MacGyver Season 2 Episode 12 Science Notes: Jack + Mac

Before I get to this science for this episode (there’s some great MacGyver hacks here), let me say something else about the show. The storyline for this episode was great. It had a nice plot, and I really enjoyed the MacGyver and Jack flashbacks. Now for some science.

Photophone

The best Mac-hacks are real. This is real—very real. It is indeed true that this was an early idea for a phone. Here’s how it works.

  • You need a directed light. One way to do this is to get a mirror that reflects sunlight. A parabolic mirror works a little better, but still the mirror is a great idea.
  • Use your voice to shake this mirror. This changes the intensity of the reflected light to match the wave pattern of your voice.
  • Use some type of electrical photo device (solar panel, photo diode, photo resistor) to modulate an electric current to this same sound pattern from the light. Send this to a speaker.
  • That’s it.

For MacGyver’s build, he uses a microphone and connects it to a porch light. The idea is that the microphone will modulate the brightness of the bulb. For this to work, I think it has to be an LED bulb. An incandescent won’t work (I don’t think) since the hot bulb filament won’t change brightness quickly enough for sound frequencies.

There is also the problem of AC vs. DC. If MacGyver connects to the AC power line going to the bulb, this might not work. But still—it’s very plausible.

On the other end of the photophone, Riley uses a police car light as her transmitter. Again, if this is LED it should work (plus the car runs on DC, not AC). Finally, the only problem is aiming. In practice, you need your detector to pick up the changing brightness from that one light. Of course it’s daytime, so there are many “lights” outside. Putting a lens on the detector to aim it would help a bunch.

OK, now you want to build one of these yourself. You should. It’s actually not too terribly difficult. Let’s start with the simplest part—the receiver. The easiest way to get this to work is to connect a small solar panel to an amplified speaker.

Oh, do you know where I got that solar panel? Yes, it was from a garden light. You put these small lights outside and the solar panel charges a battery during the day and the light comes on at night. They were old and the battery was bad, so I took it apart.

Now for the transmitting side of the photophone. I tried to do this with a laser instead of a light (so that I could aim it). It mostly worked, but it’s a bit more tricky.

This is something I need to rebuild at some point in the future. Make it better. But still, this should be in my list of Top 10 MacGyver Hacks. I need to make that list.

Gum Wrapper and Battery to Start a Fire

Ok, actually this was to melt a wire. MacGyver takes a foil gum wrapper and connects it to two ends of a battery. The idea is that the foil will make a short circuit.

But there are two questions:

  • Is a gum wrapper an electrical conductor? I don’t think they are actually made from aluminum foil—but I suspect that many of these do in fact conduct.
  • Would it get hot? Even with a small battery, yes I think it would.

DIY Non-Contact Voltage Probe

MacGyver needs to find wires behind the wall. He puts together this awesome looking probe (or as Jack calls it—a doohicky)

Actually, this prop is great. Here’s why.

  • It looks cool and it’s clearly a combination of multiple items.
  • It’s not specific—it doesn’t show exactly what MacGyver uses. This is good because that way it could still be plausible.
  • Finally, it’s based on something real.

But how does it work? There are multiple ways to detect voltages without touching—I think the most common method measures a super tiny voltage that is created by nearby electric fields. The NCVP is essentially part of a capacitor. When in the presence of an electric field, there is a voltage across the capacitor and you detect this voltage. I need to build one of these—for fun. I’ve seen a very basic version somewhere.

Kitchen Chemistry to Detect Explosives

How do you detect explosives? MacGyver is correct that most explosives are based on nitrogen. If you measure the nitrogen, you can get an estimate of the type of explosive.

There are many things in the kitchen that can be used to detect chemicals. Here is one that you can do at home—it’s a chemical-based pH detector (to determine if something is acidic). The color of this cabbage juice will change color depending on the pH level of the material.

Here’s how to make it.

Laser-Based Wire Cutter

Here’s the problem. There are two bombs that need to be disarmed at the exact same time.

The idea is to use a laser that turns on two identical cutters at the same time. The first thing to use is a beam splitter. This takes a laser beam and breaks into two beams. I guess that’s fairly obvious from the name. Here is a video showing how that works.

