Sorry for the delay in science notes. There were things that got in the way.
Block and Tackle
I don’t really like calling it that. A better term is a compound pulley. But the key to all of the simple machines is force vs. distance. If you increase the distance over which you apply a force, you can get a larger force output of the machine over a shorter distance. That’s exactly what happens with a “block and tackle”.
But basically it’s alcohol oxidase with some other stuff added. When mixed with alcohol, this makes aceteldehyde—the main thing that causes hangovers. MacGyver could get alcohol oxidase from alcohol test kits.
Note: I’m not a biochemist, I got this info from my brother (a biochemist).
Don’t make this stuff. But it is possible. Actually, I’m not even going to include the link.
Using a hammock as both a ladder and a body sling? Yup, that’s good. Using a chain as a DIY car boot. That works too. Not much to explain, but I think both of those hacks are great.
In order to knock out everyone in the room (including himself), MacGyver throws some chloroform in a container into a fire. It explodes and everyone gets knocked out. Sure, this would be tough to do in real life—but it’s a least plausible.
DIY Arc Lamp
Wait. There wasn’t an arc lamp in this episode was there? Nope. It get cut out of the beginning. However, I made an arc lamp anyway as part of my DIY videos. It’s awesome.
Oh, it has a built in timer—a leaking bottle of water. Here is the shot from the show.
And here is my rough sketch.
Oh snap. That pay phone is broken. Wait! What’s a pay phone?
MacGyver fixes the missing headset by using two speakers from the car. One speaker is used for the speaker and the other speaker is used for the microphone.
It’s actually pretty cool, but most speakers can be used a microphone. The normal speaker is basically just three parts:
A coil of wire.
Some type of surface area to push air.
The coil of wire is connected to the speaker surface. When current is run through the wire, the coil makes a magnetic field. This magnetic field from the coil interacts with the other magnet to either push or pull the surface of the speaker. This in turn pushes the air into compressions—and it is these compressions in the air that make the sound.
For a microphone, the reverse happens. Compressions in the air push the surface. This moves the coil closer (or farther) from the magnet. This motion changes the magnetic flux (via Faraday’s Law) which induces a current in the coil. This current is then recorded as an audio signal.
Don’t believe me? You should try it. Oh, make sure you use a speaker like this:
OK, there are some weird things in these old phone head sets. I think they have to use super low resistance microphones and speakers since the power comes over the phone line. But still, this is very plausible.
Break a chain with handcuffs
Oh, and a steel rebar thing. MacGyver loops the handcuffs around the chain and then puts the rebar through the cuffs and twists.
With a longer metal bar, you can get a high torque on the chain. This should break the chain—at least as long as the hand cuffs are stronger than the chain.
Don’t break into people’s houses. Oh sure, there are lots of ways to get into someone’s house. Think of a locked door as a social norm. People agree to not go past that locked door (or window)—even though they probably could.
In this case, MacGyver gets in through a window. In some cases, it’s possible to use the friction between your hands and the glass to shake the window up and down. This can slowly force the window lock into the unlocked position.
Detecting Metallic Ink
Here is another one that seems crazy, but it turns out to be not so crazy. MacGyver builds a detector to find some hidden cash. Yes, it’s indeed possible to detect the change in magnetic fields due to metallic ink in US currency.
But you have to be pretty close—and really it would only work to determine how many bills are in a container. However, there’s still a chance this could work.
In this case, MacGyver uses a hall effect sensor along with a speaker to create an audio-based system to search for the money. In the show it works like a metal detector—but it’s not a metal detector since the hall effect probe detects magnetic fields.
I’m not sure I should go over all the details of a hall effect sensor, instead I will just like to one of my WIRED posts on the subject.
But what about the speaker part of this build? Well, it is indeed true that you get a voltage signal out of a hall effect probe. If you run this into an audio amplifier, you probably won’t get any sound because you would need a changing magnetic field. But it seems likely that you could have the hall effect probe voltage control and audio tone.
Anyway, here is my very basic sketch for this detector.
Distraction with Streetcar Sparks
MacGyver grabs a chain and throws it onto the wire that the streetcar runs on. Sparks fly and cause a distraction.
The New Orleans streetcars are electric powered trains. They get power from two lines. There is a line above the car and the other is in the rails (at least I’m fairly sure that’s how it works). So, just touching a wire at the top with a conductor wouldn’t do anything. If you had a chain running from the top wire down to the ground, that would cause a short circuit and probably melt the chain. It would be bad.
Of course there is a way to get this to work. What if MacGyver throws the chain over the power line so that the chain hits both a power line AND a support pole? I imagine there is an insulator keeping the power line isolated from the ground, but getting that chain to make a connection would do the trick.
Infrared Chemical Tracker
MacGyver finds the following stuff:
Selenium powder (they make solar panels with this stuff)
Cadmium oxide – the stuff from the inner part of a battery
With this he is making a type of quantum dots.
