Mood Crystal Light

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Intro: Mood Crystal Light

How to make a moody crystal light for under $10!

It is time to make good use of the Selenite crystal that has been sitting in my room for ages. I brought the crystal from a collection shop while ago on holiday in Devon for $2. You don't have to use the selenite crystal for this project, you can use any kind of crystal that is transparent or cloudy.

BTW, I am British, I have to use the American currency symbol because instructable dose not like the British currency symbol.

STEP 1: What You Will Need for the Project

Nothing really expensive, other than the RGB LED's and the crystal, they can be quite expensive in some place.

  • Double AA battery holder
  • Two AA batteries
  • A switch
  • A small piece of veroboard
  • Some wires
  • Transparent or cloudy crystal
  • A project box (I ran out of them, so I have to use a container)
  • RGB LED's (see next step)

STEP 2: About the RGB LED's

The RGB LED's are not very easy to fine and you are unlikely to fine them in Radio Shack, Maplin, or in other little electronic stores. The best place to buy the RGB LED's is on the internet, the internet has everything. :-)

I brought 50 RGB LED's from this ebay store for $9, you can buy the LED's from a different seller.

In this project, I used three LED's, and I am going to use the rest for my other project. You can use much LED's as you want for your project,


The RGB LED's has a starting voltage at 3v, so you don't need to use resistors if you are going to power the LED's at 3v.

Also the RGB LED's tends to flicker or 'reset' when they are put in parallel together and being controlled by one resistor. It is a good idea to give every LED's their own resistor to prevent flickering. My LED's did not flicker bad, so I left them without resistor.

STEP 3: Make a Hole in Top of the Container

I marked out where I am going to put the crystal and grabbed my dremel with a cutting head and started cutting out a hole on the container.

While I was cutting, some bits of plastic shattered and when flying everywhere, it is a good thing I was wearing goggles...

After I had done cutting and filed away the blur bits, I sprayed the container glossy black to give it a more stylish look.

Then, I made a mistake, I forgot to make a hole on the side of the container for the switch after I had sprayed the container black. So I make a hole for the switch and resprayed the whole container again because some paint came off.

STEP 4: Build the Circuit

I soldered the RGB LEDs in parallel onto the veroboard. Soldered the switch between the positive output from the batteries and the positive side of the LED's. Then soldered the ground side of the LED's to the negative wire of the battery pack. It's simple.

You can do this without doing any soldering, just twist the wires together and hold the wires together with tape or glue.
Like all other LED's, RGB LED's have polarity and you can determine the polarity by the length of the leads.
  • If one lead is long, it is the positive side of the LED or the anode.
  • If the other lead is short, it is the negative side of the LED, or the cathode.
If you are going to power the RGB LED's higher than 3v, then you will need a resistor to protect the LED from too much power flowing through it.

Most RGB LED's consume 30mA at 3v, so here is a list of calculated specs on what resistor you should use at different voltages.

  • 3v - (don't need to use a resistor)
  • 4.5v - 56 ohm resistor (color code - green/blue/black)
  • 6v - 100 ohm resistor (color code - brown/black/brown)
  • 7.5 - 150 ohm resistor (color code - brown/green/brown)
  • 9v - 220 ohm resistor (color code - red/red/brown)
  • 12v - 330 ohm resistor (color code - orange/orange/brown)

Also, you don't have to use an exact resistor from the specs, you can use a resistor that has similar ratings to the recommend ratings.

STEP 5: Attach the LED's to the Crystal

I did in a rather simple and crude method. I wrapped paper around the crystal and taped it down, leaving some space on the bottom of the crystal to put the LED's in.

Then I taped the LED's on the bottom of the crystal.

STEP 6: Put Everything in the Container

Then put everything in the container (or the project box). I glued the battery pack and the switch in place, but I left the crystal lose, it should not cause too much problem.

STEP 7: Enjoy...

When you first switch it on, it will glow in this first sequence, red, green and blue... That is why the color changing LED's are called RGB.

Then after the first sequence, because all the LED's have slightly different timing on when to change color, it will produce a much wider range of unique colors. I had the crystal glowing white once, but that happens very rarely.

25 Comments

Nice and simple! :)

You should mention that these are autochange RGB. most RGB (such as the ones you get off digikey) do not have the built in circuit that causes the color change. RGB LED is a LED w a red, green and blue LED glued under a single lense (speaking most simply) and one lead in common. Changing the voltage to the other leads is what gives the different colors
neat this is an easy experiment and would be a cool light
Cool. You can get a similar effect with a piece of plexiglass. Once it's sanded and roughed up it looks kind of cool. The crystal does look like it would be sharper looking.
wow you're lucky, my radioshack charges $3 for one blue LED
were can u get that crystal thing and if u no how much that would begreat. i really like this ible it quick easy but on others it say u needsome sort of processor for the rgb is that true or will it still work normal
If anyone's thinking of building this, then I found a 7" Selenite crystal for just £2.95 (+£2.40 shipping).

http://www.crystalreflection.co.uk/HFSE4204-selenite.html
If you are using Fire Fox just change the spelling to British and forget instructables spelling.
Buy from ebay, :-) much cheaper than those little rip-off stores.
i have found radioshach has ridiculous prices for components but for kits and electronic devises such as headphones microphones headphones etrc.
Nice. That is really trippy.
One tiny caveat.....some places call any LED that can change color a RGB or RBG, even those that must have current reversed to get two of the three colors, with the third being low amperage ac.

Otherwise, I like the application. :-) (if I could find my crystal I have that glows under UV lights I could add a few UV LEDs to make it really spooky looking in the dark ;-)
A crystal what glows under UV light? Cool! What is it call??
I got it YEARS ago (33-36) and so am not sure. I thought it was called Pennsylvanianite, or something like that, but I can't find a reference to it online or anywhere. I thought it was native to my area, but then I am not sure where we were (school trip) that had the crystal for sale. I have been looking for SOME kind of reference to it for over 10 years now......so far, I am drawing a blank....it glows under UV, very much like the mineral Powellite, but it doesn't LOOK like it
Hmm, I tried to do some research as well, no positive results, just lots of junk on google. :-( I got a feeling the crystal might be a fake, because I seen some sites (can't remember what is it called) selling greenish 'crystal' that glows under UV, but I later found it is made from plastic with UV reactive chemicals.
This was sold at a museum, or other such place while our class (don't remember the grade) was on a field trip. I thought it was so COOL looking in the black light room, but was crushed when I could no longer find it, about a year or so ago....
Very nice, I think I'd prefer the ability to control the colour but the slow fading is a simple option. Where were you in Devon? I'm guessing south coast, given you bought a rock crystal from a souvenir shop...
It would be nice to control the LED's, but I don't know about microcontrollers yet... :-) Yes, I got the crystal on the south coast of Devon from a souvenir shop, how did you know that?
I used to live on the south coast, selling stuff like that is exactly the sort of thing they are good at. On the north coast you'd probably be surfing or getting quaint countryside stuff, and no-one goes on holiday to the centre of the county except to go to Dartmoor where you'd probably get a nice decorative piece of radioactive granite :) I meant Plymouth, Torbay/Paignton, Dawlish, Exmouth/Sidmouth (if you remember)?
Hmm, I have not been to the north coast yet. And you can get radioactive rocks from there? cool!
cool i think the shape of the crystal works well for this :)
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