twist and solder the blacks together, no switch needed on that side. There should be two prongs on the switch or remember when you are buying the switch that it should look like you can stick wires into TWO different prongs, whatever they look like.

step 7 (by { tcb })

Disconnected it to solder the wires together. It's only 3 points to solder, two on the switch, and one to attach the two blacks to one another directly.

step 7.5 (by { tcb })

Test it to be sure it lights up before you attach to a stick or whatever.

step 9 (by { tcb })

Luckily, some car lights have built in inverters, so the model below was even easier to assemble. Just cut off the car adapter plug, put a connector on the battery pack, added a switch into the circuit, and touched the wires to make sure it worked (you can’t really get shocked to bad, but still try not to).

If you're not getting one of those lights, make sure you get a "kit" it will have both a cathode and an inverter.

it's fresh and new! (by { tcb })

With the LOGISYS brand, you can plug in two different lights into one inverter box. I think using this brand exclusively for now is a good idea for me. That way everything is interchangeable, and theoretically, if anything breaks I can just plug a new one in and be good to go.

Some Cathode Resources:

Blue, 4$ (came with two lights)

The yellow is more, but I just had to have a yellow $8

Big bunch of cathodes I use

Other Random Notes:

  • If you get stuck go to the light junkies tutorial, or contact me directly on flickr and I’ll help you solve the problem personally, have fun, cathodes rule!!!
  • Cathodes seem to lose power in the cold, so if you live somewhere like me, where it gets below freezing, you may not be able to use this in the bitter cold.
  • Some colors are brighter than others.
  • Cathodes are fragile, I have broken at least 10 since the beginning.

zimuth (by { tcb })

 

http://www.flickr.com/photos/30561958@N02/3185531505/

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Comments

Thanks so much for the info

  • December 14, 2009
  • Wilson

Thanks so much for the info gonna take my pc apart and take the cathodes from it and try this out.

9V + 2 AAs?

  • December 15, 2009
  • Anonymous

"Most efficient"? Say what?

Ever see that warning that says "don't mix batteries" in various pieces of gear? 9V batteries have, at best, the equivalent of 6 AAAA (yes, that's _Quad_-A) cells in them, and at typical commercial retail an alkaline one will wind up costing you at least $3 for 3 watt-hours.

That means they cost $3000 per kilowatt-hour, making them a very poor choice from the standpoint of economy.

And then you're stacking them with 2 AAs? That's "mixing batteries" there. When the 9V runs down first (as it will) the higher capacity of the 2 AAs will start getting wasted.

Dollar stores will sell four zinc-acid AAs for a buck, or two alkaline AAs for the same. Eight of the latter will cost $4.00 and last substantially longer than stacking a 9V with two AAs.

Correction to my earlier comment

  • December 15, 2009
  • Anonymous

"$3000 per kilowatt-hour" was an error. The correct figure is approximately $1000 per kilowatt-hour. Sorry.

thanks for the review.

Hey there anonymous,

thanks for taking the time to read through the article.

it looks like during the several drafts i wrote i forgot to include the part about me not being an electrician. I didn't want this article to make anyone scared about mixing batteries or wasting money on parts and supplies.

i think perhaps you could have sounded a little nicer about it but since they havn't invented a sarcasm typeface i'll just hope i was reading yours wrong.

this is how i make cathode lights for cheap, and the two AA and one 9v method seems to work very well so far. It is much lighter and easier to handle because of the weight difference as well. But by all means, use 8 AA's too. In my case i usually bash the light on something while waving it around, drop it in water, leave it on by accident, etc, so they get re-made and a bit differently each time.

these are some ideas others had.

http://www.flickr.com/photos/mikeleary83/2884599233/

http://www.flickr.com/photos/adriank-/2882337221/

http://www.flickr.com/photos/gbooth97/2904576238/

http://www.flickr.com/photos/35520515@N06/3502182898/

http://www.flickr.com/photos/55125/3992383110/

as you can see, everyone does it differently but the fact is you won't care if your wasting some batteries once you make a couple of great photos.

dear anonymous, you should try to make a cathode wand and send me the pics, that would be awesome.

Added questions

  • December 22, 2009
  • Rick

Can you use this for stop motion?

thanks!

Can't wait to experiment with this. :)

Batteries...

seriously guys... RECHARGEABLE BATTERIES

go to your local store and get Sanyo Eneloops. They will last you for quite a while.

 

Costco sells them.

Additional Cathode Source

An old DIY Video by "KipKay" found on YouTube revealed that you can also get a cathode light (and a nice tutorial on how to set it up, also) from an old flatbed scanner! Put that thing to use! :)

Light Painting

Great post and idea. I am going to get started right away. -Dave Z.

Step Light

Really beautiful and stylish

inverters

  • June 4, 2010
  • Laser Lew

could you please tell me what kind of inverter(s) I need for cold cathode light wand

Other colors

  • July 21, 2010
  • Randy

Using just a white bulb and a buddy to hold colored plexiglass, celephane or other filters over the camera lens during exposure can add a wide varitety of color not possible with just colored tubes.  This is a trick I used to use with long exposure flash photots of buildings.  The building would look like it was lit with many colored floodlights, but in reality it was a single strobe and a gel filter sample pack with a different filter used for each strobe exposure.

hey

  • September 15, 2010
  • andrew

i love this tutorial on color cathodes =). thanks for sharing this. one question though. i would like these to use for drawing but i also have this idea of putting one behind me and making shadows of my body, so what size should i use? or should i just get 2 because i can easily afford that with how cheap these are but i would like to save as much money as possible.

Thanks again!

~Andrew~

Thanks For The Shout Out TCB

Hello!

I was wondering why i get so many hits on my photos of the light want i created... hahaha and here is why...! Thanks TCB. Love yah man!

PS! if you want more tutorials and photos, check out my photo stream!

http://www.flickr.com/photos/55125/

THANKS!

-55125

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