hey robot fans in this video I'm going
to show the head mechanism for my bb-8
build a lot of questions that keep
coming up on the forum and the facebook
group are how can I get the head as
light as possible how can I have enough
magnetic pull to keep the head on and
how can I keep the motion of the head as
smooth as possible a lot of builders
have come up with some great solutions
this is my solution as you can see the
head move side to side and front to back
really well even as it drives it moves
very smoothly I was also able to get the
lights and sounds into the head all for
the low low price of two pounds and 14
ounces so in this video I'm going to
deconstruct the head piece by piece show
you all the parts that I created and all
the parts i modified i'll also provide
the STL's and a material list so you
could recreate this head mechanism if
you'd like so let's get started with
that let's start with the parts that I
didn't modify at all the radar I the PSI
and the hollow lens or exactly as they
were in the club files the antenna that
i'm using actually came from another
builder Matt Hobbs did a run of flexible
antenna these are great they're super
high detail really light and they take a
bit of a beating for when your dome hits
the floor the first piece that I
modified was the top of the dome this
used to be two pieces the pie panels and
the dome top I combined those two
hollowed out the inside and split it
down the middle so it could print side
by side on the print bed these can be
printed with no supports and the
lightest infill possible I also added
in a rim so that when you attach it back
to the dome it attaches with a push fit
rather than the magnets this gives it a
little bit of side to side
stability it takes a bit of a beating
you can turn it upside down doesn't
budge the next main parts that were
modified where the dome and the skirt
ring combo I think these can be shown
better in 3d studio max so let's take a
look at that ok the dome on the outside
is relatively untouched I did most of my
changes to the inside structure when I
downloaded these files it was January of
2016 that's when I started building bb-8
and I was having trouble with my drop
box so i just downloaded all of those
club files to my local server and have
been using those i know the club has
made a lot of modifications to all of
the files but this is based off of the
original january 2016 batch i deleted
the inner rim here
they used to have holes to attach to the
top of the dome ring I think it's pretty
widely accepted now that the dome spins
above the ring so those are unnecessary
I left a small brim so it can glide
above the dome ring I also added in this
cross brace this brace is what attaches
to the main mechanism and also gives you
a lot of mounting room for electronics
and batteries the next piece is the
skirt ring combination again in 2016 the
skirt and the ring or two separate
pieces and they did not have any of
these vertical notches which are seen on
the movie droid so what I did basically
was just attach the two pieces together
and hollow them out the original ones were
pretty chunky I can actually show you
those in real life I hollowed it out
added in the notches if we look at a
section of this piece you can see it's
relatively Hollow it just has enough
enough thickness to support it and I
really wanted to make sure that my
intern internal wheels cleared this
bottom ring which they do so here's the
whole piece o actually this is half of
it but this can print in one piece
upside down with no supports i had no
trouble printing it with no support the
dome however does need to be printed
with support just because of this cross
brace so if you have simplified 3d or
another slicer or you can modify the
supports the only place you need to put
supports is underneath this cross brace
so like I mentioned earlier this was the
original skirt ring combo it had this
wider brim with the holes in it and the
skirt was pretty chunky and I just
hollowed that out and printed it light
this came in at about 12 ounces i think
it was 11 and 7 8 and this is about five
and a quarter ounces so the white
difference is pretty significant and all
we really did was just remove a lot of
this mass that isn't necessary and only
got in the way of the wheels sticking
with the ring skirt piece we could start
to talk about the main head mechanism
this is an old test ring but here you
could see the main assembly that
attaches to the dome ring which will
allow the dome to spin freely on top
while this remains stationary it
consists of three legs and a central hub
that contains a six millimeter bearing
construction for this is very simple the
legs print out like this push fit into
the hub and
and that is a BF solve and welded
together at this point you're going to
want to insert your caster wheels the
casters are based on the James Bruton
version 3 caster wheel I just made them
a little bit smaller and a little bit
lighter here's one of my old Bruton
style casters the wheel is about ninety
percent of size and it's printed in
white semi flex it's important to use
white because the black or any other
color will leave scuff marks on your
droid I learned that one the hard way
also i was using steel in the Bruton
version four millimeter steel studying I
found a big problem with this was that
the magnets attracted the axle and would
get stuck on it and then cause the wheel
not to rotate properly so i switched
those out for three millimeter brass so
the construction here is simple it's the
semi flex tire to abs hubs and then the
main central caster hub and a brass axle
that goes through and there's two
additional three millimeters shoulder
washers inside there at the top this
brass gets inserted into the bottom of
each of the arms which also has a
shoulder washer here it slips in today
like that and then I printed out these
little end caps which are glued onto the
top of there and when that's glued this
will hold it in place enough for when
you pick up your head that it doesn't
fall off with author casters attached
you can place it on the body nice smooth
movement the as their wheels rotate they
eliminate any jump or skip next up will
be adding in the magnetic mount and let
the body control the movement of the
head this is my body magnetic mount
which I'm affectionately calling the
bear claw it uses the same magnets
recommended by the club for their setup
it has the two-inch disc magnet and the
one-inch disc magnet I actually used an
extra one in addition to what the club
recommended because I was very concerned
about having enough toll for the head
however when I put this in the body and
I made the match for the head I found
that this many magnets was too much pull
so I had to reduce it quite a bit i
reduced it down to this which just used
the two-inch magnet and the center to
one inch magnets this has been perfect
and I even have this quite a bit away
from the top of the droid and it's
holding really well I think I can
