A DIY enthusiast built a complex robotic system to cut his own hair, documenting the challenging engineering process, the numerous setbacks, and the surprisingly artistic, albeit imperfect, final result.
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so i look very silly in this machine and
the reason i'm in here
is that the longer i go without cutting
my hair the younger i look if you base
my age on the youtube comments on my videos
videos
i'm somewhere between a 14 and 16 year
old boy and the other thing that people
are saying is that i look like the
reference model for the lego minifig i'm
not really seeing the resemblance but
it's time to cut my hair i would rather
not have someone cut my hair who's
touching 100 other people's heads all
day long
so i built this robot and it is a hair
cutting robot
it's going to cut my hair the hard way
using scissors no trimmers or any easy
mode like that
and i think it works so i don't know
because i still have all my hair i
haven't tested it yet
and i'm a little bit worried because the
initial trials with the dummy didn't go
totally smoothly but
i think i've mostly worked out those
software bugs i did a quick dry run
just a little bit before this just to
see if everything was working without
cutting and it had this other problem of
ripping my hair out wow
i've fixed it now the fingers clamp a
lot less hard than it did before i'm
glad i tested that and even if this
thing gives me a terrible haircut i
still feel like i've won
how many people have a robot made
haircut it's basically art
my prediction is that it's going to give
me somewhere between completely
terrible and a 5 haircut well i've put
this off as long as i possibly can
so this is the first haircut that it's
ever going to attempt
[Music]
so how about that weather i don't know i
mean i guess it's warm out
oh well cool you can tell from my face
that i wasn't sure if it was completely
wrecking my hair or not i honestly
was not sure if this was gonna work
because it was a hard problem
so the hard part even with the robot is
handling the hair the hair wants to go
all over the place and what you need to
do is separate out
a very local chunk of hair and you don't
want to have any other hair trapped in
that chunk and so that's what a lot of the
the
combing and finger work that stylists
are doing it's to separate out the hairs
i knew in my heart that trying to build
a robot that works like a stylist to
separate out hair was
a bad idea i still tried to do it that
way initially
before i go way off the deep end into
the details i need to take care of just
a little bit of housekeeping
so i'm 90 sure what i want to build next
i want to hit a baseball really far
like really far it just sounds like good
old-fashioned fun to me
i'm excited because i found the perfect
thing to put some extra pep into my swing
swing
this is a device which shoots nails into
concrete using
basically bullets so that's cool
i'm super aware of the safety
considerations here i'm going to do this
very carefully in a very safe way
so no need to tell me to be safe in the
comments but if you want to
you can if that sounds as awesome to you
as it does to me you should subscribe to
follow along and see how it goes
and then these videos are very time
consuming and expensive to make
if you want to help support making more
awesome things and more videos
you can check out the patreon and in
exchange i'm giving more
behind the scenes content probably the
coolest thing is the discord server
i'm having a whole lot of fun hanging
out in there with people and getting
advice on my projects
alright that's enough of that back to
how about they sports team i mean i
don't think there really are any right
now right
the first concept that i was trying to
do involved two combs and do a
complicated series of motions
to select just the hair that i want i
even designed the mechanism to do it and
it was pretty cool the problem was
i just couldn't find a way to do this
reliably without some kind of camera to
see what's going on
but ultimately trying to figure out
where the hair is with the camera is a
nightmare of phd proportions
i think to try this would be insane i
told you that's an insane design
it's way too hard you need to pull out
the essential things that it needs to do
and then
design a way to do them that's easier
for a robot the way to go here is a
vacuum it's gonna make life a lot easier
yeah so as he's so rudely interjected i
did have some alternate ideas that
at least on paper seemed a good bit
easier since when does rude dove good
ideas you know i'm really looking
forward to seeing you stick your big
head into this robot my head no
you're the one with the bad ideas anyway
i came up with another way
of grabbing hair that uses a vacuum that
is a whole lot easier than i was going
to do before
the vacuum sucks all the hair straight
up and then if i slide two fingers in i get
get
just the hair that i want and no hair