Oh, I forgot to say something—quantum dot tracking dyes are real.
The idea of the quantum dot is that it is a very small particle that emits a particular frequency of light. If you “excite” it with an ultraviolet laser, it can emit infrared radiation that can be detected with a drone camera. Cool.
So, for MacGyver’s case—they skipped the whole UV light part. But still, this is another great example of something that seems crazy but is in fact based on some real science. Science is crazy.
MacGyver is a show. It’s fictional. It’s not real. Some of the things are BASED on real science (and some of them are legitimately real). But it’s still a show. It’s like Star Wars—but without the light sabers. Everyone knows there is no way you could even THINK of making a lightsaber with science, but we like them anyway.
So, even though some of the hacks in the show are only slightly plausible, there is still an element of truth in there somewhere. Honestly, I’m just happy that anyone even cares to make a show that even considers real science. Thanks Peter!
OK, now for this episode’s MacGyver hacks.
Tracking a vehicle with CO2 sensors
So, there’s this runaway robot car with guns and the Phoenix team has to find it. It’s got stealth technology, so they can’t find it from above. That leaves MacGyver, Riley, and another girl in a car to track it down.
The idea is to use the carbon dioxide emitted from the robot. Yes, it’s a hybrid vehicle. That means it has an internal combustion engine. These things take in gasoline and produce energy along with carbon dioxide and other stuff. Oh, it’s this same carbon dioxide that contributes to global warming and climate change—just to be clear.
The plan is to have two CO2 sensor sticking out of the car on tree branches (now you get the title). The sensors are connected to the dome light in the car so that they can tell which direction has a stronger CO2 and then they know which way to turn.
Here’s what it looked like.
Here is one of my diagrams (this went through quite a few iterations).
Here is one of my earlier diagrams—it was slightly more realistic using some MOSFETs for amplification and everything.
In the end, the CO2 level in the air from a vehicle is quite small. I think it would be seriously implausible to use two detectors to determine the direction to the robot. So, I will go ahead and give this is “real score” of maybe 1.5 out of 10. Here are some other hack scores—in case you are curious.
The basic idea is to beam high power radio waves at a vehicle to fry the electronics. In this case they say it just drowns out the network so that Brutus can’t communicate and it stops.
MacGyver builds this RF gun using a transmitter on the truck and a satellite TV dish. In order to get the power high enough, he uses the car battery.
OK, now for a homework question. Assuming the van they are in has a normal style car battery, how much current does the RF gun use so that it drains the battery in 5 minutes? Some estimations might be required.
Hotwire a car
I’m pretty sure I talked about this in a previous post. Modern cars are really tough to hotwire—good thing they found an older camero.
Final hack of the show. MacGyver uses his phone and a belt to pull and bend the vents on Brutus. He needs a space big enough to fit a USB stick through. It’s funny because MacGyver kills his own phone and not Jack’s.
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.
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.
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.
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.
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.
Remember when I used to start off these posts with some type of introduction? Yeah, I remember that too.
So the generator is out. Apparently the problem is the fuel pump. MacGyver isn’t going to fix this generator, he is going to walk Zoe through the steps to do it.
The replacement for this fuel pump is a DIY peristaltic pump. This type of pump essentially pushes a fluid through a tube by compressing it (it has to be a flexible tube). The nice thing about this pump is that the fluid doesn’t interact with the mechanics of the pump—that could be important for some liquids you don’t want to get contaminated.
Here is a nice DIY version.
But wait! Would this work with a gasoline powered generator? I think it could work. The peristaltic pump doesn’t exactly give a constant flow of fuel. However, if there is a reservoir somewhere after the pump that could stabilize the fuel flow to make it work.
Here is the MacGyver version.
How do you build a really long device to grab some stuff you can’t reach? What if you just want to “poke” it instead? You could create a poking device. Something like this.
I bet you didn’t think there was a connection between MacGyver and Friends? Did you?
Tilting the Ship
The giant grabber didn’t work. Instead of grabbing the containers, what if the containers came to Zoe instead? Yes, the idea is to get the ship to tilt so that the stuff rolls to her. But how do you tilt a ship?
It’s not as simple as you think. If you add more mass to one side of the ship, it will indeed shift the center of mass. But this will make more of that end of the ship underwater and produce a greater buoyancy force. The amount of buoyancy force depends on the exact volume of water displaced. Honestly, it’s a pretty tough problem. Of course that doesn’t stop me from doing it anyway.
Here is my calculation.
Even though it’s tough to see, here is MacGyver’s calculation.
This is the part that feels most like the Apollo 13 movie. Here is a similar box fan filter.
Resin Water Seal
There is a door that needs to keep out water—but the seal was destroyed by fire. I can’t recall the exact chemical formula we used, the main idea was to use something that expands when heated.
There should be plenty of options using chemicals on the ship.
