Project : Atomic Sun

Progress and innovation let us build a world that departs increasingly from the environment for which we evolved. To resolve the mismatch between our genetic disposition and the world we build, we must either adapt our environment or adapt ourselves. Winters are pretty dark up here, some days I'm not sure the sun even rises. So, I built this lamp. Its on a timer, and functions to keep the circadian rhythm intact.

These are instructions for building a very bright lamp with 20 bulbs and a truncated icosahedral core. Development set me back about $120 total ( bulbs included ), but you should be able to build this for as little as $40 not including the light-bulbs or cost of plastic.

Edit : This was printed on a MakerBot Cupcake which costs $850 now. If you can't afford one, your local hackerspace may have one, but they are difficult to get working. Plastic costs 0.024/gram. $34 is a lower bound on the costs, excluding the printed parts and bulbs. My costs were higher because of waste. The sockets are the only part you can't scavenge or print. You could print those as well, if you figure out how to do the wiring. I would have used LED bulbs if I could have afforded them at the time.

Parts :

• 1 × pentagonal hook http://www.thingiverse.com/thing:6117 "p hook 3"
• 12 × basic pentagons http://www.thingiverse.com/thing:5961 "p" ( pentagon )
• 20 × hexagonal lamp brackets http://www.thingiverse.com/thing:6055
• 20 × lamp sockets Cooper Wiring 732-BOX Sign/Scoreboard Lampholder
• 20 × low wattage CFL bulbs, like these
• 1 × electrical plug SA440-BKCC10 15A black nonpolar plug or equivalent ( any plug will do )
• 16 feet of 12 to 16 gauge lamp cord
• 6 feet of rope or chain
• 2 × (optional) rope holder thing http://www.thingiverse.com/thing:6149

Materials:

• electrical tape
• super-glue ( I used Gorilla brand )

Tools:

• Pliers
• 3D printer
• razor knife
• wire cutters
• wire strippers
• Phillip's head screwdriver

Assembly:

First print out the indicated quantity of all printed parts.

More detailed assembly instructions for the lamp socket brackets can be found on the thingiverse page. Trim the bracket until the black socket rests flush inside. This is important, since we need the hexagonal cover plate to bond to both the bracket and the socket for a good fit.

The orientation of the socket within the bracket will matter later. The socket has a wide ridge. Align this ridge with a side of the bracket for 10 pieces. Align the ridge with a corner of the bracket for the other 10. Aligning randomly also works, as long as you don't align all sockets so that the wide parts face a side.

Print out 12 pentagonal pieces. All pieces have extra plastic to stabilize the hinge while printing. This can be removed easily with a razor knife.

Perform a test assembly with just the hexagonal pieces. Leave out the pentagons for now since they are hard to remove once assembled. Ensure that all light sockets fit properly and don't collide. You may have to experiment, rotating and swapping between pieces, to get everything to fit well. If all else fails you can tap apart one of the brackets and re-orient it.

Carefully unfold your test assembly into an as-linear-as-possible planar arrangement like below. The exact arrangement doesn't really matter, just so long as there isn't too much branching.

The lamp sockets clip onto 12 to 14 gauge electrical wire. The only 12 gauge wire I could find had too thick of insulation to work with these sockets. I used 16 gauge wire instead, which just barely works. Using scissors or a knife, separate one end of the lamp cord. Protect the ends with electrical tape. Starting at the far end, clamp the sockets to the cable in turn. The sockets are difficult to close, so I had to use pliers to get enough force.

Before you get excited and attach the plug to test everything, slide on the pentagonal hook piece over the cable. The top of the printed piece should be facing away from the assembly, toward the plug. I neglected to do this, and had to dis-assemble my plug to add this piece.

To assemble the plug, use needle-nose pliers to remove the orange stopper from the front of the plug. Remove the prongs. Thread the lamp cord through. Split and strip about 13mm from the end of each wire. Wrap the exposed wire around the bolts attached to the prongs, and tighten the bolts well. Replace the prongs and stopper.

Test each of your sockets. Turn everything over and plug in some lightbulbs. I did it the dangerous way by adding and removing bulbs ( I only had 2 at the time ) while the thing was plugged in. People that don't want to die should un-plug the setup while moving the bulbs. Better yet, order the bulbs with the rest of your parts and put them all in at once to test.

The next step is tricky. Unplug the setup and remove the bulbs. Turn over the setup. You are going to need to fold the pieces back into the polyhedral shape. The lamp cord is inflexible and resists folding, but bending each joint beforehand helps. Adding in the pentagons while folding provides more stability. As the polyhedron becomes more complete, it becomes more difficult to add pieces. If you're having trouble getting a hinge to mate, pry up slightly the side that is already in the polyhedron. The hinges come together more easily if pushed together from the side, rather than if pushed down from above.

