How To Spot A Psychopath

Via TechnicBricks, yet again:

This magnificent contraption is not new - the clip's from 2007, and Make noticed it in early 2008. But I think you'll agree that its creator, "superbird28", could do with some more publicity.

If you'd prefer a more compact version:

This reminded me of another Make find, just the other day:

This is a system used in real factories, to reduce the machinery needed to handle different goods, or the same goods at different stages in the manufacturing process. Note that the cylinders and the cubes don't mix.

If you had to name one electrical component that just shouts “mad scientist”, the knife switch would be that component.

(I’m not counting the Jacob’s Ladder as a “component”, here.)

Connecting lightning to your not-yet-animated monster, activating your death ray, powering up the time machine; all jobs for a big old two-blade knife switch.

Knife switches have plenty of actual practical uses in the real world. Even small ones can switch very high current, their position is obvious at a glance, and they can put up with a lot of abuse. They’re obviously not a great choice for high-voltage switching, but they’ll usually actually do that very well too - you just have to stay away from the live bits.

(Knife switches made for really high-voltage operation often have special spring-loaded doodads that stay connected as you raise the knife-bar, then snap up very quickly. Their purpose is to break the contact very rapidly, so you don’t pull an arc between the terminals.)

So naturally I had to get one. And not one of the little plastic science-classroom versions with binding posts or spring terminals; I wanted something beefy, as were and still are used to isolate radio gear from the big lightning-attracting antenna outside. A knife switch also makes a dandy automotive battery isolator, but I didn’t want one of those, either.

After a year or two of e-mails from my saved eBay search, I found just the thing.

This handsome object cost me $AU28.11 delivered, which I thought might have been a bit too much, until it arrived. I now realise I got a bargain. This thing’s way cooler than I expected it to be.

All of the terminals and contacts work OK; a couple of the hefty terminal screws were seized and remain tight after cleaning and oiling, but this is a perfectly functional piece of gear.

The Bakelite-slab base is only about 14 centimetres square (5.5 inches), but the whole assembly weighs about 1.86 kilos (4.1 pounds). And it’s surprisingly complicated.

Your standard two-blade knife switch is simple enough. It’s either a dual-pole, single-throw, or a dual-pole, dual-throw (if you don’t know what this means, check out the Wikipedia article on switches).

This thing, in comparison, is a freakin’ logic puzzle.

It’s got six terminals, and two separately hinged - but electrically connected - blades. The worn (and now lightly polished!) wooden handle is in two parts, too, one for each blade. But the two handle parts form a rebate joint.

This makes it possible to have both blades down, both blades up, or only the left blade up. But, because of the rebate joint, you can’t have the right blade up and not the left.

Let’s number the terminals clockwise from the one at the bottom right of this picture. So the one to its left is terminal 2, terminal 3 is the one on the back connected to the bases of the blades, and so on to number 6, which is partly obscured by the wooden handle in the above picture. Pay attention, there will be a test.

With both blades up, terminals 1, 2 and 6 are connected to nothing, and terminals 3, 4 and 5 are connected to each other.

With the right blade down and the left blade up, terminals 1, 2, 4 and 5 are disconnected, while 3 is connected to 6.

With both blades down, terminals 1, 3 and 6 are connected to each other, and terminals 2 and 4 are connected to each other; only terminal 5 is no longer connected to anything.

(If you can’t quite see how that is the case, note that the middle section of the left blade, the lower one in the above picture, has a copper sleeve around it that’s insulated from the blade itself. When that blade’s down, the sleeve connects terminal 2 to terminal 4, but not to the blade itself.)

Oh, and terminals 1 and 6 are connected to the blade contacts via a couple of bits of might-perhaps-be-fuse-wire-but-probably-isn’t. So you could easily connect either or both of them to some other part of the assembly, if you wanted.

(Does anybody know of a piece of software that’ll take a description like this - “in state A, these parts are connected, in state B, the situation changes to this”, et cetera - and will then draw you a diagram? I started drawing it out by hand in a flowcharting/circuit-diagram program, but then realised I had no idea how to draw these crazy ganged switches.)

The baseplate bears a little oval plaque that says:

(It just occurred to me that the switch could easily have been used for switching railway signals of some sort. The rebated handle interlock could be for something like preventing green lights for both directions on one line.)

I actually will use this switch as a switch, from time to time. But when it’s not in use, I think I’ll hang it on the wall somewhere.

The original poster of the MetaFilter Space Lego article I mentioned in passing in the last post didn’t explicitly mention something, so I suppose I’d better:

Lego are making Space sets again!

More or less.

(I originally started writing this as another comment on the MetaFilter page, but it turned into a whole big thing so I fluffed it up into this blog post. Regular readers may find this a bit repetitive, but there’s got to be something on this blog for people who’ve just stumbled in, looking worried and trying not to make eye contact with the regulars.)

For many years now, Lego have had space… ish sets, like the Life On Mars and Mars Mission series, and the older UFO line.

Now, though, they’ve got a new Space Police line, which is very close to being good old-fashioned Space Lego.