For the cutter part, it uses a photocell as the “switch” to turn it on. Here is a rough diagram I created for this hack.

In the end, these two motors might not cut at the exact same speed. But it’s still a fairly fun MacGyver moment.

MacGyver Season 2 Episode 11 Science Notes: Bullet + Pen

MacGyvered Record Player

You only get a quick glimpse of this record player—and I’m not sure it’s the same as this super basic one. But you can build a record player with some pencils and a cup and a pin. Really, this is a fun one. If you have an old record laying around, you should try it. Here is a video.

I want to add something about records. Have you ever wondered why most songs on the radio are around 3 minutes long? The answer has to do with the record single. Here is my longer explanation. But more fun—here is a plot of the average song length as a function of year (the plotly version).

Check it out. So you can see that before the 80s, songs where around 3 minutes or less. After that, the song length got longer. What changed? The compact disc—that’s what. With the CD, there was a new way to share high quality songs with radio stations. This meant that you could easily make a longer song. The end.

Plastic lock pick

If you have a door like this, it’s not secure. MacGyver takes a piece of plastic and slides it between the door and the frame. The plastic pushes the door latch back. Boom. Door opened. Silly door.

Even if it’s easy to do, it’s still illegal to go past locked doors that you don’t own. Don’t do it.

Sodium Hydroxide Doesn’t Grow on Trees

That’s a funny line—because sodium hydroxide is a chemical in tree stump removers. Get it? OK, you aren’t going to find this stuff laying around with other ingredients like nail polisher remover and cold medicine. But you might find all of these things in a meth lab. Don’t do drugs kids.

Could you use this to make a bomb? Sure.

Exploding Dart

Classic MacGyver. He takes a pen and a bullet. With this, he mounts the primer and the gun powered to mount on the front of the pen. Add some paper fins and you have yourself an exploding dart.

Technically this would work—however, there would be a good chance it wouldn’t explode unless you hit it just right.

DIY Vacuum Cleaner Fix

It’s not like the vacuum just stopped working one day. I knew it was on the way out. You could hear it—that slight grinding sound. It wasn’t right. My guess is the bearing in the motor.

Well, one day it finally did stop working. That means vacuuming the rugs with a shop vac (btw—love my shop vac). Oh, the vacuum that broke was a Shark Rotator NV341. Clearly not a top of the line machine, but I found it did the job it needed to do. It had been running well for quite some time (my guess is 5 years). Also, it probably failed because some people (not saying which people) didn’t clean the bin out and clean out the filters. That’s just a guess.

OK, I really didn’t want to buy a new vacuum cleaner for 300 bucks or more—and there is no way I would plop down a ton of money for something like a Dyson. People say they are awesome, but I just don’t see how it would be worth the money. But that leaves me with really just one option—fix it.

The nice thing about fixing something broken is that you can’t make it any worse. It’s already broken. So, the first step is to start taking it apart. Surprisingly, it was fairly easy to get to the motor. Everything else seemed to work fine. I started to take apart the motor, but that was a dead end. But it was clear—the bearing (or something) would prevent it from rotating every so often. It was dead.

Next step—google. Can I find a replacement motor? There were some Shark motors on Amazon, but they didn’t match my model number. I found some on Ebay that were cheaper but again they didn’t match. The ebay motor was cheap enough, I decided to give that a chance. Maybe it would work.

It didn’t work. The new motor was bigger. There’s no way it would fit into my model. But after looking at the two motors (the original and the new one), I decided to give ebay another shot. I wanted a smaller motor. It seems that there are two kinds of Shark vacuums. There are full size models and then the “stick” style. It looks like the Shark Rotator uses the small stick-style motor.

Oh wait! I have another Shark vacuum—the stick kind. The only thing that doesn’t work about it was the rotating brushes for cleaning carpets. But the main motor works. What if I take that motor out of the stick and put it in the Rotator? Surely Shark doesn’t make THAT many different motors.

Damn. That stick vacuum was quite tough to take apart. But I did it.

Here is a look at the three motors (from left to right: the shark stick, the broken Rotator, and the oversized motor).

The stick motor was in some type of plastic shell, I had to get it out of there to use it in the Rotator. Oh, the stick motor was a little too small—but I added that large rubber gasket from the broken motor and it seemed to work.

