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Yeah, my name is Sarah.
I come from the region here I live in the
region of Kalsu.
I work with lasers in my
in my work and I develop things like
this. This is an industrial laser system
for marking pieces of metal,
pieces of plastic in a in a line
where products go through.
In my free time, as you mentioned, I'm
in the fab lab where we
developed or build
the laser sound, which is an open source
project. And
so I have two laser sites, one network
and one one in my free time.
And so
I did an experiment with the CO2
laser in the fab lab.
I wanted to know what happens
when the beam goes on the skin
and the result.
So I went to a butcher and
bought a piece of pigskins,
five, six millimeter thick,
and I put it on the laser and switched
on the fume extraction and said,
OK, don't know where to start.
And
this I come to later.
So and I ended up with this
on the top,
you see 10 percent input
power at
a thousand millimeters minutes
writing speed.
Second line on the on the top left
is 50 percent of
power and the third is 100 percent.
When you look closely, you can see
that the the O's and
zeros that
meet the skin was lays
it out and fell down.
So then I was scared.
I was really scared.
It smelled like hell.
I was close to vomiting.
And I thought, Wolf, I
didn't expect this.
And the second on the left
hand side, three rows
where with 8000 mm.
Minute marking speed.
I don't want to have this
on my skin or in my eyes,
definitely not this
I can't describe, I can't imagine the
pain and the consequences
of medical consequences.
So therefore,
you are responsible for
what you do with lasers.
You everyone is personally responsible
to wear the safety goggles,
to take care that no beam goes
goes out of the compartment.
So whenever you hurt yourself, don't
take me reliable for it.
Oh, Sarah didn't warn me about this
matter. No, absolutely not.
You are responsible.
So read the standards,
read more, read some other
literature.
Think about what you're going to do
seriously. Think about what you're going
to do. It is so dangerous or
can be dangerous.
And yeah, obviously,
before you switch on the laser system,
please switch on your brain.
This is vital.
This is really important.
So
by the way, this was done with a CO2
laser at ten thousand six hundred
nanometers and
I don't know the output, the optical
output power, but the input power was
maximum 100 watt.
So I
guess 60, 70 watt
output power, optical.
Not nice.
I came across some
preparation to this talk, I came across
some some nice pictures
and some nice stories I want to share,
especially what is very vulnerable
is the eyes, obviously
skin you can repair.
You go to to to the to the hospital
emergency room and you get fixed up
with your eyes. It's more difficult,
especially in the visible range
of light.
The top left image,
there was a guy who had to set up
at home at
one vitalism, a blue laser
system, and it
was standing on a chair
and he wanted he did
something.
I read the story was very vague,
but he wanted to switch it off.
So he got off his chair where he was
sitting to to tinker with the system
and he stumbled
upon a cable.
And the whole laser set up
from from the other tower fell over.
And somehow he got him.
He got the beam for his eye.
This is one year
after the accident.
And I mean, imagine
you have this huge spot
where you see nothing.
I mean, the the brain can
can adapt.
But I mean, such
a black spot on
one eye, you can't ignore this,
you look someone in the face and you see
black spots, you look on the traffic
lights, you see black spot.
So this was a very, very bad
mishap on the
right, the right image is
less energy
with the near infrared laser.
This is a typical Yayuk laser.
A thousand sixty four nanometers.
That's a wavelength I work with at work.
That was a short,
short pulse.
And this is something you might
recover from.
Not that the retina recovers,
but that your brain adapts
to. Oh, I
like you to take away this.
I ignore this spot.
I interpolate the image.
I did the laser talk
in autumn in in Darmstadt
at the city and
I haven't had the CO2
laser at that time.
I just had my laser from work.
So I did the same experiment
I took. I got from a butcher this piece
of pigskin
placed in the focus area and
said, OK, 20 at full throttle.
Let's see what happens.
And after one minute of marking
a rectangle on the skin,
I saw nothing.
So well, I mean, I put
my power meter, so 20 months.