from the sides the way the cutter head
turned out to do this is pretty cool
it only takes three servos so here's the fingers
the scissors are on a little stage
driven by a servo
and then the scissors are actuated by
another servo so putting these things
together i can move the fingers grab
some hair lift up
and then cut unfortunately this wig hair
is it's like wire
so the scissors can't cut it this is
unfortunate because i wanted to test it
on a wig but it doesn't work so
i'm going to have to be the first real
haircut this explains the sense of
do anything fun this weekend it was
really sad my dog died
the other big challenge of this
haircutting attachment is how do i move
it to all the different locations on the head
head
and so what i did is rather than having
a three axis system
i have an arm that can move in and out
and up and down only
and so it can reach the face and they
can reach the head
then i rotate the entire head so i can
reach the side
i just rotate the head now i'm touching
the side and so
rotating the head is hard because i have
to rotate my whole body
i do the equivalent thing which i rotate
the entire robot around the head
i always need to be pointing at the head
when i cut so i'm cutting on the top i
need the scissors to be pointing this
way if i'm kind of on the side maybe
pointing this way
and so i added a whole extra rotational
mechanism to the
to the robot gantry to allow this one
other problem that i ran into that
really annoyed me because it just made
things way more complicated
is that depending on where you're
cutting on the head you want the
scissors to be going different directions
directions
so when i cut the bangs i want to be
cutting across the head
i don't want to be cutting vertically if
i cut vertically i'm going to end up
with a
diagonal sawtooth bangs which is going
to make me look like a complete idiot
so i added a whole new access to my
robot that allows me to rotate the
cutter head
this machine is made with a bunch of
different techniques the first is plasma
cut and folded sheet metal you can see
the plasma cutter is drawing these
marker lines and that's so i can bend
the parts very accurately so they fit
together later
some of the plasma cut parts are spot
welded together and you can see i'm
using a little access port so that i can
reach the spot welds inside this thing
there was only one machine part and that
was because i was able to 3d print
pretty much everything this is great
because they're complicated shapes which
have been very difficult to make
everything is built on top of this giant
bearing which is what my head goes through
through
and then there's a simple two axis
gantry i need to cut a hole in a sheet
of plywood which this cnc router i just
got would be perfect for
but it's not set up so i had to make a
tool to do it using your tools to make
new tools is one of life's great
pleasures anyway so it was fun
and then everything rides in this stand
i built which bolts to my workbench
so electrically there's really not that
much interesting there's
four big stepper drivers which are
responsible for controlling different motors
motors
there's a microcontroller it's a teensy
that's running the show it's
communicating with the computer
for receiving commands and all that
stuff it is a giant mess but
there's nothing like a good facade to
give the impression that everything is okay
okay
all right how you feeling i'm a mess
i mean i am good thanks how are you
when can i cut your wife's hair it's not
gonna happen trust me i tried
all right what if i give you a haircut
that is a super set of another haircut
that you want
then if something goes wrong we can cut
your hair down to another haircut
what do you mean if something goes wrong
i mean i don't plan on anything going
wrong it's just it's a prototype and
sometimes stuff happens i already like
my hair
but come on it's important it's for
humanity humanity again
yeah there's all these people stuck at
home in quarantine and they want to look
good how does getting my haircut help
it just does that doesn't make any sense
just put your head in the robot
it's that easy you just put it in and
it'll cut it my analysis is that you've
made yourself into the man who cried wolf
wolf
even if you really mean well you're not
going to be able to convince
where did that come from oh well cool
one of the big challenges of getting
this robot to work is that it needs to
know where my head is
in order to cut the right length if my
head is here it's going to cut a
different length than if my head is here
your head moves around a good bit and
i'd rather not have every little
movement that my head does
baked into my haircut i spent way too
much time trying to get this depth
camera working
so this is an intel realsense depth
camera and what i was doing
is doing facial recognition to find
where my head is
and then combining with the depth data
to figure out where my head is
