- I saw this video on Twitter with over 5 million views,
and then again on YouTube with nearly 1 million views.
Basically, this guy modified his cell phone case
with propellers to take selfies, which is awesome.
My only issue with it is that it's not only fake,
but it's a scam, which I'll explain in a minute.
But as for it being fake,
the first clue is that these are three-volt,
seven-millimeter microbrush motors like you see here.
If you attach one to a beam like this
and turn it on at full throttle, you'll see the most weight
that it can lift is six quarters, or about 30 grams.
The cell phone in the video
with all the flying gear attached would weigh
about 300 grams, and since drones are typically designed
to hover at 70% max thrust,
you would need at least 15 of these motors
to do what he did.
But you know, this just doesn't look as catchy.
In fact, we recreated the exact setup he used
in the video and turned the motors to full throttle
and this is what happened.
Here it is in slow-mo, and as you can see,
there's hardly any difference than if you don't turn
the propellers on at all.
So I'm gonna show you how this scam artist somehow manages
to break the laws of physics four more times
in this three-minute video.
And then because obeying the laws of physics isn't optional,
we're gonna call up fellow YouTuber Captain Disillusion
to see if he can help a spot any signs of special effects.
And then with my buddy Peter Sripol,
I'm gonna show you what it would take
to actually build a flying selfie phone case,
and then I'll put all the details
on a new site I built using wix.com.
But before I do any of that,
let me first explain why this is a scam
and not just a harmless fake video
for meaningless internet points.
With this many views and an astounding 80% like ratio,
which means most people probably didn't realize it was fake,
it's a statistical certainty
that some young, aspiring engineer
actually tried to build this themselves.
Worse than their parents' phone dropping like a rock
and breaking, this might have been his
or her first experience at making something.
But how, you might ask,
would they know what components to use?
Well, here in the description,
Amazing maker was kind enough to put links,
Amazon affiliate links.
You can tell by the URLs.
So he is making money off the crest dreams
of aspiring engineers without enough experience yet
to know that this is total BS,
and aspiring engineers are my people
and you don't mess with my people.
(gun cocks)
Let's do this.
(gun fires)
The second gratuitous violation
of physics comes in this scene.
Force of gravity always points down,
but helicopter spinning blades create a force perpendicular
to the blades themselves.
So if you want to hover, you need to be level
so the forces will cancel out and you won't move.
If you tilt forward and then break the thrust force
into its x and y components,
you suddenly have an unbalanced force that will move you
in that direction.
In essence, that's how helicopters move forward,
by tipping forward.
In other words, it's physically impossible
to hover in an orientation like this.
The forward thrust component is unbalanced,
and it would have to move the phone forward.
The third major issue
is the Arduino-compatible circuit board he chose.
It's the same board here,
and it's supposed to be the brains for the drone.
Yet this specific model of board doesn't come
with any sort of gyroscope or accelerometer.
Here's why that matters.
If you've ever tried balancing something on your hand
like this, you and your body were creating
what's referred to as a closed loop feedback control system.
So if it starts to tip over,
my eyes relay that to my brain and my hand says,
"Hey, I'm no longer feeling the weight just up and down.
It's also pushing my hand this way."
And so my brain takes all that information
and responds by telling my hand to move this way
at a specific speed in order to compensate.
So to keep this thing balanced, there's this continuous loop
of quickly gathering information,
and then making real-time adjustments.
And closed feedback loops are used all over in engineering,
from the simple case of a thermostat
that continuously checks the air and turns
on at a certain temperature, to dartboards that update
their position 200 times a second
to get a bullseye every time.
(bell dings)
To machines that are abused,
and most certainly for anything that flies and needs
to stay in the air.
The fact that his board is missing a gyroscope
and an accelerometer means there's no way for it to tell
if it's starting to rotate or to fall in any direction.
It's the equivalent of trying to balance the board
wearing a blindfold and an oven mitt.
You have no idea what adjustments to make
to keep things balanced.
(cat meows)
Which is the perfect lead-in
to the fourth major physics flaw.
Notice how he attaches these motors
and rigidly fixes them to the phone with double-stick tape.
This means if you start to tip forward,
you have no way to self-correct the phone orientation,
and it would just turn into a nose dive.
If you only have two propellers in this configuration,
they both need to be able to rotate with respect
to the phone in order to correct for movements
in all six degrees of freedom.
For example, if it starts to tip forward,
you could rotate them both back like this
to correct for that.
Or if the wind is trying to spin the phone this way,
they could assume this configuration to counter that.
To return to our balancing shovel analogy,
by fixing the motors directly to the case,
you lose your ability to even make corrections.
So not only do you have no idea where to move,
but your arm is locked out from making adjustments anyways,
which makes it literally impossible to balance.
(shovel clangs)
Ow.
And my final physics issue with this video
is one of acoustics.
This guy proposes using it as a hands-free way
to watch your favorite, super hip music videos,
conveniently dubbing over the audio here.
