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[Music]
and uh good evening to everyone who is
here at the camp um we have the next
speaker Clemens who is going to tell us
about Electronics prototyping why it is
very easy and why there's no reason you
shouldn't be doing it
yourself give a big hand to
Clement thank you everyone the heral
complained my ti was too long so it's a
bit shorter now so yeah building
Electronics is
easy um I can say this with confidence
because I I teach uh building
Electronics to people at every event and
they succeed at an overwhelmingly High
rate because it's so incredibly
easy but for some reason people see
still seem to think it's
difficult and yeah I'm giving this talk
to try and counteract that
sentiment so a few years ago someone was
wrong on the
internet and they they kept insisting
that there's no way
to to actually assemble surface mount
parts with um like basic home equipment
and uh that that was obviously wrong cuz
that's something I'd been doing for for
years and uh yeah I wasn't about to let
that slide so in in
2015 um I I put together this uh this
this small board design and I had no
idea what I was doing but uh I set up a
workshop teaching people that was at
maker Fair R and it was a complete
disaster cuz I had no idea how to teach
but uh surprisingly every single board
worked at the
end including the one that was assembled
by a blind
person yeah who had his daughter sitting
next to him going a bit to the left a
bit to the right and that board worked
every single board worked and a comment
I got at the end of the workshop was I
kept waiting for the hard part to come
and it
didn't so yeah that that kind of got me
on this and uh yeah I've been doing um a
workshop on Surface m assembly at every
event I've been to ever
since um and yeah um the situation now
is that building Electronics has never
been easier than it is now because every
part of this pipeline is extremely
accessible now so getting your own pcbs
made uh just a couple decades
back uh this was
effectively like you know had to have a
home chemistry lab or you had to have
know somebody with a CNC or you have to
have a [ __ ] on of money and that is no
longer true because you can get the
circuit boards made extremely cheaply
extremely quickly and with uh very high
precision and there's now free software
tools that you can use for Designing
pcbs and there's two of them right there
Kad and Horizon uh people who develop
those are at Camp so you can hang out
with them and complain about things that
don't work which is also awesome and one
thing that's changed in the past few
years is there's now an enormous number
of open Hardware designs that you can
look at and learn from and remix
from and yeah the only thing that leaves
is assembling your boards and assembly
is easy but people are scared of it and
they're scared of it because of surface
mount parts and most modern parts are
surface mount a lot of parts are only
available in surface mount this is this
is one of my designs
um yeah every single part on this is
surface
mount and they're actually easier to
assemble because you don't have to
solder each part
individually and the reason that most
parts are now surface mount is that it
has lots and lots of advantages for
production um so parts are obviously
smaller you can place them in a much
more automated way so for for assembling
thousands and thousands of things that's
that's what you want to be
using and you can have denser designs
you can have the parts closer together
uh they're cheaper to manufacture
because there's much fewer processes
involved in packaging a surface mount
part than a trall part um they actually
work better so their the connections uh
that um that end up there in production
are more
reliable and um yeah if you get into
more advanced applications like high
power or high speed
or um yeah any kind of high performance
parts then surface mount parts work
better because you have better signal
integrity and they transfer heat to the
board better and it's much easier to get
power into them so and this is why many
modern parts are only available in
surface mount which scares a lot of
people
away
um yeah people are scared of this
because they think they can't handle
them but uh the thing is machines can
handle them and machines are dumb
machines have no idea what they're doing
so automated
assembly um it's a process where you
program a machine and it does its thing
and it keeps doing its thing and has no
idea that it's messed up until the end
of the process and at that point you can
have an automated process that detects
errors but uh there's no way you can
correct those errors on the same machine
so boards that come out of a pick and
place with with mistakes in them they
then get either thrown away or handed
over to somebody to fix them by hand
so the processes involved in machine
assembly have to have so much tolerance
for
error that that doesn't um make the
whole point of machine assembly go away
and they are and those tolerances that
