The Crystal Cave

Deep in the recesses of the Crystal Cave, you enter the final chamber of your long, arduous journey. The frigid, damp air is pain to your lungs but you pay it no heed. Your eyes are transfixed on the colourful natural crystal formations that you've been seeking. From the beginning of this expedition you knew you'd eventually locate these mysterious and coveted objects, however you did not expect them to be alive..... and breathing!

Greetings brave adventurers! I figured it's about time to do a post on a terrain modification I recently worked on. I can't remember where I got the idea for this piece, but if I do I'll mention it.

I wanted to modify a Dwarven Forge cavern "end" piece into one that has natural crystals growing up from the cracks in the floor and walls. Here's what the original, unmodified piece looked like before I hacked away at it:

"Unmodified" cavern piece

After procuring some "natural crystals" from eBay, it took a while to decide on the look of each crystal formation. Glueing these things together seemed like it would be pretty straight forward. I was sadly mistaken. The ends of most of the crystals are tapered to a rough point and were rather difficult to glue together. Even when they did, getting the light to pass through them efficiently was another challenge.

                            "Natural" crystals                                                   Crystals glued together (being held in place with  putty
                                                                                                     until the glue dries)

I didn't even use the crystal formation that's shown above in the final design. I tried glueing the formations together with one big blob of glue (I also tried silicone seal and hot glue) but the light didn't transmit well through all the "fingers" of the formation. After some experimentation, I found that cutting the base of the crystals at an angle with a dremel tool then glueing them together worked much better. This way, the light can propagate through the entire formation easier.

Next I needed to decide where I wanted to place the crystals on the piece, how many, and what each one looked like. I tried to make each formation look unique from the others as best I could to give it some variety. I made five formations because the LED's that worked best only came in red, green, blue, yellow, and white. Decisions can take some time because you only get one shot at doing it right. Once a hole is drilled - it's drilled baby! No goin' back. So after thinking about where I wanted to put the crystal formations on the piece, I finally made the measurements and drilled the holes from the bottom.

Crystal formation with many "fingers" (the grey hole in                                        A single crystal formation                      

            the back is for another one I added later)

                             Hole for the LED...                                                              ...to light the crystal formations on the wall

Five holes drilled successfully! I then glued the crystal formations in place using some cyanoacrylate (a.k.a. "Super Glue"). Of course after the glue had hardened I wasn't sure I liked how the single crystal turned out, so I decided to redo it by knocking it out with a screwdriver and hammer. Little did I realize how super "Super Glue" actually is. It came out after a good smack with the hammer, but took a good chunk of the Dwarven Forge flooring with it:

Cover your ears kiddies! A whole lotta cursin' goin on!

At least the piece of floor that snapped off came out in two pieces so I simply cleaned them up a bit and glued them back in place. Here's a picture with three of the five crystal formations in place:

Crystals are locked and loaded!

Okay, moving on..... The next part took a lot of tweaking and experimenting. I needed to get the LED's to breathe (i.e. slowly get brighter and dimmer as opposed to just blinking on and off). Not as easy as it sounds without using some sort of microprocessor or other complex circuitry. I wanted to use a simple 555 timer circuit for ease and compactness, so I did a web search for "555 breathing LED" and got many hits and YouTube links. Most of the schematics I found were similar so I picked one that worked for 5 volts and started soldering. I actually used an IC that had four 555 timers in one (to save on space) plus an additional single 555 timer for the fifth LED.

       IC with four 555's built in (with support circuitry)                                        Schematic diagram (for each LED)

The LED's I tried first were the standard surface mount type. I thought they'd be the best due to their small size, but as it turns out they just didn't have enough umph to completely light up the crystals when lit. So I did some experimenting with some high power mothers. As it turned out, they worked. Big time. I was amazed at their light intensity compared to the smaller ones.

        Very bright "power" LED's (on my test board)                                              Test light shining though a crystal

Next was the fun part (I mean - it's *all* fun but this was funner-er). Cavities in the bottom of the Dwarven Forge piece needed to be routed out so I could place the electronics and run the wires to the LED's.

       Wire routing for the LEDs (the blue putty is just                                   The bottom with all the circuitry installed
        (to hold the wires in place while the glue dries)

Once tested to be sure it still works, I filled the bottom up with air drying clay and let it harden overnight. The next day I sanded it flat and then re-glued the felt bottom back on.

           Bottom cavities refilled with clay (sanded flat)                                          Showing the power connector

The next step was to fill in the gaps between the crystals and the holes in the floor with a two part modeling epoxy putty called Green Stuff. This material also air hardens in about a day so it's pretty easy to work with. Once in place, a little creativeness is needed to mould the putty so it has the same (or at least similar) texture to the rest of the floor. Once it hardens, the putty needs to be painted to match the rest of the floor. This is the part I dislike the most because I think my painting skills aren't that great. Anyway, here's what it looks like:

            Green Stuff putty filling in the gaps                                               Here's one that's painted to match the floor

Once this was completed for all five crystal formations, the project was done. Simple, no? I couldn't get a still picture where all the crystals are lit up at the same time (due to each one having individual timing and flash rate), but here are some more photos of the finished piece and another video clip:

Hope you enjoyed this! Until next time, keep rollin' those criticals!

-Bob