explain the construction
this a little bit better in 3d studio
max so let's take a look there here you
can see the dome magnetic mount paired
with the bear claw inside the body this
ring right here represents to James
Bruton cheese and the body panels as you
can see the 1-inch magnets are closer to
the body panels than the two-inch magnet
this is the distance that's needed
between the two inch magnets to have
them wheels spin freely and have the
head moves very smoothly anything closer
and the magnetic force is way too much
however at this distance the 1-inch
magnets are pretty useless so I bumped
them down a little bit just so that they
would properly pair with the body and at
this point they're basically just being
used to orient the dome magnetic mount
to the bear claw and the two-inch magnet
is doing the bulk of the magnetic
pairing this is the way the dome
magnetic mount looks when it comes off
the print bed there's two risers for the
1-inch magnets of recess for the 2-inch
magnet and another recess for a nut in a
screw that screw is basically just an m6
bolt with a nut attached to it the nut
is screwed all the way to the top and
that's what's going to be used to anchor
it into the dome magnetic mount if we
take a look at that part again we have a
the screw goes into that recess then the
magnets come on top and the magnets are
screwed into place with a 1 inch 1024
bolt
on the top you can see that there's a
1024 nuts securing each of the magnets
and there is another m6 nut placed on
the back of the dome magnetic mount and
there is a washer placed over that this
washer is what will make contact with
the bearing in the spindle and help it
spin freely using these washers you can
really dial in the distance between the
body panels in the magnetic mount by
adding more washers you could bring the
magnets closer to the body panels and
have a stronger magnetic pull on my set
up there are two washers in between the
nut and the bearing and that seems to
work really well for my setup when you
figure out the proper number of washers
you insert the entire assembly through
the bearing of the spindle then to
secure there's an additional 3d printed
spacer which has an m6 lock nut embedded
inside of it this spacer spins all the
way down the m6 bolt until it's touching
the top of the bearing in the spindle ok
that gets us to this point where we have
a free spinning magnet assembly next we
want to add the last piece which will
attach to the dome but before I do that
I just want to mention the felt tape
that I have on the top of the ring this
will help eliminate that annoying
plastic scraping sound you hear the
first time you rotate your dome I in
said it a little bit off of the edge so
that it wouldn't be visible with the
dome on top it's also important to sand
down the bottom brim of the dome with
the highest grit sandpaper you could
find I also added a couple coats of
lacquer on it just to get it as hard and
smooth as possible so it glides really
nicely along that felt the last piece is
this cradle piece which attaches to the
dome crossbar it screws into the top of
the spacer using a half inch number for
wood screw so if I attach that ok you
can get a good idea of how it's going to
rotate here let's take a look at it on
the droid to place it on the dome just
hover it above and the magnets will
orient themselves and place it down now
you can see the rotation and you kind of
get an idea of how that cradle is going
to move the head when it comes to
placing the dome I have an arrow put
onto the cradle that points to the front
of the dome just for consistency sake
and from there it's just the push fit
the cradle will hug the crossbow
our and that in addition to holding the
dome secure will also give you a little
bit of tolerance in the overall dome
height which is important so if you look
here my dome is a little bit on the
loser side so when I turn it it kicks
back so this isn't something that I
necessarily want so i can push down and
give a little bit more tension on the
cradle which will give a little bit more
friction on the felt tape and then you
get some smoother dome movement and if
that ends up being too much you can dial
it back you can really tighten in the
head to whatever kind of strength you
want with regard to how it stops or how
smoothly it moves around ok lastly I
just want to give you a quick overview
of my electronics setup inside the dome
I have these two 3.7 volt lipos wired in
series going into the disco droid module
from Jim Harvey you I also have the HC e
05 bluetooth module talking to the disco
droid for my remote control and the
outputs from the disco droid are a
neopixel strip which lights all the
logic lights and the hollow lens and led
a single white LED going to the PSI and
six red LEDs going to the radar I the
sound comes from a TT 25 transducer
which is really loud and really awesome
so let's take a look at all of this in
the actual dome ok looking one from the
top of the droid you can see I have the
disco module mounted to the main cross
bar right next to the hole there with
two screws I have the HD or/5 bluetooth
module glued to the top of the disco
droid unit if we flip this over you can
see I have the TT 25 transducer hot
glued to the side wall just opposite the
hololens area the figure that was the
best place to counter the weight you
could follow my Neil pixel string here
it goes to the side blue logic here I
have everything covered with the same
felt tape just to eliminate any light
bleed then it goes over to the two side
logics there next up i actually have a
backup PSI sitting in here attached to
the neil pixels i couldn't get the
coating to work with the sound right
away so i ended up putting it another
with a standard LED but hopefully I'll
be able to eliminate that whole string
and just put this back inside there and
then the neopixel terminate at the
hololens coming out of the radar I I
have six red LEDs which i'll be using
for animation and then the last thing i
want to show you is my battery setup so
here's my battery setup I have those
same two little lipos into this bracket
that I made then you have a series
wiring harness on the back here which
goes to a power switch this wire then
would go into the disco droid unit and
this whole thing push fits onto the
crossbar to pretty snug fit this thing
has fallen off a couple times and this
thing hasn't gone anywhere and that's
pretty much it this video has been
pretty specific to my particular setup
but this should work for any magnetic
setup so long as you can attach it to an
m6 bolt you might have to adjust the
size of the spacers or add more or less
washers but it should work thanks for
watching sorry got so long-winded but if
you made it this far maybe consider
subscribing to the channel for more vba
videos and my upcoming chopper project
there are links to all the products in
this video in the description as well as
links to my social media page so check
them out and I'll see you next time
Oh