tolerance for error means it's extremely
easy for us to assemble them by
hand so with surface mount we can cheat
and we can cheat in three ways we have
stencils we have Reflow and we have
precise
placement so stencils are a um sheet of
metal with holes in it where the
contacts on
the um on the parts are meant to go and
they let us apply solder paste in tiny
bits in precise
shapes and um we can make those way way
way small than anything we we would want
to handle by hand so you can see on the
on the right there's this uh rectangular
chip which has uh 32 little pads around
it and every single one of them is a
single blob of Soder but the only thing
that we needed to do to get that blob
those 32 Blobs of Soder on there was
scrape over the board ones like shown in
the picture on the left and
um yeah the the material used here is
solder
paste which is basically the same as
solder wire except it's cut into tiny
tiny little balls and they're swimming
in
flux and what this does is it allows us
again to make um to dose it much more
precisely so we can we can have much
small bits than if we were using solder
wire and the process that this enabl is
Reflow so we can solder all the things
at the same time rather than
individually and instead of having to
very
precisely um uh make each solder joint
we can use the properties of the
material the properties of the soldar
paste um so the soldar paste likes to
form individual blobs that are separate
from each other because of the flux
that's in it so when the solder paste
melts all the little balls melt together
and they form individual blobs that
individually make connections between
pins even when they're really close
together and this is what enables the
density of dense surface mount
parts and the last way that we can cheat
is precision placement because uh none
of the parts are actually soldered on
until we heat up the whole board so we
have many hours in which we can adjust
the position and fix mistakes before we
actually heat anything
up yeah this is the bit that actually
scares the most people the actually
placing things on a board and this is
because people are afraid of their hands
shaking yeah um human hands do not shake
this is not a
thing if you've experienced your hand
shaking your hands do not Shake it's not
your hands it's something else uh so if
you were to try and like hold your hand
precisely a certain height above the
table you'd notice that it shakes and
the reason it shakes is because of the
delay in your visual processing system
going from your eyes through your brain
to your motor control system and that
Loop is very very long because the brain
is really slow at processing visual
information so uh if I notice my hand is
too high I want it to be lower by the
time I've gotten it to the point where
it's lower it's gone too far and then it
needs to go back up
again and uh By the time I've done that
it needs to go back down again and that
delay between perception and reaction is
what makes the hand
shake and there is a Technique we can
use to switch that
off so instead of using vision we can
use our sense of touch which is instant
because it doesn't go through this whole
visual processing system so if you try
and hold out your hands in front of you
like
this and almost but not quite touch your
fingertips you'll see that they
shake and then if you then bring them in
a tiny bit closer so that just one pair
of fingertips touches that pair of
fingertips is no longer shaking that
point where they touch is solid
everything else is shaking way more but
that point where they touch is solid
because your finger then knows it needs
to stop moving when it senses touch and
the sense of touch is instant and by
using this technique we can then
stabilize things and place them with
extreme Precision so this is the
technique I I teach in my
workshops which
is using that sense of touch using the
second hand to to touch the fingertips
of the first hand and that stabilizes
the tips and uh stabilizes the entire
system and with this you can place
things with unbelievable Precision
better than any pick and place
machine yeah um so that's basically all
the things you need to to assemble
Electronics is yeah uh the correct
technique some very minimal tools and
and way to heat things up so this this
is a minimal Reflow setup there's
there's very
little happening
there so this is just a normal boring
Hot
Plate entirely like standard there it's
not doesn't have any temperature control
it doesn't have any like process control
like doesn't follow a temperature curve
or anything else I I just put s on there
and hit them up
and they
work yeah and you can use this to
assemble extremely Advanced boards like
this this thing here is
a eight eight Port input four port
output uh uh HDMI Matrix switch which
runs at uh 6 GHz per
Lane and yeah it was built by this exact
me method and it works
fine so there's there's no reason this
is this needs to be limited to hobby
electronics so this this is all you need