After putting it back together, the vacuum actually works. WINNING.

But that’s how it goes with fixing stuff. Sometimes you win, but sometimes you fail. Winning is way more fun than failing.

MacGyver Season 3 Episode 19 Science Notes: Friends + Enemies + Border

Crane and winch

The problem with a sinkhole is that the sides of the hole are unstable. You can’t just climb up the side or lower a rope down the side. This would just cause further collapse.

The answer is to get a crane. Something that sticks out over the edge of the hole, but doesn’t interact with the hole. Really, this is mostly just a nice build—but there is one physics thing to discuss.

You can’t just get a pole and stick it out from the truck and expect that pole to lift any weight of significance. It will bend or break. You need some type of structure to allow the crane to exert a torque on the end.

Here are two ways you could do that. First, you could make a type of truss. It might look something like this:

The triangle structure in the truss makes the whole thing rigid. Also, it allows multiple forces on the support end. There needs to be a force that will exert a torque to counteract the torque from the load.

The second method is to use a cable. I’m sure there is a technical term for this, but I’m just going to call it a cable. It would look like this.

I just realized that there was a mistake on the forces for the truss diagram. But you still get the idea.

Bonus, here is my initial diagram for this situation.

What about the tire and rope thing? Yes, this should work. MacGyver takes the rope and wraps it around the tire. This means that the truck’s engine can be the power to lift the humans out of the hole.

DIY Furnace

MacGyver needs to fashion a vascular clamp from some normal clamps. To do this, he builds a mini furnace. This is real. Actually, I built one of these with my daughter so that we could melt aluminum. Here is the video we started with. Note: this is awesome, but also dangerous.

This actually works. There is something amazing about melting metal with charcoal. We started off with a charcoal furnace and an old vacuum cleaner to blow in air. It works, but it goes through a bunch of charcoal really quickly. So, we switched to a propane version—this is much easier.

Bonus—here is my furnace diagram for the show.

Flash Bang

I don’t want to write about the flash bangs—but I should say there is a legitimate basis for this. I just don’t want to tell you.

MacGyver Season 1 Episode 18 Science Notes: Flashlight

Hold on. There’s a metric butt ton of science in this episode. It’s going to be great.

Turning bullet

SPOILER ALERT. This episode has a bullet that can turn. It’s sort of the key plot element in this episode. These dudes are trying to steal the technology for these “smart bullets”. These bullets are essentially tiny guided missiles with fins so that they can turn in flight.

I’ll just leave this Wikipedia link on smart bullets and then move on (it’s not really a MacGyver hack anyway).

The physics of birthdays

Again, not a hack—but MacGyver thinks birthdays are dumb. Well, not dumb but arbitrary. I think he is right. In fact, I use the following phrase on people’s birthday’s:

Happy Solar Orbit Day.

Yes, that is the day the person completes another orbit around the Sun. I like thinking of it that way.

Fixing a generator inverter

There are lots of different types of generators. Most of them involve a gasoline engine that turns stuff. Some times this turning stuff involves a magnet to make an electric current. But what happens when the magnet get’s messed up? Yes, you have to fix it.

A permanent magnet is a ferromagnetic object (like iron) in which all the magnetic domains are aligned. If the domains are not aligned then it would just act like a dumb piece of metal. You can get the domains align by applying a strong magnetic field.

This is exactly what MacGyver does to the generator. He uses a defibrillator to generate the current and forms a loop of wire to create the strong external magnetic field. Seems like it could work.

DIY sand blaster

How do you get people out of a collapsed building? What if you could just cut through the wall? Yes, that’s the MacGyver plan.

In this case, he uses high pressure water mixed with sand—a type of sand blaster. If you have water at a high enough pressure, it can pretty much cut through anything. Of course MacGyver’s water by itself isn’t fast enough. That’s where the sand comes in. When the sand hits the concrete, the abrasive interaction is enough to eat away at the concrete.

Oh, this would take quite a while to work.

Seeing through walls with radar

Yes, this is a real thing. NASA made this device. Here is a description. Basically, this thing sends out microwaves and detects the reflected microwaves. But the magic is that it only looks for variations in reflections caused by small oscillations—these oscillations are from a human heart.

