MacGyver Science: Thief + Painting + Auction + Viro-486 + Justice
Season 5 Episode 2.
Picking a Lock with a Swiss Army Knife
OK, I just want to be clear. The concept of picking a lock isn’t that difficult. You need two things — something to torque the lock and then something to push the pins up. MacGyver uses his knife to apply torque and the toothpick to push up the pins.
Mercury Switch Bomb (fake)
It’s not a Mac-hack, it’s the thief. She puts a package in MacGyver’s hand and says that it’s a mercury switch bomb. If you move it, it blows up. It wasn’t. Here is how a mercury switch works and a similar switch you can make without mercury.
Lasers and Electric Wires
Let’s start with lasers. The idea of a laser trip wire is the same as that sensor for your garage door. It emits an infrared beam from one side of the door to the other. If something breaks the beam, the door won’t shut (to prevent stuff from getting smashed). The only difference with a laser trip wire is that it uses a laser instead of an infrared light.
Oh, but how do you see lasers? You can’t see a light beam from the side unless it scatters off something. If there is dust or water vapor in the air, the laser beam will reflect off these particles and into your eye so you can see it. But really, that has nothing to with MacGyver’s hack.
Since Desi can’t “feel” the “laser” (they are just strings anyway), Mac decides to fix that. He adds electric wire to each of the “laser” strings and connects them to a power supply.
So, where could you get a high voltage power supply? What about the ballast from a fluorescent light? You would need about 2,000–3,000 volts to get a good shock so this would mean you would need multiple ballasts in series to get your output voltage.
Also, the “pain” level of a shock not only depends on the voltage but also the frequency (for AC voltages). This is a great video.
Now, here’s the other important part. You need TWO wires to get shocked. If you just touch one wire, you won’t get shocked. Now, it’s possible that the “second wire” could be the ground, but you would need electrically conducting shoes and a conducting floor. The other option is to have the two wires together (but not touching) on the same laser wire. This is the way I would do it.
Eavesdropping with a Laser
How do you listen in to people on the other side of a glass window? You can use light. This is real. The basic idea is that when people talk, the sound waves will oscillate the glass window — even just a little bit. So, you can take a light (a laser probably works the best) and reflect it off the glass. When the glass moves, it will change the reflection of the light with the same frequency as the sound. Now you just need a small solar panel or a photodiode to convert that light into an electrical signal that you could hear with earphones.
Here is a great demo that you can try yourself. You just need a small solar panel and an amplified speaker. It’s super simple.
But wait! I have another example. If you want to try something more difficult, here is the same idea with sound transmitted over a laser beam.
OK, one more version. In this case I actually shoot my own voice across the room.
For this example, MacGyver uses a flashlight aimed through binoculars to replace a laser. That should work. Here is my sketch of this setup.
Hiding a Painting with a Mirror.
This is your classic magic trick using smoke and mirrors (or just a mirror). The idea is to make it look like a painting is missing when it’s really still there. In this case, they add a thin sheet of reflective Mylar in front of the painting. This reflects light from a nearby wall so that it looks like there is just a wall there. Here is a sketch.
Of course in this case, the camera is off to the side — but you need to have the reflected light from a wall that is the same as the wall behind the painting.
For this to work, the camera would really have to be in a fixed location — but it was.