When it was all done, the compressed cable overpowered the super-glue on a couple brackets, thankfully this mistake is easily fixed with more super-glue and some patience. You should end up with an object that looks more than a little bit like the detonation mechanism for an atomic bomb. The final assembly is very strong and the hinges will hold together without additional glue.

The last piece you'll insert is the one that contains the power cord and the rope or chain for hanging the lamp. I would attach rope or chain before you add this piece. Don't use polypropylene rope like I did, it doesn't hold knots. A chain would look nicer anyway.

Thats it. You're done. Hang the lamp somewhere, insert bulbs, and power up your own miniature sun.

Drop-Day 2010 Tech

I figured I'd start writing this up on the return flight from Drop Day, so I'm typing here at an odd, cramped, angle from my flight back from LA to Pittsburgh.

Drop-Day was a fine production, a victory for both hobbyist physical computing, and the forces of democratic freedom. I was impressed with the stark giant white cube dance floor with the, as Biff describes, lovecraftian monolith as a centerpiece. Something about the smaller size and the fog machine made people actually want to dance this year. The sensory rooms were excellent, although some of the code running the party never got off the ground. There is something uniquely appealing about a party that crashes, and requires rewriting of computer code and recompiliation on the fly. In addition to projected visuals ( Kanada, Perceptron, Cortex, Live and recorded video feeds, and other trippy renderings ), we had a few Alumni constructed blinkylights. Keegan completed a most excellent glowing octahedron, Suresh completed a rather nice modification of a commercial lamp, and I constructed several more pairs of goggles. I have spent most of my time travelling ( and very little sleeping ) this weekend, and it was well worth it. However, I doubt I'll be traveling back any time in the next five years. Others travel from much further away (London, Fairbanks) to go to this party, which should give you an idea of how important this party is to Dabney alumni.

RGB controlled diffuse illumination lamp :

Suresh successfully modified a modern style diffuse diffuse illumination lamp for controllable RGB color. He even designed and ordered a custom multi-layer board for the thing. I will try to track him down and see if designs and photographs are available anywhere.

CCFL octahedron :

This project was a wire-frame octahedron, approximately two feet on each edge. An octahedron can be viewed as 3 intersecting squares, once for each of the x, y, z, axes. In this design, each axis was assigned a specific color. The octahedron was constructed using two standard cold cathode fluorescent lighting tubes per edge, driven by black-box driving hardware that is powered by 12V DC. 12V is switched to the various edge drivers using darlington arrays controlled by an AtTiny2123(?), with 12V pulled from a modified desktop computer power supply. The skeleton of the octahedron itself was build by cutting wooden dowels to size, drilling a hole through each end, and joining the ends with zip-ties. The lights and driving hardware was also secured to the skeleton via zip ties. A great effect of the hue rotation on tie-dye style patterns is to cause the location of edges to appear to shift as the color changes and alternatively illuminates different parts of the pattern.

Revised goggles :

The goggles you see in these photographs still use the same old LEDs in ping-pong ball design, stripped down and controlled by an AtTiny13a. I would not recommend this design, as technically the chip is unable to source more than 60mA, where the goggles may require up to 120mA. Offhand the AtMega(4,8,16)8 chips are the only ones I can think of that can source sufficient current, and since they can hold more elaborate programs might be a better choice for future designs. Additionally, although the AVR micro-controllers can function at a range of voltages, the nonlinear V-I curve of the LEDs means that attempts to balance the white-point using resistors must be in the context of a well defined voltage ( preferably a constant 20mA current source, but that takes up board space ). Additionally, I was surprised that the internal resistance of coin-cell Cr2023 batteries limits them to approximately 0.3mA continuous draw. Although the much higher mean current draw of ~20mA for the goggles can be supported, this will cause the battery voltage to drop during operation and the LED white-point to drift. Eventually the voltage falls below the operating voltage of the AtTiny. The coin-cells will recover after about ~30 minutes of rebound. We're still seeing some problems with party-durability but hopefully refining the PCB board design and construction can improve on this. Building the goggles is incredibly annoying and I doubt I shall be constructing any more by the old methods for some time. I'm still a bit baffled as to how someone magically managed to repair solder connections and rebuild the connector on one of the goggles in the middle of the party, but ... thats Dabney house for you.

Laser Spirographs and Monolith-Monitor tower with EL wire :

I don't have good documentation on this at the moment, other than this system crashed a lot during the party, but was still super awesome.

Thanks to everyone who made this happen, it was great to see you all again.