For MacGyver’s version, he starts with a radar gun (from a police car). These don’t use the same frequency as the microwave detector, but he can make a modification. With some software from Riley, that’s pretty much what he needs to get started. It’s at least plausible.

Screw jack

How do you lift super heavy stuff? You need a simple machine. All of the simple machines deal with force and distance. If you can increase the distance over which you apply a force, you can get a greater output force over a shorter distance.

In this case, MacGyver makes a screw jack. You can lift a large mass by turning the screw to get it to extend. In fact, you could do something like this yourself. Here’s how.

Ascender rig

The goal of an ascender rig is to allow some device to move UP a rope, but not down. This means you can climb up a rope one little bit at a time. Here is an example.

Oh, MacGyver made an ascender rig to climb an elevator cable and escape a collapsed building.

Modify laser

The smart bullet is aimed using a laser. Of course the bullet is only a little bit smart. It only aims towards the brightest laser. If you could make another laser that gets the attention of the bullet, you can get the bullet off course.

MacGyver takes the laser sight off a pistol. In order to increase the power output, he burns off a potentiometer. This could work on some lasers—like this.

Oh, DON’T DO THIS. You don’t want a powerful laser without knowing what it can do. These lasers can seriously damage your eyes in ways you wouldn’t be able to predict. Remember, you only have two eyes. Don’t mess them up.

So, they use this powerful laser to redirect a smart bullet. That part is plausible. It’s unlikely they could get a bullet to turn all the way around. They wouldn’t have time to move the laser dot and the bullet fins couldn’t make it turn that much.

Who cares. It was still a great episode.

MacGyver Season 3 Episode 16 Science Notes: LIDAR + Rouges + Duty

What is LIDAR?

Again, this is not a MacGyver-hack. Well, I guess it sort of is a Mac-hack since he designed the LIDAR. So, what is LIDAR? At the most basic level, LIDAR uses a laser to determine the distance to an object. By scanning this laser over some area, you can get a very detailed distance map. If you know the location of the LIDAR (in the aircraft), you get a very nice map of the terrain below.

But how do you get distance with a laser? The laser produces a beam of light (that’s what the “L” stands for in “laser”) and this light travels at a speed of about 3 \times 10^8\text{ m/s}. Yes, that is super fast. However, it’s not infinitely fast. So when this laser light travels and reflects off of something, it takes time to get back to the LIDAR. The longer it takes to return, the greater the distance. That’s the basic idea of LIDAR.

How do you start a jet engine?

I’m not an aeronautical engineer (in case you didn’t already figure that out). So here is my very simple explanation of a jet engine. The key to getting thrust is the same as a propeller driven aircraft: make the air coming in go faster as it leaves. This increase of air speed (into and out of the engine) means a change in momentum and thus a forward pushing force. For the jet engine, it increases the final speed of the outgoing air by also heating it by burning fuel.

So, how do you start a jet engine? It’s not the same as starting your car (but not completely different either). The main thing is that you need to get the jet turbines spinning first so that there is air moving through the engine. Then you can add the burning fuel to get the thing started. Here is a great video on how this works. Oh, this is why youtube is so nice—you can find a video on pretty much anything.

Pick lock with a paperclip

Oh, you missed this hack—didn’t you. When MacGyver gets into the old building, he has a paperclip in has hand. So, can you pick a lock with a paperclip? Maybe. You could use the paperclip to jiggle the lock pins, but you would need something to apply torque to the lock cylinder.

Here is a tutorial on lock picking—but don’t be a bad guy.

Break open door with a raft

MacGyver pushes open a locked door by filling a raft with water. Let’s start with the definition of pressure. Pressure is a force divided by an area.

Let’s start with the definition of pressure. Pressure is a force divided by an area.

P=\frac{F}{A}

You can solve this for the force.

F=PA

So, if you have a pressure (in the raft) it will produce a force equal to the product of the pressure and the contact area. The bigger the area, the greater the force. In fact, with just a small pressure you can get a pretty big force.

OK, this is from a previous episode but I still like it. Here is a demonstration in which I use the pressure from my lungs to lift myself. Yes, small pressure with a large area means a significant e force.