So everything was right.
Then I took my my thermal imaging camera.
And so, Wolf, this is
getting hot
on the left.
You see, on the on the left image,
the range goes to 57 degrees.
You don't see anything, but it goes into
the tissue and heats up from the inside.
This must be very painful.
I don't want to to do it.
Sometimes I'm tempted to
go through the beam, but I'm not going
to do it just to to see this and
to have a sensation
on the right hand side on the on the
bottom, this big
red this glowing blob was
two, three minutes after marking
this what you see on the left hand side
and maybe you can read it.
What I've what I've written below.
This is Hollowell.
HelloWallet,
you see nothing on the skin, but
you can see it in the in the thermal
image.
I find this very impressive
and shows even
with lower with
lower energy, you can
do a lot of damage. And this gives
at that wavelength.
This gives a lot of damage inside
the tissue.
Imagine you have you have your magnifying
glass in summer and you
you you have the sun in the focus
and you have your skin starts
burning. And this is only minimum
light power.
You have whatever.
How big the magnifiers.
I don't know, give it a shot.
It's very easy, it's very easy,
you take you take a pot,
pour in some water, put it on the oven,
on the cook and the cooker,
heat it up and hold in your hand and
a thermometer and see when when
the pain starts to become unbearable.
So 60 degrees.
So the question was at which temperature?
Yeah.
Anyway, so this is painful.
I don't want to do it.
I want to show you no
harm.
I talked about the
danger of the optical radiation
we have we have two more two more
dangerous sources of danger.
One is when you
handle a gas laser
like a CO2 tube or
different different gas mixtures,
you need to have a high voltage.
The laser at the lab
wants to have 5000 volts
and we give them 30 millions.
This is deadly.
Simple. This is deadly, you touch it, you
die mostly.
The other thing is
what happens when you
apply a lot of energy, thermal
energy, onto whatever material
it evaporate.
And sometimes
the molecules, the burning
of the molecules break.
And then you have quite some funny
things.
I made a video with the with my laser
at work.
This is thousand sixty four nanometers
on a special cardboard, which is
painted with a lack to
to see if the geometry
is right, if the policies are right and
so on.
But what you see as well, I switched
off the the fume extraction system, which
you can see at the right hand side, the
hose,
the smoke.
That's coming up.
This smells bad.
And when you do,
let's say, five to ten markings
on this cardboard, you feel a bad
feeling in your tummy.
Now,
imagine you have some other materials.
You have plastics, which is
a mixture of different different
elements and molecules, and they break
up and suddenly you have
some some delicious things like
cyanide, foreigns, dioxin,
chlorine, formaldehyde.
Not funny.
So I don't want to smell this.
I don't want to have this in my system.
Azfar When you do do metal marking,
you need to have a fume extraction
when when you mark on stainless
steel for example.
So it's not just iron, it's
other metals as well, and
it's in a lot of different metals.
So it splits into
the elements like nickel, chromium,
Mongan, cobalt, niobium,
beryllium, LED's and so
and when you take ceramics you have the
same yummy delicious contant.
A fume extraction system is very,
very important, very vital.
If you do something in the
in the region of material
marking when you want to change the
material. So if you just have a laser
pointer and you change your cat.
So this this doesn't apply.
This is only if you do something with the
material.
So this mentioned standard
end 150,
11, five fafi.
This is our come to standards later.
This is a first introduction
into the standard.
A lot of things around lasers are
standardized
wavelength to
to energy and which
class it gives and so on,
I think
protective material has to be how the
the glasses have to be
to be made, of which
answer quite a lot.
I would come to this later.
I'm going to talk about laser classes
now.
Shut down.
Not yet.
Some funny things you shouldn't do
on the top left side, top
left image. This was last year in the
hack center.
I want to apologize to the to the
taxpayers, to the Stuttgart hackers,
because we projected some some
images at the wall
above them. And I was a bit
too old.
Is it OK?