for a minimum Reflow setup you need a
hot plate you need solder paste you need
tweezers you need flux you only need the
flux to actually fix things afterwards
cuz there's already flux in the solder
paste yeah uh thermometer some really
good
light and yeah then your consumer was
your boards are stand still s Your
Parts yeah that's that's really it
there's there's no more and you can do
it many many many people have
successfully done this in my presence
with no prior experience in the middle
of a field in exciting
weather uh not so much at this event but
at some previous events like we had
Parts flying around in storms and things
like that it worked out every single
board work so you have no excuses
yeah that's it uh I put some details
about the things that I use on this
slide so I'll leave this on and yeah if
you have any questions now would be the
time yeah thank you round of applause
for
Clement and we have an angel over there
with microphone so if you have any
questions
about about how to yeah there's a
question over there on your on your
right first thank you for the talk
uh one question would be sorry uh one
question would be uh I have kind of a
bit of a problem with uh inspecting
stuff in the case of bjas because you
can't really see behind the first row
yeah uh do you have any like of tip for
that okay so BGA are actually some of
the easiest parts to assemble
because there's so many individual
solder contacts that the parts self
align really really well so with BGA in
particular the most important thing is
actually get the paste print really
really good and it will work out uh when
you're placing it you want to not squish
it
down uh because if you do then it's
impossible to inspect them but usually
if your first two rolls are good then
the rest of it will be fine as well is
there hello is there a way at home to do
uh Parts on both sides uh there is so
you can you can Reflow one side uh first
with all the small components and then
Reflow the second Side by propping it up
on
something um yeah that's basically how
it's done in Industry as well if you
need something more advanced than that
like if you have large Parts on both
sides
um it makes sense to glue them down so
if if you have like large connectors one
thing I've done sometimes like for
example with this um with this board uh
there's some connectors on the bottom
side and Uh I refloat that side
first and then I used high temperature
solder to solder the mechanical pins in
place and then you can refl the whole
thing and they won't fall off but if
you're doing double-sided stuff it makes
sense to use an oven for that I don't
like using an oven for prototyping
generally because uh you can't reach
into an oven and make changes to things
which you can on a hot
plate but uh yeah if you're doing lots
of double-sided stuff that's that's
where it makes sense to do it in an
oven okay any further
questions there's so I had a question
for you which is um you've talking about
reflowing with the solder paste and
stencil what about skipping the stencil
in the paste and just soldering by hand
with a similar technique and
individually soldering do you find any
use for that still yeah I mean of course
you can do that it's just there's no
advantage to surface mount if you do
that okay we have a couple more minutes
so if you can think of any question now
is your chance to do that um out on the
interwebs there is no question yet no
um I'll count to three in my head while
I'm waiting for another
question there does not seem to be
anyone who dares to ask questions
anymore so oh there is someone coming
up hi so when I'm prototyping things I
still use lead solder because it makes
everything better and wonderful for
people who are prototyping
today is that a good idea is that a bad
idea okay so I for hand soldering I use
uh solder with germanium in it which is
as good as lead
solder uh but way less
toxic um yeah for for reflowing I I
usually use bismut based sld because
that reflows at a much lower temperature
and it has an enormous process window so
any temperature between 140 and 250 is
fine uh so you you don't need to worry
about getting the temperature
right uh so I haven't done this myself
yet but um in terms of ordering boards
and stencils do you order them from
separate vendors or do you order them
from the same one do you have a vendor
that you enjoy working with a lot for
this so I I don't like the name
vendors but uh yeah always get the
stencil from the same place as you get
the board uh it saves you own shipping
and it makes sure that they're aligned
uh one thing you can do is um let me see
if I got a good photo of
this so over here uh We've aligned the
board with the stencil using two screws
only one of them is visible over there
uh so you can do that uh to to make it
easier to actually uh align them to each
other okay and um this leaves us with no
time for further questions so um thanks
a lot for joining us here this evening
and another big hand of Applause for
Clement for his
presentation thank
[Music]
you