What about the water? Well, the water will give the raft more mass so that it doesn’t just push itself away from the door. If you want to open the door with air pressure, you would need to have something hold the raft agains the door.

Dart gun

I love this visual effect where MacGyver is looking around for stuff to build and it shows all the things he sees. In the end, he builds a dart gun that shoots morphine needles.

Really, I just want to talk about two parts of this build—the shooting and the injecting. MacGyver uses a propane tank to shoot the dart. This is the same as your basic potato gun. Compressed gas from the tank push the dart in the tube. The longer the distance of the tube, the greater the final speed of the dart.

For the injection, you can’t just shoot a needle into someone. You need to push that plunger on the back of the needle to get the drug into a body. That’s where the steel spacers come into play. When the front of the dart hits a person, it will stop. However, the mass on the back will want to keep going until a force slows it down. This force comes from the plunger—that means the plunger gets depressed and the bad guys get drugged.

Beam splitter

How do you make one laser look like many lasers? You need a beam splitter. This is exactly what MacGyver does to fool the baddies into thinking there are bunch of other good guys in the woods.

Basically, a beam splitter is a piece of glass. We like to think of glass as being transparent so that light goes right through it—and it does. That’s why we use glass for windows to see stuff outside. But light also reflects off glass. In fact, if the light (from the laser) hits the glass at an angle then you will get both transmission AND reflection.

It doesn’t even need to be glass. Here is a quick demonstration of a beam splitter with just a piece of clear plastic.

MacGyver Season 3 Episode 15 Science Notes: K9 + Smugglers + New Recruit

Dog nose

Dog’s are pretty awesome for smelling stuff. They have noses that are much more sensitive than a human and they are smart enough to be trained. Oh, also they are dogs—so that’s an extra bonus. Dogs can detect more than guns. When trained, they can sniff out drugs or even some humans with particular medical conditions. Pretty awesome.

Here is a nice PBS article on the science of dog noses. Oh, this isn’t actually a MacGyver hack. I guess that’s clear though.

Wall climb

Again, not a MacGyver hack. Instead, there is a scene in which Desi (yes, Desi is the new recruit) runs and uses a corner of two walls to climb on top of a storage container.

So, how the heck do you run up a wall? The answer is “friction” and “momentum”. Let’s start with friction.

When two surfaces interact, there can be a frictional force. This force is parallel to the surfaces and proportional the perpendicular force that pushes the two surfaces together (we call this the normal force). If you put a book on a flat table, you can feel that frictional force as you try to slide the book. If you push DOWN on the book while trying to pull it, the frictional force will increase.

Since you have a vertical wall, it’s possible to have an upward frictional force to prevent Desi from falling down. However, there needs to be a force pushing Desi INTO the wall in order to have a significant perpendicular force. Actually, try this yourself. Take that same book you had on the table. Now put it on a vertical wall and let go. Yes. It falls. There is nothing pushing the book into the wall so there is no frictional force.

Now for momentum. Momentum (represented by “p”) is the product of an object’s (or human’s) mass and velocity where the velocity is a vector (depends on both the speed and the direction). Momentum is important in its relationship to the net force on an object. Here, we have the momentum principle:

\vec{F}_\text{net} = \frac{\Delta \vec{p}}{\Delta t}

So, what happens when Desi runs TOWARDS a wall and pushes off? The direction of her momentum changes from towards the wall to away from the wall. This change in momentum means there must be a force on her. Yes, this force comes from the wall. The faster she runs towards the wall, the greater her change in momentum and the larger the normal force.

This means a large normal force also produces a large frictional force. The frictional force is high enough to prevent Desi from falling while in contact with the wall. In fact, it’s a large enough force for her to move UP the wall. Of course, she is also now moving away from the wall. This is where the second wall comes into play. Now she just does the same this with that other corner wall. Physics.

Smoke screen

MacGyver needs a distraction. He takes some gun oil (used to trick the dog) and pours it into the engine of a forklift. When the fork lift starts, it is now running with extra oil in the fuel. This oil produces a blue-white smoke that comes out the exhaust. Yes, you have seen this with cars. It’s a bad sign that there is oil leaking into the engine cylinders.

The next thing that MacGyver does is to cut the fuel line. This pours extra diesel onto the hot engine. Theoretically, it could catch fire. Theoretically, this fire could cause an explosion. In theory.

