[MakeShift was a column and competition, by MacGyver creator Lee Zlotoff, that ran in Make: magazine for its first five years. This challenge appeared in Make: Volume 16, 2009. Read past installments of MakeShift here.]

The Scenario

You’ve worked late into the night at your computer engineering job in the high-rise headquarters of an international bank, and you’re finally heading to your car with your briefcase in your building’s subterranean parking garage. Your car is the only one left on this dimly lit level, parked along a cement wall right near the elevator. But, as you pull out your keys and are about to hit the unlock button, you hear a loud beeping behind you.

Startled, you turn to see an object against the wall just a few feet away with a pulsing red light on it — and in the poor light, you can immediately make out an illuminated timer which is now ticking away the seconds from a 3-minute window!

There is a jumble of multicolored wires, and an array of three motion detectors set to cover a 180º field off the wall, all of which are wired into a small black box sitting on a large brick-shaped object that’s slightly smaller than a shoe box. Also, atop the brick and on its ends, you see three horizontal glass tubes that appear to contain mercury with wires at both ends, as well as a metallic-looking cylinder with several long wires jammed into the side of the brick-like mass. There’s little doubt in your mind now that this is a bomb! — and your arrival here must’ve set off the timer.

The Challenge

Though you know how mercury switches work, you’re uncertain of the purpose of the motion detectors, or of the black box. Could it contain a hidden transponder? If you try to move out of range or call for help with your cellphone, might your attempt to flee or use the phone set off the device? Hell, even pushing the unlock button on your key ring could send the wrong kind of signal, right? But panic is not an option, as it seems you have less than three minutes to decide your best course of action. What are you going to do?!

What You Have

Your briefcase and pockets contain what a computer engineer might normally have, within reason — if that includes a Swiss Army knife or Leatherman tool, so be it. Beyond that, your brain is the best tool you’ve got. So, think fast, and … good luck!

Analysis and Commentary

Clearly a challenge like this has the inevitable effect of dividing all you makers into two groups: those who know something about bombs, and those who don’t. Still, we thought it would be interesting to see how novices and experts alike might approach this situation, in the hopes we might stimulate some creative thinking and maybe all learn a little something.

And, as always, the entries we got were as fascinating as they were technical and original. (One entrant went into Batman mode — complete with dialogue. And another was so taken by the drama of the situation they wrote a brief short story as their entry. Can the graphic novel be far behind?!)

Granted, finding oneself confronted by an explosive device is a pretty remote possibility. Then again, given the uncertainty and volatility of the world these days, it’s hard to argue one shouldn’t be prepared for almost anything — which is why we thought the challenge was worth a shot.

So, given the situation as described, what should you do? Many of you seemed to think the simplest response was to forget your briefcase and your car and just run like hell. A perfectly understandable response, but even if it didn’t trip the motion detectors to set off the bomb, it’s not exactly what we were looking for.

Then, of course, there were those who figured whipping out your phone and dialing 911 was the best course. Putting aside for the moment the fact that we take pains to prevent that option in virtually every MakeShift Challenge, it still wasn’t necessarily the best course of action. First, you’re in a subterranean garage where cell reception is dicey if available at all. Then, as many of you pointed out, attempting to make a call might trigger something in the bomb to make it go off — which is why at least a few of you suggested pulling the battery from the phone so it couldn’t send any signals. (Good thinking!) Add to that the timer counting down from 3 minutes and (assuming you got through on your cell) even a super rapid response would most likely arrive too late. So, while an understandable choice, we didn’t really think the cellphone provided much of a solution until you’d found a way to neutralize the device and get out of the garage.

Okay, so you’ve decided to face the situation head on … now what? Several thought the best approach, or first step at least, was to distract or fool the motion detectors; maybe by swinging your briefcase from a ceiling pipe, or using a cup of hot coffee to produce a distracting heat signature, or (at least one case) to approach the sensors from above by climbing along the pipe depicted overhead, since the beams from most motion detectors are aimed down and not up. Cool and impressive thinking, for sure. After all, whenever you’re dealing with a bomb it’s a crapshoot. Even when you know what you’re doing it can go very badly very quickly. Which is why we tried to make this a relatively straightforward and simple device, like by making those mercury switches apparent.

Many of you came up with a host of intriguing ideas to tackle those, from disconnecting them to shorting them out, to even trying to freeze them. Now, it’s true that in the real world of bomb disposal, liquid nitrogen is sometimes used to cryogenically freeze a device to render it essentially harmless until it can be either dismantled or detonated in a safe place. And it’s true that mercury solidifies at about -39°C (-38°F), which would disable a liquid mercury switch or electrical contact trigger system. But we don’t recall suggesting you had any liquid nitrogen handy. And, to our thinking, messing around with mercury-based contact switches on bombs is in general not a great idea unless you are a really skilled professional, which was also not provided in the scenario. Not to mention that time was a very limiting factor here, and to successfully disconnect or destroy all three mercury switches in less than three minutes, we thought, was something of a long shot.

That’s why, as a bunch of you concluded, the simplest approach to disarming the bomb was the best way. Almost every big explosion is triggered by a smaller one, i.e., the blasting cap/detonator. With precious little time, we thought the most direct approach here was to slowly and carefully withdraw the blasting cap/detonator from the explosive brick (one entrant cleverly unraveled his sock, using the resulting string to do this from a distance).

Once the detonator is removed from the bulk of the explosive, the briefcase and its contents can be used as a shield to further separate the detonator from the brick, simply by placing it inside the briefcase and closing the lid. No doubt it will trash your briefcase, but if it prevents the larger device from going off, a relatively small price to pay. After which you can hightail it outside to contact the authorities, and if you’re dressed for your 15 minutes of fame, alert the media.

While we forced ourselves to narrow down the entries to a few winners (who suggested we not ask how they knew so much about bombs) we must admit that, as remote as this scenario was, it produced some of the most creative and interesting ideas we’ve seen in quite a while. Congrats to all! And now you’ve got us really stoked to see what you come up with on the next one.


The winners of the MakeShift Volume 16 Challenge are:

MakeShift Master — Most Plausible: Dave
MakeShift Master — Most Creative: Jeffrey Swan
MakeShift Master — Honorable Mention: Don Nelson