The first Space Police sets came out a year or three into my own Lego “Dark Age” (the period of time between when a person gets too old for Lego, and when the same person gets old enough to start playing with it again). They were clearly Space sets, just with a few new pieces and a different colour scheme.

(Lego’s most offensive striking current colour scheme is on display in the interestingly-Technical-under-the-skin Power Miners line. Lime green and Day-Glo orange, baby!)

Lego entered their own Dark Age shortly after the first Space Police sets. In the 1990s, they spent a lot of time making sets that were difficult to love, because they had lots of special-purpose pieces. They even made “juniorised” sets that were, in essence, Lego for kids that didn’t actually want to play with Lego. Those sets contained many complex single pieces that should have been assembled out of several other pieces - see this post for a particularly egregious example.

They’re much better now, though. Lego still have a few licensed lines that us oldies usually don’t much care for. Personally, I think almost all of their Star Wars sets look awful; I think Star Wars ships just don’t look right in Lego, except in the large scale used in the multi-hundred-dollar flagship sets. And then there are the “Bionicle” action-figures-made-from-Lego that also have little appeal to most adult Lego fans - though the skeletons of Bionicle figures are very Technic-y, with many very useful pieces. Technic itself has changed a lot, though not actually for the worse, if you ask me.

But Lego have also gotten back to their roots, and now make plenty of good old-fashioned sets, large and small, full of general-purpose pieces just like in the old days. (Except the packaging is flimsier, with none of the useful old blow-moulded plastic trays; now it’s just a box full of plastic bags of pieces.)

There are now many fantastic midrange sets with only a barely higher percentage of specialised pieces than there were 25 years ago. And there are also sets that could have been sneaked into the 1982 catalogue without looking out of place. Look at the #6192 Pirate Building Set, for instance. Lego has an actual two-piece shark now, which looks hilarious with some frickin’ lasers on its head but isn’t general-purpose at all. There’s nothing it can possibly be except a shark with a few connecting studs. But the Pirate Building Set’s shark is a cheerful-looking blocky creature made from several separate pieces, in the old style. (See also that set’s catalogue-number-adjacent relatives, the Fire Fighter and Castle Building Sets.)

If that’s the kind of Lego you like - or just the kind you want to buy for your kid - then you can ignore the licensed stuff and just get the new-old-style sets. You don’t even have to buy sets you don’t much want just because they contain pieces you need for the model of your dreams: There’s an auction site just for Lego full of enterprising dealers who part out sets and sell the pieces separately. So you can, for instance, buy a few yards of the new chunky track pieces, and the sprockets to drive them, surprisingly cheaply.

I also harbour a great affection for the current “pocket money” sets, that give you just a minifig and a smattering of accessories. A better way to inexpensively start to tease other grown-ups out of their own Dark Ages has not yet been discovered.

There’s this cop and his dog, this street trader, this brand-new Space Police officer, this garbage man, this builder, this fireman, this street cleaner (with one of those uncommon rubbery brushes), this kayaker, this God-bearded (Shark!) wizard, this knight, this mailbox robot, this troll, and this little spaceship. (Note that the pre-2009 sets are no longer likely to be available at your local department-store-with-a-Lego-section.)

My absolute favourite, though, is the pirate with a fish on a stick, and an extremely minimalist campfire.

The pirate’s opposite number is much better armed, but that brave smile cannot conceal the obvious fact that he’s having a lot less fun.

Hans Andersson is a fellow who made a Lego Rubik’s Cube solver (which, amazingly enough, is only one among many).

He has now gone one better.

Possibly quite a lot more than one better, actually.

Yes, this is a Mindstorms NXT robot that solves sudoku. It’s got pretty good penmanship, too.

Like the Lego 3D scanner, Andersson’s new creation isn’t what you’d call the fastest of robots. But if you’re not in a hurry, I’d say this robot does its job considerably better than the also-amazing Lego movie projector.

(Via, once again, the excellent TechnicBricks.)

A reader pointed out yet another “water powered clock” to me, and asked:

What do you think? Scam, right? To me it sounds like it’s got a battery in it, and water is just a conductor for it. “2 year lifespan” makes me even more certain…

Yes, that’s kind of the deal.

Herein, I shall shamelessly reprint and slightly expand something I previously wrote as a comment on Book Of Joe:

Man, I’m tired of things like this. “Fruit Powered Clock”, “Water Powered Radio”, “Potato Powered Web Server” (that one required rather a lot of potatoes, as I recall). Some of them are complete hoaxes, but the commercial ones all do actually work. Every single one of them is misnamed, though.

In all of these cases, the object or liquid in between the electrodes is not “powering” anything. It is acting as the electrolyte, like the goo inside a flashlight battery or the acid inside your car battery. The actual power comes from an electrochemical reaction between the electrodes. For little gadgets like this one, the electrodes are generally paddles of copper and zinc.

All the electrolyte does is transport ions from one electrode to the other (and collect contamination along the way, which is why you mustn’t eat the orange that’s been “powering” that clock for the last couple of days). The actual power comes from the electrochemical difference between the material from which the electrodes are made. One electrode will be slowly eaten away, and the other will slowly crust up with crud.

