Wednesday, February 3, 2010

The Mad Scientists Light Switch

Good evening Mr. and Mrs. America, and all the ships at sea.

While attempting to clear my workbench in preparation to make a somewhat precise high voltage low current measurement, I realized I had more stuff than real estate. My bench was rapidly becoming eleven pounds of shit in a ten pound bag.

One of the projects that's been occupying space either on said workbench, or on the riser shelf above my workbench, or parts of both at the same time, is: "The Mad Scientist's Light Switch". Kindly imagine while re-reading that phrase that it is being shouted through a large public address system with a fair bit of reverb thrown in for good measure.

I thought for sure I'd written a piece in this very journal about it, but a quick review last night turned up nothing but a short reference to it. Perhaps I was thinking of my partial coverage of it over at my Flickr page.

So anyone reading that one little mention here must have thought I'm a bit 'round the bend. They'd not be far wrong of course, but that's entirely beside the point.

In order for me to make room on my bench, I needed to get this damned project -- I shall call it the MSLS for short -- off my bench. As it happens, the MSLS was designed from the start to mount on the wall. Of course, back at the start, it hadn't been quite so complicated. But I'm getting ahead of myself.

For starters, if I could get this thing set up on the wall temporarily, I'd have lots of bench space. So I decided to push on this a while since making a small amount of progress on it would enable any progress on measuring that damned capacitor.

Not that the capacitor has anything to do with any projects whatsoever - for the moment - but it could, and I'll have more idea of how likely that is... AFTER I AM ABLE TO TAKE THIS DAMNED MEASUREMENT.


So anyway, here's what this MSLS thing is, how it all got started, and er, caught a case of Creeping Featuritis.

A really long time ago (decades), an old U.S. Air Force buddy offered to give me a "great big old fashioned knife switch" - hereinafter referred to as the Giant Ass Knife Switch, or GAKS, which he had found somewhere, probably eBay. After hearing his hyperbole about this thing, I eagerly accepted his offer, although he didn't actually have it with him at the time... *cough*

Some time passed and I asked him about it. He thought about it a while, and eventually realized it was buried in a closet which was blocked with quite literally several tons of amateur SETI ground station receiving equipment in three full-height racks... I just sighed and told him to let me know when (if) he ever saw the inside of that closet again.

Several years passed.

We got together for the first time in several years, and I was shocked to hear that he had decided to dump the entire amateur SETI project, had sold all the racks of equipment, and was in the process of cleaning out the previously-blocked closet. He promised to find that switch and get it to me the next time we got together.

Several more years passed.

Did I mention at the outset that this was going to be a long story? No? Well, it is.

To make a painfully long story slightly less painful but not shorter at all, I got my hands on the thing quite a few years ago, found that it was quite as beautiful and impressive and archaic as promised, and it has been languishing around my workshop ever since, looking for a purpose. It's got three poles, a solid slate base about 5/8" thick, lots of copper and brass, nicely constructed.

It could probably handle several hundred amps closed, but there are limits to how much voltage across its contacts (or current through them) that I'd be willing to use with that switch with my bare hands on it. Now with a bit of rope and an arc flash suit, that would be a different experiment story.

ANYWAY, between the moment I first heard the rumor of this GAKS's existence and the moment I got it in my perspiring hands; I had bought a quite nice, but slightly smaller, Big Ass Knife Switch. We'll call it the BAKS for short.

MSLS, GAKS, BAKS. Got all that? Good.

I had the idea that it would make for a great (tho fantastically dangerous) actual light switch for the lights in my workshop. It's not for nothing that Frankenstein is always shown throwing the big switch that powers up the laboratory AFTER he has located the handle with a lantern, torch, or candle. He's also usually wearing thick rubber gloves up to at least his elbows. I used to have a pair of lineman's gloves like those until I outgrew them. They're not for show, and they're very expensive.

You can do things with GAKS that aren't exactly safe to be close to unless you are wearing good protective gear. And don't forget, a lot of the old special effects for those 1950's mad scientists movies were real working, mad science equipment like Tesla coils and huge jacob's ladders built by Ken Strickfaden. His equipment actually WAS dangerous, there wer no optical effects, the camera recorded what was actually happening on the set. At one point, Boris Karloff refused to go onto a set because he thought Strickfaden's equipment was too dangerous.

But I digress. Sorry, favorite topic.

I am actually fairly safety conscious. I've had a few close calls, and I've listened carefully to every one of them. Usually the communication medium has been pain.

So it occurred to me, I could set up the knife switch with six volts across it, hide a short circuit under one side of it so that it shorts the two poles when it is "closed". Then use the six volts to control a relay capable of operating all of the lights that I intend to put into the re-modeled workshop.

