Back, oh, around 1998 maybe, Andy Looney asked me if I could make the flashing chasing-light device that you always see on Federation starships, under the main viewscreen.
(You know what I mean. It goes "ping", very quietly.)
He asked me because he'd just gotten one wall in Wunderland painted with a Lunar landscape. That room was already referred to as "the Bridge", due to overwhelming video technology, and he thought it needed a flashy-light thing. And I'd recently completed and shown off the Cloak of Light, which made me some sort of expert on flashiness technology.
I said I'd think about it.
Then I moved back to Pittsburgh.
Of course it's pretty easy to rig a chasing-light circuit out of LEDs and some Radio Shack parts.
Or I could have bought Christmas lights off the shelf. But this is no fun. I wanted to use electroluminescent technology.
The ribbon I used on the Cloak is expensive (and, since then, out of production) but Indiglo nightlights are cheap. Quick experimentation showed that, while a nightlight is dim green when hooked up to wall current, it shines a bright blue-green when driven by an inverter meant for electroluminescent ribbon or wire.
(You can buy blue-green Indiglo nightlights as well. But these actually use the same lighting element as the green ones -- they just have a blue filter in front!)
The influence of current on color sparked another thought. The inverter pushes out AC at about 1500 Hz, whereas wall current is of course 60 Hz. What if I could build a control circuit that would vary the frequency continuously between these rates? Instead of lights that flashed on and off, I would have lights that started as a dull green, slid up the spectrum to aqua, and then slid back.
This noble cause hovered in my mind for months. But I just didn't (and don't) have the electronics clue to execute it. I think in digital; any circuit more complex than a light bulb makes my head hurt. I looked in circuit sourcebooks, textbooks, and Radio Shack lab notebooks. I asked people on the Net. I tried to extrapolate from similar circuits. I got a lot of head-hurt.
(Reader poll! Reader polls are necessary on Web sites, right? Okay, here's the exact problem I was trying to solve. Read it carefully before you respond. Entries will be posted on this page for enthusiasts to try out.)
In October of 2000, I was looking through the on-line catalog of Coolight, purveyors of EL wire and related gizmos. Among those gizmos, I saw -- chasing-light inverters. Specifically, the LyTec IT-9361 five-way sequencer, and its cousin the three-way IT-9361A.
Now, these gadgets didn't do the clever frequency-sliding that I really wanted. They just switched an AC current between five (or three) output wires. Much less nifty.
On the other hand, they cost $15.50 each. With several patterns programmed in. I bought one, and went hunting for the other parts I needed.
Parts was parts -- I mean, not too difficult. I figured I'd use a rectangle of clear plastic, with Indiglo nightlight elements attached to it. Alligator clips bite the tabs that stick out; wires are soldered to the clips, and run to the sequencer. Or rather, to be more modular, the wires would run to a DB-9 plug -- the familiar trapezoidal plug you see on a PC serial cable. The sequencer wires would run to the matching DB-9 connector. The wires, and the bottom edge of the rectangle, would be covered with a length of clear vinyl hose -- this would cover the electrically-live parts while still looking nifty and tech-functional. And clear. Transparency was a design goal here.
I spent an amusing day running around the Raleigh-Durham-ChapelHill triangle after these items. The plastic sheets came from an office supply store (sign covers). Radio Shack sells clips and DB-9 connectors. But the nightlights? I tried Linen World, Best Buy, Radio Shack, Sears, CompUSA, and WalMart. A total wash. I got one nightlight out of the lot, and that was an oval, not the rectangular ones I was searching for.
(Not that the trip was a total waste. That was October 28th, 2000, and the run satisfied my primal need to make sure that no Playstation-2 unit was available for sale anywhere in the Triangle. I knew it, of course, but I had to check.)
Anyway, straggling home, I stopped at a CVS drugstore. Bingo. Nightlights.
Pause for the familiar ritual of cutting open nightlights. (I had opened twelve of the buggers, a year ago, in a first attempt at making the Icehouse presentation stand. Of course those were the oval kind.) Hint: use a sharp exacto knife; score along the top and sides, repeatedly, not hard, until you can start to pull the front and back apart. You'll have to work harder on the corners. Don't push down too much, or the blade can go deep into the nightlight and damage the element. And cut away from yourself, idiot.
Cutting the appropriate rectangle of plastic from the sign cover was harder. I borrowed a hand jigsaw and went at it.
It was a mess. The plastic burned and melted along the cut. In fact, it fused back together behind the blade. (You can see I tried to remove the narrow strip I'd managed to cut, using a hacksaw. It actually wouldn't fall off -- what looks like a long blackened cut is actually fused together.) Eventually it yanked the blade out of the jigsaw, and I gave up.
Instead, I got a sheet of glass. I already own a glass cutter. Glass cutters are great. You push it along the sheet, leaving a deep straight scratch, and tap the glass -- once -- and tink! You've cut glass. Be careful to sweep up the glass dust that goes everywhere.
The rest was soldering.
DB-9 Connector, Badly Soldered
This was my first attempt. I never actually used it; the other ends of those ten wires aren't connected to either nightlights or sequencer. I did another wire-bundle with four-strand speaker wire, which only required two and a half cables.
Glass, nightlights, alligator clips, and wires.
And when I hooked it up, it worked!
(Here's an animated GIF.)
Well, almost. It turned out the Coolight people sent me an IT-9361A, the three-way, instead of a IT-9361. (I didn't notice because it had five output leads, plus the red-marked ground lead. Hrmph. Two of the outputs turned out to be grounds also.) I re-ordered.
Aside from only flashing three ways, the flashy-light thing worked very nicely. But I didn't like the alligator clips; they seemed too prone to slip, and the vinyl hose didn't cover them very well.
But I already knew I would be making another. One for Wunderland, one for me.
Only a few differences...
Rather than buying yet more nightlights, I used the oval elements from the old Icehouse stand. These are wider, so I got a bigger sheet of glass to cut my rectangle from. A picture frame, in fact -- certainly not the cheapest way to buy glass, but it was easy to find.
I wanted to use copper ribbon, taped flat onto the element contacts, instead of alligator clips. (The U-section edging from the edge of the picture frame would press the tape onto the contacts.) Well, I couldn't find any copper ribbon or tape, but I did find some flat brass clips that would serve. They sort of hooked onto the edging. It's hard to explain... I'll see if I can get a closeup.
Note that this is the back of the flashy thing, and of the oval element. That's why it's black. Fortunately, the gold-colored edging is actually non-conductive plastic.
(Unfortunately, it's not transparent. The goal of transparency is not achieved. Oh well.)
And by this time, the five-way sequencer had arrived. Here's an animated GIF.
I brought the Mark 2 model to Philcon in 2000, for the Pop-Tart Cafe event, and then donated it permanently to Wunderland.
Now my apartment is full of glass scraps, bits of insulation, lengths of wire, and basically it's a mess. Bleah.
Last updated November 22, 2000.
The circuit design problem
I've also used electroluminescent technology in the Icehouse presentation stand and the Cloak of Light
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