DIY dog whistle

Yes, you can indeed make a whistle from a stick. Some sticks are easier than others—but still…

What makes a dog whistle different than a whistle? It’s really just the fundamental frequency that it blows. A normal whistle has a lower frequency that human ears are good at detecting. The dog whistle has a much higher frequency that most humans can’t hear.

Oh, what about the plastic bag? Yes, MacGyver gets a plastic bag and attaches this to the whistle. This makes an improvised bellows. The idea is that you can fill it up with air and then push the air out at a greater rate than just blowing. It makes the whistle louder than normal.

RFID detection

Cody (the dog) has an RFID chip in him. The basic idea behind a passive RFID is that you can excite it with a radio wave such that it transmits some data (like an ID). Oh, but you have to get pretty close for this to work. Here is a nice RFID tutorial.

Now for the MacGyver hack. In order to find Cody with his RFID, they need two things. First, they need a method to activate the passive RFID at a long range. To do this you need lots of power. That’s where the AM radio station comes in. If you use a nearby radio transmitter, it could activate a bunch of RFID tags. This is fairly plausible. No, you wouldn’t “hear” anything—it would just broadcast a particular frequency that the RFID uses.

The second thing—something to detect the RFID signal from a range. That’s why you need a satellite dish. The parabolic dish reflects weak radio signals into the detector. Of course this only works if you are pointing it in the right direction. So, you need to sweep this over some area until you get a signal. Once you find the dog you want, you have to use the dish to zero in on the location.

Disabling a car

What can you do to prevent a car from driving? Yes, there is the classic banana up a tail pipe trick (from Beverly Hills Cop), but how about something different?

OK, I admit this is a bit of a stretch. However, if you can make some sort of electromagnetic pulse device then it can interfere with the car’s electronic system.

That’s “essentially” what MacGyver does here. Let’s just leave it at that.

Foam fire extinguisher

How do you put out a fire? One way is to remove oxygen from the fire. Without oxygen, the fire can’t burn. This is essentially what a carbon dioxide fire extinguisher does. It shoots out carbon dioxide gas which displaces the oxygen and the fire goes out.

You can make a foam-based fire extinguisher that essentially does the same thing. The only difference is that the carbon dioxide is trapped in the foam. This means that you can cover some stuff with the foam and it should put out the fire.

Now for the fun part. You can make fire extinguishing foam with three things: vinegar, baking soda, liquid soap.

When you mix baking soda and vinegar, it produces carbon dioxide. If you add soap to the vinegar, then it also bubbles. This is not too difficult to try (but it can get messy).

MacGyver Season 1 Episode 17 Science Notes: Ruler

Propane tank flame thrower

Take a propane tank and bicycle tube. Cut the bike tire to make it a hose and connect it to the propane tank. Use a road flare to light the gas—boom. There is your flame thrower.

Oh but wait. It’s just a dream. Bozer’s dream. The flame thrower wasn’t real anyway.

Listen in on a landline phone

Who uses a landline now anyway? Oh well. They want to use a landline then it’s possible to listen in. Actually, this isn’t even that difficult. Check it out.

Here is another version.

You just need a capacitor and maybe an inductor. You could grab these from a radio or something like that.

But wait. I made a mistake. While going over this hack, I said something like this:

“Yeah, this is pretty easy. Just get the capacitor and earpiece (or radio) and then tie it into the wiring box”

Here’s what that looks like.

I just want to point out this small mistake (that you would never notice) just in case you saw it. You don’t actually “tie” the lines—that’s just a term we use in circuits to mean “connect”.

Bomb radius calculation

There’s a bomb in the truck. Where should you park it so that no one gets hurt? Yeah, this is a tough calculation. However, tough has never stopped MacGyver before and it won’t stop him now.

Here is my rough calculation and explaination.

Bombs are complicated. But usually it is the pressure produced by the explosion that will get you. We can come up with some pretty useful models to calculate their impact. First, there is the Hopkinson-Cranz Scaling Law (this is a real thing). With this law, the acceptable distance can be calculated based on the explosive weight.