The basic idea here is to use a walkie talkie (I love that name) to activate the water sealing putty. It’s really not too complicated to turn a radio into a detonator. The idea is to remove the speaker and replace it with a very thin wire.
When you send a signal to the detonator, instead of playing a sound it will run current through the wire that gets hot. This by itself might not be enough to activate the putty, but you could add on some match heads or something like that. The hot wire would ignite the matches and those would activate the putty.
Of course in the end, Zoe had to find another way to activate the putty and save the ship.
Brute force is a real thing in both science AND in code breaking. The idea is that instead of spending time trying to solve a problem, you just try all the possible answers until you get it right. Yes, you’ve done this before. Remember that silly online quiz that you had to take in that one class that one time? The quiz had 5 multiple-choice answers and you could submit as many attempts as you like. Here’s what you did:
Try answer A. Nope. That didn’t work.
Try answer B. Nope. That didn’t work.
Try answer C. Boom. That worked.
That’s brute force. But really, you should have just read the book and tried to figure out the right answer without brute force.
In code breaking, a brute force attempt just tries ALL the different combinations. Sometimes this can work—but sometimes not. Take the iPhone for instance. After you incorrectly try a pin number to get in, it makes you wait some time before the next attempt. The more failures, the longer the wait. Brute force doesn’t really work for the iPhone.
But this door. This door doesn’t have that feature. So MacGyver build this device that just tries all the codes. Actually, it looks pretty awesome.
This brute force code breaker is something that you could build yourself. Here is a short video showing how this would work. I didn’t use pencils—but lights instead (to make it easier to build) and it uses a Raspberry Pi (a super cheap tiny computer that is super awesome).
Oh, if you don’t have a Raspberry Pi, you can still try this code out with an online simulator. Here is a video that covers that.
Let’s talk about stealing cars. DON’T STEAL CARS. Stealing is bad. Anyway, it’s pretty darn tough to steal a newer car. Here is a great video that goes over the three ways you SHOULDN’T use to steal a car.
However, in this case MacGyver uses a trick. Some newer cars don’t use a key. They instead have this fob. You just get in the car, the car detects the fob and presto. It starts when you push a button.
The hack is basically a key fob extender. One person uses a small radio device near the car owner and the other person has another radio device near the car. The devices basically trick the car into thinking the fob is right there and it let’s you start. Yes, this is a real thing.
DIY Tear Gas
Yes, you could probably make some tear gas—especially if you are in a lab with tons of supplies. Let’s just leave it there. Is that OK?
Hood from a CD-ROM and Hoagie Foil
I work in a building with chemists. They are mostly nice people even though I’m a physicists. But whatever. The one thing that just about all chemists use—the hood. What the heck is a hood? It’s basically a big box with a window that they have in chemistry labs. Inside the hood is a fan that blows air up and out of the building. By putting stuff in the hood, you don’t have to worry about fumes and stuff since they get pushed out of the building.
But there is something kind of sucky about hoods. They mess up the pressure in a room. If the hood blows air out of the building, then new air has to come into the room. This makes the inside of that room a little bit lower in pressure. You can feel it when you open the door.
I thought for sure that I had a picture of a chemistry hood—but I can’t find one. Sorry.
OK, in this case MacGyver is in a room and needs a hood to vent the VX gas. He opens a sewer pipe (I think that’s what it is) and then just needs a fan to blow out the air (and gas). He uses the motor from a CD-ROM drive (who uses those things any more?) and builds a fan out of a CD. To seal it up, he uses hoagie foil. Title of the episode.
MacGyver and Jack use a large blanket to hold up in front of them in as they move slowly down a hallway. The idea is to trick the motion sensor so that they can steal something.
There are several different types of motion sensors. If you have one in your house for your security system, it’s probably a PIR—Passive InfraRed sensor. This basically works by detecting the infrared radiation that your body emits because of its temperature. For this type, you can just block the IR light coming from your body—at least in theory.
But could the sheet method actually work? Yup. This was tested by the MythBusters.
Hanging boot to fool painting sensor
They need a painting off the wall. It has a sensor that detects if the painting is lifted up. MacGyver hangs a boot on the sensor to mimic the weight of the painting.
It’s basically a version of Indian Jones stealing the idol at the beginning of Raiders of the Lost Ark.
Chair to block a door
What happens when you jam a chair under a door handle? Sometimes this will indeed prevent the door from opening. As the door starts to open, the chair rotates to a more upward position. However, the door handle stops the back of the chair from moving upwards. This means that that bottom of the chair pushes MORE into the floor. The basic model of friction says that the frictional force is proportional to this force pushing into the floor.
This trick can sometimes work.
Zip line from a curtain
MacGyver takes a curtain and cuts it into strips. Then he uses these strips to make a rope. The rope makes a zip line to send the stolen (borrowed) painting over the fence so they can escape into the pool.
Turpentine and packing peanuts
Yeah, mixing stuff together and then lighting it on fire can make a big mess. Let’s just leave it at that.
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.