To say otherwise - as the packaging for these devices invariably does - is like saying that your television is “powered by wire”.

Science toys are fantastic.

Science toys that’re dumbed down until they’re lying to us are an own goal.

Behold: Jumpei Mitsui’s minifig-scale Yamato (via).

Six years in the making, 6.6 metres long, 150 kilos. (It’s only a “waterline” model, of course; it’d weigh even more if it had the whole keel.)

You know, at this scale - about 1:39.8 - a Star Destroyer (a normal one, not some special-order version) would only be about 40.2 metres long (132 feet).

I’m just sayin’.

A reader writes:

I live in Taiwan, and I just came across a new LED device which seems very cool.

First, here is a link. It’s all in Chinese, unfortunately, and I can’t read it to translate for you, but there are at least some photos to give you an idea.

[Here’s a goofy machine-translation, which gives the thing the name “Aurora”, which sounds good enough to me. The price, 1699 Hong Kong dollars, is as I write this about $US220.]

Basically, this works like a Lite-Brite, but with LEDs. There is a black PCB, entirely pierced through with holes. It has no wires, and there are no visible electronic components except for the DC input at one corner. You can plug in LEDs on either side, front or back, in any pattern you like. It’s powered by either a wall-wart, a small battery pack, or a USB power connector.

A friend of mine here showed it to me tonight, and it was very impressive. Water-resistant, even - he poured a beer all over both sides of one with many lit LEDs, and there was nary a flicker.

Anyway, if you’re interested, I could probably find out more about it.

Doug

I immediately, and completely wrongly, picked the Aurora as a cheaper clone of the Bandai Luminodot (dodgy translation), which was all the rage on the gadget blogs a few months ago. Some hipster has presumably bought himself a Luminodot for $US200 delivered on eBay by now, but I sure ain’t.

Doug was quick to point out, though, that this thing is not a backlit-plastic-pegs device like the Lite-Brite or Luminodot, but a bunch of little powered breadboard-ish holes, into which you can plug as many or as few LEDs of whatever colour you like, and have ‘em all Just Work with no fooling around with supply voltages or current-limiting resistors or fancy driver pucks.

(I think a cheaper version of the Bandai doodad might be makeable with a laptop CCFL backlight panel and little black shutters that open to let light out when you push a peg though them. Or you could do it the Lite-Brite way, and put a new sheet of black paper over the light for the pegs to puncture every time you want to make a new picture.)

Undaunted, I immediately developed total certainty regarding the Aurora’s similarity to another light-array gadget.

That gadget is the open-source “Peggy” invented by Evil Mad Scientist Labs, which is now up to version 2, and available as a kit.

The different Peggy versions are capable of various kinds of animation, and can even be used to display (very low-res) video.

The array Doug saw may, like the Peggy, only actually light one row or column of LEDs at a time, but cycle through them too fast for any flicker to be visible. (It may or may not do the same devious multiplexing as the Peggy, and is almost certainly a lot less “hackable”.)

The Aurora is clearly being promoted as beign useful for commercial signage, as an alternative to the custom-made, ultra-bright LED-array signs that I’ve seen sprouting around the place.

Doug was under the impression that the retail price “for a board about a foot square” was only around $US30, plus another $US10 for the power supply. That’d make it worth buying just for the amusement value, but doesn’t line up with the $HK1699, $US220-ish price on the product page.

Never mind, though; when an odd toy starts being sold on any Web site ending in .tw, its price will probably be in free-fall soon.

Yep, that’s a Lego movie projector all right. The frame-rate’s a bit short of 24fps and the film moves a bit while the light’s on - but c’mon! Lego movie projector!

Via TechnicBricks, again. That post also mentions the first TechVideo from this year…

…a vending machine made by the same guy, Ricardo Oliveira.

This is a contact-type 3D scanner. Philippe “Philo” Hurbain (co-author of “Extreme NXT“, a book about advanced Lego robotics) made it to help him import odd-shaped Lego parts into the LDraw Lego-CAD program.

As you may have noticed, the scanner is itself made out of Lego. I think the only non-Lego parts in it are the actual needle that prods the thing being scanned, and one extra-flexible cable going to a standard NXT light sensor.

All the rest - drive components, sensors, you name it - is 100% Lego. The brain is Mindstorms NXT. Hurbain has made various add-on sensors for Lego robots, but I don’t think he’s used any of them in this.

Apparently, the new linear-actuator parts are accurate enough for this job, when you drive them with one of the NXT motors, which have built-in position encoders.

More info on Philo’s site.

Everybody who found the SX-150 demo from that post to be agonising listening: The first of these videos is safe for you. The second is not.

This track’s held together by the DS-10, of course, which is a proper little music production environment. Both the Stylophone and the SX-150 are sweetened up by a lot of reverb, as well.

But just the same - this is actual music, using the actual particular capabilities of these funny little synths. The SX-150 has My First Analogue Synth tweakability, and the Stylophone lets you do effortless “keyboard” glissandos, including only the “white notes” or - with some more dexterity - the whole chromatic scale.

Play these instruments “dry”, though, and you get something more like this:

Still an actual tune, but not exactly easy listening.