OK, so
I'm sorry for that.
What do you see as a 400, 500
million light blue laser
standing on the on the MTC DVD
box
on a on a bestrode table which
was standing on the normal table.
So it was about this height and
then we had to power supply and
then we had to galvanometer control
and so we could deflect
the beam.
So if someone pushes it just
a bit and everything gets misalliance
and someone walks by or doesn't realize
it has a blue license.
So remember, the first first
images of the eyes gives a nice black
spot.
The image below I found in a book
playing with lasers
that was in the library and collecting my
materials. And I came across this image
as no way.
The subtitle was
Please Don't Look on two reflecting
materials.
In a book you could buy
officially for the move
to tinker with lasers,
and this is one of the most stupid ideas
and I will tell you later why this is one
of the most stupid idea it has to do with
laser classes
and what you see on on the
other side, on the right hand side.
I want to go to vacations.
Excuse me.
I wanted to go to vacations.
And I had quite a lot of work to do,
programing FPGA on my laser
system. So this is the Internet of
Malaysia system and this is at home
because I'm a profaned profit,
professional, trained laser person.
I thought, well, I have my safety
goggles. I try to cut away,
close the window blinds,
and I did my programing work.
And every now and then I had to switch on
the laser and to see if everything goes
well.
So.
The lies ahead, this is a gray box
on top
there, the laser beam goes in
there to governor meters with mirrors,
and then it goes through a lens onto
the material things where the
magic happens.
And this this
brown thingy is a loudspeaker.
And what's round it round
is a five hour reinforced
tape
on the on the right hand side you see in
oscilloscope, I do not say which brand,
but it's crap.
Now, it makes it fun and
what you see in front
is the big box there
that happens, magic, electricity
and light out and
the rest is controlled electronics.
So I had to to do some work at
home. And
if you don't know what you're doing, so
don't do it, please.
If you know exactly what you do, maybe
you can do it.
Talk to other guys and maybe
you better stay alone in that
room,
not to to harm anyone
else.
Um.
Right are classes,
basically, they are
less leisure classes, which are
interesting for you.
We have Felice's classes, you can see,
but for you as hackers,
I think there are two Thalia's
of classes. Interesting.
One is laser class one.
I don't know what the old school
audio CD players have us as
a class, but laser class one is
you take your laser pointer and stare
into it. And when you're bored after half
an hour, you're switched off and nothing
happens.
This laser class one is interesting for
four high powered lasers as well.
I come to it later.
Class two
is what you have,
what you see here,
what you try the laser, you try to
cut
it.
It comes with something
that we call the ILIT reflect
eyelid closing reflex.
So the theory is that
when you get hit by this class
two laser beam, you I
will close fast enough
to avoid any damage.
And that's a weak point
of this theory.
That was a big examination,
a big test that had thousands
have 100 pupils and
they were sitting on it on a chair and
the face was monitored with a high speed
camera. And there was a line, a laser
light and coming down.
And they measured the time between
laser hitting the eye, coming
onto the retina so you could see the
laser beam.
And to look
away, you close your eyes, whatever.
And only 20 percent
of the people
close their eyes within these 250
milliseconds, which they're
the eye.
The closing reflects talks about.
So 80 percent don't be
are not in time.
So there were people even
who needed one second to realize,
oh, laser beam closing light
or looking away.
And in that time there can be some
damage.
So even this
crap here, this
pointer is not safe
for the eye, even if you can buy it
everywhere in Photoshop or
at a supermarket whatsoever.
Be careful then
we have a
class for you.
So there is a difference that
the class is one and to the
have the Mazwai and one
is you can stand to it with
a magnifying glass and
everything's safe.
And the other one is you can't use
any optical instruments.
To be safe in that class,
um,
class three is,
yeah, it's a bit less dangerous
than class for it is
there talk about
five times more energetic than
than class two.
What's really funny is class for
everything from 500 million amps to
megawatt gigawatt.
