hey I'm going to LA with iFixit in today
I am joined in our studio by our very
own teardown engineer Andrew thank you
for coming in today so what do we do
yesterday uh yesterday we took apart the
new 13-inch retina MacBook Pro and it
was so disappointing one quarter one it
was it was score to one yes internally
pretty much the same it scored one for
all the same reasons as the 2014 and the
2013 yeah and the biggest reason is the
the horribly glutton battery that just
makes it very nearly impossible to pull
out and replace right and very difficult
for recyclers to pull it out when
they're recycling and need to separate
the battery out before they can get
anything useful out of machine or shred
the aluminum down yeah so but there was
an upgrade that's pretty interesting and
we decided to talk about it a little
more today we've got the trackpad the
force touch trackpad and we also brought
in an older one just so we could do some
comparisons can you tell us a little bit
more about the ins and outs of radio
trackpad here so Apple first announced
the the new trackpad coming in the
12-inch MacBook but they also gave us a
sneak peek at that by including it as an
upgrade in the 13-inch retina so this is
a slightly different implementation then
the the renders showed in the upcoming
MacBook but it should operate about the
same way and while it looks pretty much
the same on the on the trackpad surface
it's pretty sure extinguisher bolt it
what's glass there they're both it's the
same size same glass surface same size
feels the same okay what it's different
is underneath so we used to have a
single micro switch right here yeah
single micro switch that would register
every click epic well the whole trackpad
bounced on these two hinges back here
right and now the trackpad doesn't have
that diving board type thing instead
it's floating on four metal Springs each
with a strain gauge that works to
measure the Flex on those metal Springs
and measure the pressure spread out
across the four posts so basically you
can click anywhere on the trackpad and
get the same feel where's right this one
you're you're mostly clicking at the
bottom there's definitely a hinge
feeling with the old trackpad and this
you can click anywhere you can click up
here or down here
here and it will measure the force that
you're applying on all four of those
posts so we'll know how hard you're
pressing pressing and where you're
pressing in how hard so Andrew you
mentioned strain gauges can you explain
that a little bit and where they are on
the truck bed
absolutely so each of these four metal
Springs is able to flex slightly as you
push down the track from above and this
tiny little component here we believe is
actually a series of strain gauges that
measure that flex and convert that into
a pressure sensing of that that
particular spring okay and a strain
gauge works off of a principle called
Poisson s ratio which is that as you
stretch a wire the diameter will
decrease and the length will increase
and that will increase the electrical
resistance of that wire so in this tiny
little sticker right here are many many
zigzags of that one wire going back and
forth in the direction of the Flex so as
it flexes down like this the wire is
lengthened in the resistance increases
as it flexes up like this the wire is
shortened and gets thicker and the
resistance decreases so there's a little
microcontroller in here measuring that
resistance for each of these four
components and then translating that
into a pressure force that was pretty
cool too when they talked about it in
the keynote talking about you know your
signature or fast-forwarding it's it's
all in the pressure and it can feel how
hard you're pressing yeah I think Apple
is definitely trying to start a new
standard for trackpad use they're sort
of sticking to their guns once and for
all for the single button model Steve
Jobs first introduced and now they're
just adding a new dimension to that
single button basically you can press
lightly or hard and you can do the force
click which is a deeper click into it
great so let's talk a little bit about
this technology that we have here now
this is the taptic engine what are these
parts
exactly here this is just a this is a
series of just four electromagnets just
electromagnet there just let them it's
very sleek we've had for a while yeah
yes in Sun in 1820 forms when yes our
engineers and scientists okay that one
and and so how do they how do they work
how does the trackpad read here so so
this little module here is what Apple's
calling the taptic engine and it's for
electromagnets with a fancy name
that line up with this ferromagnetic
steel bar okay that is attached to the
bottom of the trackpad but it's separate
so by powering or D powering these
magnets are changing the direction of
the polarity on them it can essentially
pull or tug on this little gap here
right here which will move the trackpad
up above and it can kind of flex a
little bit on the for spring posts so by
rapidly changing this it can create a
slight buzz and when you press on this
trackpad it feels and sounds exactly
like a click on an older trackpad
without actually clicking anything so
they've done a really great way to
remove what we're used to and simulate
it wow this is really really cool
so um last what do we have here this is
this is just one of those taken apart
yeah so this is just copper and it's
called motor winding wire okay and it's
a very thinly insulated wire I can pull
this piece off a little better and
that's not going back I don't think so
no so this maybe don't take that part
apart yeah this is probably not a user
repairable part but we just unwound this
to see what was underneath and this is
just a ferromagnetic core that makes the
electromagnet stronger and originally
this was wrapped all the way around it
and you can see there's quite a bit of
wire on each of these four
electromagnets yeah well needless to say
this is a very complicated trackpad
compared to jack pads in the past
definitely um and we're seeing it in the
13-inch Pro and then we should be seeing
it in the MacBook correct but it wasn't
in the heirs and the 15h pros so be
looking for those and thanks so much for
coming in yeah and explaining it a
little little further now glad we could
take a look at it all right thanks
you