(upbeat music)
(singers singing in foreign language)
For reference, this is what an episode of "The Office"
would sound like on a phone at full volume.
(actor talking)
(propellers buzzing)
And don't forget, you would actually need
13 more motors than this,
so it would be at least six times louder.
So now we've thoroughly established
a multitude of physical laws have been broken,
let's find out exactly how he faked it.
And to do that, I've arranged a video call
with the undisputed heavyweight champion
of debunking fake videos using special effects,
Captain Disillusion.
- Make sure to get it as flush as possible
against your skin to minimize folds
that might make it hard to chroma key out, like this.
(Mark clears throat)
Nice and tight.
Mmm.
- Captain!
- Oh, hi, Mark.
Mark Rober! You weren't supposed to call yet.
- It's two o'clock.
I'm actually even five minutes late.
- Really? Well then.
(objects whirring)
How can I help you?
- Did you not even watch the video I sent?
- Ah, yes, of course.
The mobile drone video.
I've analyzed it thoroughly, Mark,
and my conclusion is it's totally real.
- Seriously?
- Yes, everything except
for the mobile drone part, that's fake.
If you look very closely,
you might just be able to make out the huge, shadowing mask
on the side of the phone,
visible in every shot of it flying.
The creator must have been in a real hurry
because it's so messy.
Here, it cuts off the edge of the phone.
Here, the tip of his finger.
And here, it reveals the thing
it's supposed to be hiding, a rod.
It's narrow and light colored,
and probably attached with the same mounting tape
he used to tack on all the other gadgets.
That's why he's able to grab
and adjust the phone in this shot.
By the river, the mask hides not just the stick,
but the whole person holding it.
Look closer.
On this side, the real-time water,
and on this side, a still frame from an empty version
of the shot.
And if we track the phone's position and rotation,
we can easily reverse engineer
exactly how the stick puppeteer did,
rotating mostly from the point where it was held.
- Wow, that was very impressive, Captain D.
Thank you for taking the time- - My favorite part
of this whole thing is the audio.
The tiny propellers must have made
so little noise at a distance,
it didn't give a proper drone vibe.
So the hoaxers recorded the sound of the motors up close,
and reused the same clip in every scene,
complete with their muttering voices in the background.
(drone whining)
- Awesome.
Well, thanks again for- - But even more impressive
is the number of posts, messages,
and tweets presumably from people
with functioning eyeballs asking me
if this painfully obvious edit is real, over and over.
- Okay, Captain, well, take care.
I've gotta go back to my-
- Even you, Mark!
How could you do this to me?
How could you do-
- He's such a joker. (laughs)
So it's fake, and now you know exactly all the reasons why,
but it's still a really interesting idea.
And I was curious what it would look like if you actually
built one of these using less special effects
and more practical engineering.
So naturally, I called in my buddy, Peter Sripol
whose qualifications include building
his own electric plane from scratch,
and he immediately got to work.
(bright music)
Turns out if you take two brushless motors,
two electronic motor speed controllers,
a flight controller that actually has a gyroscope
and an accelerometer integrated,
a 3D-printed frame, and two servos to articulate the rotors,
a radio transmitter for a remote control,
and a four-cell lipo battery,
and then you put them all together,
it actually works.
(propeller whining)
(machine clattering)
Kind of.
We had to do a bunch of test flights
to calibrate that feedback control loop
we talked about before.
So if we notice the drone is either undercompensated
or overcompensating when it starts to fall in a certain way,
we tweak the response sensitivity
in between flights until we get to the sweet spot.
And I should mention, remember how the motors
from the fake video could barely lift only six quarters?
Well, if you properly size them for the task at hand,
they should be able to lift 150 quarters.
And so once we felt like we had it in pretty good shape,
we took her out for the maiden test flight.
(gentle music)
(camera shutter snaps)
(gentle music)
In our defense, it was a little windy out there,
but as you can see, it could be pretty wobbly at times.
The truth is, a bi-copter like this totally works.
It just isn't a great design choice.
The reason pretty much all camera drones are quad-copter
is because they're much more stable due
to a larger footprint shared between four motors.
And by getting clever with a throttle speeds,
you can move in all six degrees of freedom
with no moving parts.
So there you go, with solid engineering,
you don't need hidden rods or masking and rotoscoping,
and Sir Isaac Newton
can once again comfortably rest in his grave.
So the moral of the story
is just don't cheat and lie and scam.
I actually considered going a little easier
on Amazing maker, but then I happened to scan
some of his other videos,
like this knee brace that charges your phone
and even powers this flashlight as you walk.
In theory, I'll skip the details, but in reality,
this system would also never work as shown,
which is why if you rewind that and stabilize on his hand
in the pocket you see him click a hidden flashlight switch.
Thanks for watching.
(bright music)
(children yelling)
(snowballs striking)
(Mark yelps)
More tape!