\mathrm{Range} = (z)(\mathrm{weight})^(1/3)

In this expression z is a factor that depends on the type of distance with 14.8 being the distance factor for a public traffic route. That means that 2 kilograms would need 18.6 meters (60 feet).

Infrared face jammer

OK, it doesn’t actually jam your face. That would be weird. MacGyver wants to prevent the security cameras from recognizing their faces. So he takes some infrared TV removes and pulls out the IR LED lights. Normally these flash on and off so that the sensor on the TV can “see them” but humans can’t.

He mounts these IR LED lights on some sun glasses with a battery to power them. When a security camera sees the face, it just gets blinded by the IR light since many video cameras can also detect IR.

If your phone camera doesn’t have an IR filter (most now do) then you can actually see the light flashing on a TV remote by pointing it at your phone.

Oh, so this could really work. It just depends on the type of video cameras. Some people even put stuff like this on their car license plate so that police cameras can’t see them.

Car jacking

How do you open a locked car door? One way is to jam a wedge into the door. This will pull the door out just a little (by bending it) so that you can get a stick in there. The stick then can be used to push the “lock” button.

In this case, MacGyver uses something for the wedge—maybe a shoe horn or a door stop. Then a monopod is extended to click the lock button.

DIY soldering iron

You might have missed this one. But as MacGyver is building his stuff for the last mission, he needs a soldering iron. He takes the heating element out of a hair dryer and connects it to some stuff. That works.

Fake noses

Need a disguise? How about DIY latex to make a nose? Yes, this seems plausible. Here’s how to do it.

DIY keypad cracker

MacGyver makes a quick circuit board that can crack a keypad by using a brute force method that goes through all the combinations. This is from a different episode, but it’s the same idea.

If you want to play with one yourself, here is an online version of the code.

Oh, here is the code on trinket.io.

DIY police radio

Well, it’s just a radio. MacGyver needs a speaker and a transmitter. Really, a radio transmitter is essentially the same thing as a radio receiver—OK, not really but sort of.

Instead of going over the way MacGyver did it, how about a real actual radio you could build yourself? Here is a spark gap transmitter from simple parts (and awesome).

Here is a more detailed explanation of the spark gap transmitter from one of my WIRED posts.

MacGyver Season 3 episode 12 Science notes: Fence + Suitcase + Americium-241

Toothpick in grenade

It’s not a super Mac-hack, but it works. The only thing MacGyver does is to put a toothpick in place a grenade pin. It only works for a little bit before the grenade explodes. However, the physics discussion is pretty good. Let’s go over some of the terms.

  • Tensile strength. This is essentially the maximum force a material can withstand when being pulled apart. Just imagine a rope—how hard can you pull on the rope before it breaks. That would be the ultimate tensile strength. Yes, wood has a pretty high tensile strength.
  • Compressive strength. How hard can you squeeze the thing before it fails? Something like concrete has a very high compressive strength, but not so much with tensile strength. Wood could have a good compressive strength if it’s wide and short. Long skinny boards of wood tend to buckle.
  • Sheer strength. This is the maximum force an object can withstand when two forces are pushing in opposite directions but not directly at each other. Think of scissors.

What is a dirty bomb?

This is another non-hack. However, I just want to describe the difference between a nuclear bomb and a dirty bomb. A nuclear bomb uses a nuclear reaction (usually started with conventional explosives) to make a massive boom.

The dirty bomb is NOT a nuclear explosion. Instead, it uses conventional explosives to spread radioactive material around. It’s dirty.

Electromagnet

MacGyver builds a strong electromagnet to move a bolt inside a locked door. Yes, this is possible. You would need a strong electromagnet—that means high electric current and thus thick wires. You also need a fairly beefy battery to get this much current.

Oh, one possible problem. If the bolt is ferromagnetic (steel) and so is the door, then it’s going to be difficult to get that bolt to move. However, if the door is aluminum or some type of non-ferromagnetic material then this would work.

Wall walk

There are two methods to get over the pressure sensitive floor (they end up not using this though). There is a wall-walking stilt method and a rolling sled method. Both have the contact point with the wall at an angle—this is needed in order to work (because of physics).

Let me just start with a setup that would only barely work. Here is a view of a person using completely horizontal stilts along with the forces on the person.

