Hacks

A Bingo Shooting Device going off

A lot of the traps my friend Jay and I design use little mousetrap-like devices that go bang when opened, usually sold under names like “exploding toilet seats,” or as the main mechanism in exploding pens. It consists of a hinge that is closed over a spring-loaded hammer. When the hinge is allowed to open, the hammer is released and strikes a percussion cap, causing a loud bang. Not too long ago I discovered the history of this wonderful invention, which was originally called the Bingo Shooting Device and was invented exactly 100 years ago this year.

The inventor of the device was one Sam S. Adams, who in 1907 was trying to follow up on his previous year’s successful invention of sneezing powder (a coal-tar product sold under the name “Cachoo”). Copy-cats were underselling his sneezing powder, and so he moved on with the Bingo Shooting Device, and installed the device in decks of cards, cigar boxes and “books with saucy titles” (to quote a 1941 article about Adams’ success).

Adams went on to invent some of the best-known gags of the last century, including the Snake Jam Jar (a jam-jar in which a spring-loaded snake jumps out), Racket Wireless Message (an envelope that rattles when opened, now sold as “Rattlesnake Eggs”), the Dribble Glass, a telescope that gives the user a black eye, soap that stains your hands, and of course the world-famous Joy Buzzer — basically every well-known joke but the Whoopie Cushion. His company, now called S.S. Adams Company, still exists and sells novelty items to this day.

One of the big demos at last weekend’s Maker Faire was a life-sized version of the 1963 board game Mouse Trap, with bowling balls instead of marbles and a two-ton safe dropped from a crane instead of a cup dropped on a plastic mouse. They tried running it six times over the weekend, before finally succeeding on their seventh and last attempt:

Instructables.com (a Squid-labs startup founded by friends of mine from MIT) has three contests going for the best handmade item plus accompanying instructions on how to make it, something like $15,000 in prize money (not to mention bragging rights):

• Win a BrightStar Laser Cutter Contest: Publish an Instructable on any subject before June 17th. Grand prize is a BrightStar LG3040 laser cutter worth over $6000.

• Sew Useful Contest: Three categories: most useful thing that helps others in need, the best combination of sewing and technology and best Instructable tutorial. Winners in each category get a Singer QUANTUM® 9940 computerized sewing machine.

• iRobot Create Challenge: Build a robot to do something interesting / useful using the iRobot Create Programmable Robot platform (based on the Roomba vacuuming robot). Don’t have an iRobot Create kit already? iRobot Corp. is donating 15 Scholarship Robot packages to those with the most interesting proposals. If you build the robot and enter the contest with it you get to keep the robot, even if you don’t win. First place in this contest is $5000, second place gets a set of iRobot home robots worth just under $1000.

I’ve finally posted a write-up on Jay’s Laser Trap from this Christmas over in my traps gallery:

This is a strikingly beautiful trap. When placed in a darkened room, you can see a faint and ominous glow coming from the chest even before testing the latch. Opening the chest reveals faint laser lines criss-crossing back and forth across the mouth of the chest, lines that might be missed completely in a well-lit room but become bright if you blow smoke or mist into the box. Breaking a beam with your hand, or bump one of the carefully-positioned mirrors that bounces it from source to receiver and you trigger an alarm.

Check out the traps gallery for the full description.

I just posted a few different methods for disarming the Under Glass trap over in my traps gallery:

There are several potential methods to disarm this kind of trap, though depending on the particular trap implementation some of them may be more or less effective. I’ve only actually used the first two methods, the others are suggestions I’ve heard that sound plausible but haven’t been field-tested. Note that there are various destructive methods you could use to open this trap without setting it off, such as drilling a hole from the underside, but that’s considered cheating: the idea is to get the “treasure” out of the box without setting off the trap and without damaging either the box or trap itself.

• Strong Magnet: Depending on the strength and position of the popper, placing a strong magnet against the glass (or box bottom) can keep it in closed position while you remove the dome. My earlier prototype with the popper stuck to the glass could be disarmed by simply placing a very strong rare earth magnet against the glass, and then whacking the box, dome and magnet down on the arm of the couch so that the popper would snap shut from the inertia. Once the popper was closed, the magnet was strong enough to keep it closed such that the dome, magnet and popper could all be removed without setting off the cap. (Unfortunately for Jay, the version I gave him was simply too powerful even for the four large rare earth magnets I had brought with me.)

• Rice: The second option is to fill the dome with a substance that can fit through the small crack between the box and glass but still interfere with the firing mechanism. I used grains of rice, which could be forced under the dome using a thin piece of spring steel. After I had a decent amount of rice inside the dome itself I was able to lift it out of the box without firing the cap. The hammer sprung down, but wound up with a single grain of rice between it and the unfired cap. Water would also probably work, though it might damage the box or contents. Note that evacuating the dome of oxygen (for example by using a wine preserver gas) does not seem to work — I’m guessing the caps provide their own oxygen source.

• Wax / glue: We haven’t tried this, but it might be possible to carefully maneuver some sticky wax or glue through the crack in the side such that it holds the playing card to the underside of the glass dome, thus pulling the card up with the dome when it’s removed from the box.

• Flexible shim: We haven’t tried this yet either, but there exist metal shims that are extremely flexible, and such a shim might be able to actually bend through a crack between the glass and box side and get inside enough to block a popper from firing. This was essentially Jay’s strategy using pipe cleaners, but they weren’t quite flexible enough, and one of the poppers got free and went off.

Remember back to your misspent youth (or recent adulthood) spent playing Dungeons and Dragons, and how your adventuring party sweated as your thief tried desperately to disarm all the traps before opening a treasure chest? It’s in that spirit that my friend Jay and I have exchanged trapped presents every Christmas for the past sixteen or so years.

When people ask me how to disarm a trap I’m giving Jay I’ll often joke that “I just design them, disarming them is his problem,” but I actually like to know that I can get through it before I hand it off to Jay. This year’s trap almost had me stumped, and I spent almost as long figuring out how to disarm my trap as I did designing it. The trap is even more maddening because there’s nothing hidden about it — after you open the box you can plainly see all the trap mechanisms through a glass dome, just as plainly as you can see it’ll be almost impossible to get any tools at them without setting it off.

I’ve just added a write up and video of the design, called Under Glass, to my traps gallery, and I’ll be adding a write-up on Jay’s trap (which was quite cool this year) in the coming week or so.

This illusion is great — he’s using an after-image to make a black-and-white photo look like it’s in color. (via Mind Hacks.)

Update 6/12/06: He’s now posted a tutorial on how to make these illusions yourself.

The mad scientists at EepyBird.com have a fabulous live video of their Mint-powered Bellagio Fountains. (By way of Aileen.)

My latest project: attach laser pointers to my dumbek drum so I get a mini-lightshow shinging on the drum head every beat. Total cost (with the exception of the dumbek) was about $5.

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