Ah, that'll b about four times as much, and more evenly distributed, than it has now. It will be bright. It needs to be. I've learned this lesson over and over again. I have a twin 40 watt fluorescent fixture under the riser shelf of my workbench. It's priceless.

So anyway, anywhere from 5 to 10 amps of modern, T5-HE daylight and warm mixed lamps with high frequency electronic ballasts (no visible flicker, probably consumer about as much energy as my old starter type fixtures do now). I'll need a good sized relay, but I probably have one lying around, no problem.

Well okay, I gotta come up with a 6 volt power supply. Needs to be well-isolated from the power line - so add an isolation transformer...

Gee, it sure would be cool if that big impressive knife switch could actually DO something, or pretend to, when you threw it.

An old friend from fandom once described to me a device which made some impressive noises when activated, and I think it was related to a light switch. I thought about this for a while.

It occurred to me that a small Jacob's ladder would be a cool addition. But you know, Jacob's ladders are cool and all, but it would get seriously annoying once you were done admiring it. I'd better add a timer relay to turn it off after five seconds or so. Amusing when you turn on the lights, and then you can forget about it.

You can see where this is going.

The design got complicated. From the very beginning, the aesthetic I had in mind was half steam-punk and half atomic era science fiction. Big ribbed insulator bushings! Round dials mounted with brass screws! Baked-on crinkled-enamel cabinetry! Heat sinks! Fins! Cooling louvers! High voltage anti-corona spheres! A hand-crafted jacob's ladder with custom fittings to allow mounting in a big copper pipe elbow, with turned brass electrode holders, brass electrodes, and art deco finned finger guards to keep curious fingers from offing their owners! Uh, an extra neon sign transformer because a single piddling little 5mA NST couldn't generate enough heat in the arc to create the hot air that causes the arc to rise.

And so on and so forth. Plus, the wires all still need to be connected to interesting looking things, so that they appear to actually do something, preferably something arcane and vaguely dangerous looking. I want a physicist specializing in high power electronics to look at this thing and say, "okay, I can see it is beautifully constructed, and probably quite dangerous... but what in the hell does it DO??"

You have the general idea. If you've had the patience to read down this far, you deserve a small reward:

MSLS The Device progress.jpg

This is the main control box, hereinafter known as The Device. It will contain the neon sign transformers, 6VDC supply, isolation transformer, timing relay, and some associated gewgaws. Eventually, it will also contain a solid state sound record/playback chip, a small Class B amplifier, and a small speaker, so it can make interesting sounds (think Krell Mind Amplifier turning on, or turbines spooling up).

The upper left and upper right quadrants above the meter will contain a pilot lamp and an override switch respectively, in case something goes wonky with the power supply or 6V wiring, I can still turn on the lights in the shop. The finned bits on top will be extended upward a little with some contrasting tubing (they are actually power resistors).

The mini-Jacob's ladder looks like this, so far:
horn gap partial assembly

It includes customized copper piping and the obvious elbow. Not yet installed is a finned art deco vent at the top that will allow warm air to escape and keep all but small conductors (held by very stupid people deserving of electrocution) away from the 3,750 VAC (to ground) inside. I've cut the parts, but still have some very careful drilling and gluing to complete that bit.

The Jacob's ladder will mount through a custom brass flange (which I am working on now) to the side of The Device.

Please note the custom fabricated shelf brackets with pulp science fiction inspired "lightening" holes. The wooden shelf itself is not yet complete - it will get some kind of edge treatment - routing at minimum, possibly a metal rail of some sort.

The conical insulators on the front panel will carry a whole 6 volts through some big impressive coiled wires to the BAKS. (The GAKS was too big to fit where I wanted to mount a light switch.) Something like this:

[mp] Mad Scientist's Light Switch Project mockup (cc).jpg

Note that you're looking up from roughly my 5'10" nose -- the top of my workbench and drill press pulley housing are visible at lower right and at the extreme left edge of the image is a pass-through about 7 feet in height.

The lower connections of the BAKS will be wired to yet more impressive but ultimately non-functional greebly bits.

And that's the way it is.


TravisD said...

Instead of a quiet little relay, you really need a big-honkin Contactor that will close and with a very satisfying KA-CHUNK when (de)energized.

Bill Lemieux said...

Oh fear not, I never said the quiet little relay would only be accompanied by the Jacob's Ladder. I have several other effects I plan to add to it, but for now, I need to get it operational and off my bench.

Gordon said...

I knew Ken Strickfaden when I lived in LA in the mid eighties. He was a great guy, still a lot of fun as he'd gotten old.