So this is
you this is a class you you shouldn't
have opened like
it did on my desk,
but you can make it safe.
You can have this gigantic
house fire, which you have in a fusion
reactor as a class one
laser. You just encapsulated
that. Make sure that no laser beam goes
out. Then you have a laser class one
system.
So the
class is as well.
This is according to the wavelength
there we have the vision, the visible
system of the visible wavelength.
And you can see it goes up
on the right hand side of where
you can see that you have a higher
region, which is have within this
laser class. This is region of the ISAF
region, which is about a thousand
five hundred thousand eight hundred
nanometers, something I forgot the number
now.
We have also a different
different damages
on the skin in the eye, according
to the wavelengths, you've
you know, you are the sun for
too long. Are you you you like
your your tanning studio too much.
You get burns on on your skin.
And when you have a UV lamps, you have
your glasses, your goggles.
So you have different types of comic
photochemical reactions of reactions
of the skin, especially with
the eyes of the UVA.
You have damage of the cornea
and the longer the wavelength
than you have in your movie, you have
the damage of the lens
and then you have a damage of the retina.
And the longer the wavelength goes,
it goes back to to to
damaging the cornea.
So when the cornea is damaged, it's
stupid, it's bad.
But you can you might fix
might be able to fix it or a doctor might
or you can have a new lens.
But this is nothing you want to have
seriously.
So standards
are very important.
You can do at home, you can do whatever
you want by you have 50
watts 100 watt CO2 tube at
the Chinese vape shop.
They are cheap.
You lock your doors, you do what you
want.
If no one else is in the room,
as soon as other people are involved, you
should read the standards
which say.
For example, the
the end 60 825,
a
number one, part one has
the safety things about about a laser
system.
You have to have a proper housing.
You have to to to monitor
any any openings.
And when when you open something, the
beam has to be interrupted.
And so and you need to have from class
laser class thie, you need to have a key
switch for access control or magnetic
card or whatever RFID
system and the lab you want to
to set up an RFID system
for the dangerous machines.
So this would would
satisfy this standard.
I could talk one week about these
standards.
They're very complex, they're very
worth to read.
You can you can read them.
You can't, as far as I know, you can't
copy them at the universities, which
have a technical department.
So as you go there, you you ask for the
standards. You ask in Germany, you ask
for any whatsoever.
And the British, you ask for a B
as any whatsoever and
you can read them.
And some.
Well,
it makes no sense to go through the
standards.
We can talk about it later on the accent,
if you like.
If you design a system,
there are some things you should
you should look at.
He should monitor every opening,
every door.
He should have an emergency system.
It is a must have seriously.
And you need to decide if you
want to have an emergency shutoff or
emergency stop that
different ideas behind
it. You need to have a shutter which
interrupts a beam.
You need to have some
excess control.
You need very important, as we saw
before, you need to have a few extraction
system you don't want to have in your
space or the chromium and
burnt wood smell.
I mean, if we before we
had a filter system in the lab, when
we cut wood, you
could smell it hundreds of meters away,
half a kilometer you could smell, oh, in
the lab they are burning what
you need to do a risk analysis.
What happens if something goes wrong?
What happens if the laser
source doesn't respond on, please
shut off and
this and that. It's a long
process of thinking.
It has to be taken seriously.
There is literature. You should take it
seriously.
You should document your project.
And unfortunately, there is someone
who has to sign for
what you do, who is reliable,
liable for this,
finally, who can
operate, I think,
on hackerspace, who is allowed to operate
the laser.
So we will have a few
short minutes.
You will find me if you want to have
some.
Some if you have some questions,
if it can help you with your laser
design. I'm here.
I'm at the center
at the fire overflow.
It's you come in the center very far
at the right furthermost
corner.
If you have questions, then
we can discuss your your issues
with lasers.
No problem. I'm delighted to do so.
Otherwise, please wear safety goggles.
And if you have any
questions, we have how many
minutes we are done.
I'm sorry.
Accent Thank you very much.