The first problem is that the stick the reaches across the hall would have to fit perfectly. The harder it is pushed against the wall, the greater the frictional force. And it is this upward frictional force that balances the weight pulling down.

The second problem is with these horizontal arms. When they attach to the person, there is no upward force. This would be like trying to hold a rope with a weight in the middle perfectly horizontal. It won’t work.

Here is a better option.

This setup fixes both of the problems. The sticks can be longer than the hallway (and not fit perfectly) and there is now an upward component from the wall that helps support the human.

Mercury Switch

What is a mercury switch and how can you build something similar? Here, I made a video for you.

Smartphone Radiation Detector

MacGyver uses some smartphones (as usual) to detect radiation from the dirty bomb. This is essentially real.

A smartphone camera has a sensor that is normally used to detect light. However, this same sensor can be set off by other types of radiation—like the stuff that is produced by radioactive stuff.

In order to actually detect this radiation, you need to block the light from getting to the camera—electric tape over the lens will do the trick.

But wait! There is a real project that uses normal human smartphones to detect cosmic radiation. Check it out—the CRAYIS Project. https://crayfis.io/

Rolling Tire Bomb

Yeah, mixing stuff and make explosions. The end.

MacGyver Season 1 Episode 8 Science Notes: Corkscrew

Remember, I’m just going over the MacGyver hacks with science stuff in them.

DIY Blacklight

This one is fairly legit. MacGyver is in an escape room and needs to find a blacklight to read some hidden words on the wall. He says it would be easier to build a blacklight than it would be to find it.

Here is MacGyver’s build. Use a smart phone LED light and an old floppy disk. In theory, this could work. Here is the short answer: most white LED lights work by having an ultraviolet light with a fluorescence coating to produce white light (which is the way the old school tube-like fluorescent lights work). This means that the white LED also produces UV light (also called blacklight). You just need to block out the visible light—and that’s where the floppy disk comes in. If you take the actual disk out of the floppy, some of them block visible light.

I actually wrote a WIRED post on this—here it is.

https://www.wired.com/2016/12/make-uv-light-phones-led-flash/

Fluorescence of stuff on the wall 

The second part of this hack is to use the DIY UV light to read the stuff on the wall. Here’s how that works.

Electrified stair rail

A bad guy is getting away and running down a stairwell. MacGyver pulls some wires out of a wall light and touches one of the wires to the rail and the guy gets shocked and falls.

Would this work? Maybe. In order for the guy to get shocked, there has to be a complete electrical circuit that passes through the dude. That means the current would come out of the wall, go to the rail, go to the guy, go OUT of the guy, and then back to the wall.

In order to get through the guy, he would have to be grounded and the rail would have to NOT be grounded. I suspect that building code requires a rail to be grounded for safety—but you never know. In order to get the guy grounded, he would have to stand on conducting ground (like metal) and have terrible shoes.

But still, it’s at least possible.

Hacking magnetic lock

MacGyver is trapped in another room—with essentially nothing in it. He grabs some wire out of the ceiling panels can fishes out the wires for the security pad. Then he manually enters the keypad code by connecting wires.

OK, this could work. However, it if it’s a legit security pad it would probably be harder to hack.

Wine bottle rocket

MacGyver takes some wine bottles, dumps out some of the wine and recorks them. Then he pumps them up and let’s the cork pop out. Now it’s a water bottle rocket.

Here is the launch in slow motion.

Of course like many MacGyver hacks, this is real. The only problem is that it would take a normal person a few minutes to set up and not a few seconds.

Radio jammer

MacGyver needs to take out some remote controlled guns. He grabs a CB radio from a truck and hooks it up to a large power supply. This broadcasts enough static to jam the radio signal to the guns.

Let’s go over the details.

  • Could he get a CB out of a truck? Yes. Easy (but it wouldn’t be as quick as he does it).
  • Could he hook it up to a power supply? I think he used the power lines to some metal crusher. This probably wouldn’t work. The CB runs on DC current and the big power is probably AC. Also, it probably expects 12 volts.
  • Would this jam the signal? Here’s where he might get lucky. If the guns run on the same channel as the CB —it would work. If the power supply messes up the radio so that it just somehow broadcasts on a bunch of frequencies—it would work.

So, it’s possible.