in 3d space but there was a really big
problem with this switch
this camera is completely blocked by
this stand
a lot of the time even when it's not
directly in front of it it really blocks
it and
i could maybe deal with that but it
makes the software so much more
complicated i just didn't think it was
worth it
what i ended up doing is i put a little
switch on these fingers
and this allows me to move and sense
when it hits my head
and then i can use that to measure a
bunch of different points on my head
and figure out roughly where it is so
say i get a little bit too comfortable
in here and i
kind of move over to the side it knows
because it has this probe
move back move back move back go ahead
all right we're back in business how do
you tell a robot what haircut you want
the way that i solved this problem is i
took a 3d model of a head
and i painted on it the haircut that i
want basically
lighter is longer darker shorter at
first glance this looks like i want to
be a balding man but
it actually makes sense to the robot the
other thing i have to tell the robot is
what angle to cut at because i wanted to
cut my bangs horizontally and i wanted
to cut around my ears
so this isn't telling the robot that i
want a giant unibrow this time the robot
cut the bangs horizontally and then cut
around my ear
the robot will load this 3d model and
then knowing how big of an area the
scissors cut it will compute a plan
of the minimum number of locations it
needs to cut at to make my hair
the desired length and then as it's
doing that plan it'll cut one and then
go the next one in the next one
at each location it will check the
unibrow model
to see if it should cut at a specific
angle and if so it'll do that
at least that's the plan in theory i
haven't done it yet hopefully it works but
but
we're doing it live so here's the whole
haircut from start to finish
heads up i look completely insane in
this time lapse
i think it's a weird time lapse artifact
but also i was terrified of it ruining
my hair so it's
probably also a bit of fear midway
through i realized there was a bug in my
code that made it cut about
six times as many locations on my head
as it needed to
i thought it was taking a while so it
took about an hour
but it should only take more like 15
minutes every time the robot goes to cut
a location
it probes to find where my head is at
and then the length that it cuts is
relative to where it probed this is the
main reason it could maintain accurate
hair lengths even though i was moving
around so you can see the vacuum sucking
a bunch of extra hair into the tube but
the fingers that grab the hair have
little guards on them that keep hair
that they aren't grabbing from being cut
making this robot hit the desired
location on my head was pretty hard not
only does it have a bunch of joints that
are somewhat challenging to compute
where the heck the scissors are going to go
go
my head is moving and then the design of
the robot doesn't allow it to approach
my head from all possible angles
i have to find the best achievable angle
that the robot can do
i have a suspicion my math isn't always
correct but thankfully my hair all
turned out the right length
all right the cut is done what did the
salon's first customer have to say
all right two out of ten not great zero
personality i can believe that
top and sides are cut well nice nice but
it gave me a mullet what
the robot cut the hairs that it could
reach really well
but there's two problems the first is it
can't get close enough to my ear so i
have all this
hair right by my ears that's really long
that should be pretty easy and fast to
clean up
but the big problem is it gave me a
robotically perfect mullet
so it just couldn't get quite low enough
to cut the last
maybe inch of the back of my hair i had
planned to have it rotate which
dropped it by about an inch maybe an
inch and a half but the scissors
interfere with the stand and it just
couldn't do it so i said i thought it
was gonna give me a five dollar haircut
i think that was right i think even for
five dollars they don't normally give
you a mullet
man thank goodness i didn't prank my
wife with this machine because
i had to just go give her a pair of
scissors and ask her to fix my hair
i'm actually really happy it gave me the
mullet there's just something deeply
satisfying about a robot giving me a
perfect mullet all she did was cut those
off she didn't touch the top at all
and overall i'd say it's really not bad
i checked some of the lengths they seem
right on
and i'd pay five dollars for this
haircut i don't get another shot at
cutting my hair for
a month or two but i think i might try
to upgrade this to cut closer to the ears
ears
to not generate perfect mullets and then
maybe also add a trimmer or something
like that so that it can
do the neckline for me so hopefully you
enjoyed this there's a fun project
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