Building an artificial sun that looks unbelievably realistic…

Daylight – there's nothing quite like the
rising sun to get you ready for your day. When it enters your home it can transform
a dingy room into a vibrant and relaxing space. The warmth of the sun itself in combination
with the fresh blue tones of the sky bring a vivid and lively feel to the light making
it utterly unique and something to be treasured. However despite appearances this is not actually
early morning sunlight – to tell you the truth it is actually night time and this is an artificial
sun and in this video I'm going to be showing you exactly how to build one.

Everything you see here from the accurate
parallel shadows to the natural blue sky scattering and even an apparent space of infinite depth
behind the window is all down to a unique design that can even be made out of recycled
parts. This is gonna be a good one! This video is sponsored by Kiwi CO – more about them
later. Making a convincing artificial sun does present
a few challenges the first of which is throwing the light source back so that it appears to
be at infinity. You see as the Sun is so far away when its
light rays reach Earth they are practically parallel which is one of the reasons for the
suns unique illumination characteristics like shadows that don't change in size.

Interestingly,
recreating these parallel rays with a local light source isn't particularly difficult
as we can just use a lens you see when the lens is placed in front of the light at the
lens's focal length it actually collimates the light rays which means it makes them parallel
these newly collimated rays now have some of the characteristics of the sun namely that
the light intensity doesn't change because of distance alone and shadows don't change
in size either which is super interesting to see.

Another fascinating result is that anything
at the lens's focal point appears to be pinned at infinity and appears the same size in a
matter with your close to it or far away as we observed in my recent DIY projector project
so success right well to degree yes but the diameter of your lens directly dictates the
size of your area of projected sunlight so you need a massive lens to really get the
best out of it if you're using a single point light source. Even if you use lenses of the Fresnel variety
this can get pretty expensive and you still have some issues to contend with such as chromatic
aberration which is the rainbow effects you see at the edges thankfully however there's
another way of collimating mating light rays which is to use a parabolic reflector now
this just like a lens can take light rays admitted at its focal point and bounce them
back but in a way that collimates them to be perfectly parallel only this time without
any chromatic aberration or distortion – nice.

Reflectors like this are just as expensive
in hard to find as large lenses however or say you might assume until you realized that
there might be one already attached to the side of your house that's right satellite
dishes too are parabolic reflectors intended to amplify distant radio signals by focusing
them onto a single point. They are often off center designs which is why they're frequently
oval shapes rather than round. The best part about utilizing these though
is that used ones can be had for very cheap or even free if they're old and need replacing
I'm using a big one here that measures of 1.2 m in diameter which means that my area
of projected artificial sunlight will be the same size as this however as you can see it
isn't reflective to visible light so that's the thing we going to have to fix first.

One important thing to do before proceeding
however is to give it a good clean as this will get any dirt off which means that it
will be much better for the next step yours is super rusty like this one you will need
to give it a thorough sanding down before applying a rust covering primer both of these
prepping processes are important because we're going to be using vinyl mirror effect film
to give it its required reflectivity and we're going to cut it into strips so that it's easier
to apply.

You might be tempted to use some reflective
foil tape here instead but from my tests the mirror film is significantly more reflective
so it's definitely recommended and you can find links to some in this videos description
it does take quite a while to stick on in strips but once you're done you should have
something that looks like this with it now mirrored it's rather ironically very important
to stop any sunlight from ever hitting it as it could focus the light to a point and
start a fire so be careful so this is looking really promising but before we can test it
out and see whether it's going to successfully collimate the light rays we need to sort out
a light source for this we are going to be using a high power LED and as usual I recommend
that you get one with a CRI of a minimum of 90 but ideally 95 and a colour temperature
of 5600k now as these LEDs are so powerful they do generate heat which means that they
have to be used in combination with a heatsink now thankfully for 100w emitters you can get
away with using a computer heat sink which are super cheap to buy second-hand but for
this project I thought I would go with something a bit more special and I'm using a 500 watt
LED from Yuji LED and this is obviously very bright but also it gets very hot so it's accompanying
heatsink is unfortunately very oversized very heavy and very loud as well with internal
fan so instead of using this massive heatsink which would probably bend the satellite dishes
support arm I'm going to be instead water cooling the LED and the set of components
I have here are from alcohol and I'm going to be introducing them and their function
as I go along the first component we're going to utilise is a water block which internally
has a lot of tiny fins that the water rushes through taking heat away from the bottom plate
to interface this well with the LED and ensure good heat transfer some thermal compound can
be used and then the whole thing can be clamped together with a custom bracket no this is
actually going to be mounted in place of the satellite dish's original receiver so after
removing the original receiver a small bracket can be made out of a short length of aluminium
angle which allows the LED to be mounted in place of the original receiver at the same
position and angle if you're using a lower power LED and just want to use a heat sink
this process is pretty much identical and to power the LED you can just use a voltage
regulator and an AC adaptor and this is a very good low-cost way of getting a lot of
light output however as I'm using a much more powerful LED and water cooling the process
is a little bit more involved and to get water to and from my LED there are some standard
plumbing fittings on the back of the water block which allows some compression fittings
to be used to securely mount some rubber tubing in place which can then be routed down the
arm along with the LED's power wire now as the power supply musing for my LED is super
solid and heavy not to mention waterproof I made some custom brackets to mount the pump
and reservoir combo unit directly to it followed by the radiator and this can be hooked up
to the pumps inlet using a short length of tubing the pumps outlets can now be connected
straight up to the LEDs waterblock and then returned through the radiator completing the
loop so the last thing to do now is to fill it up this process can take awhile as it needs
to be done bit by bit running the pump in bursts to push the water into the loop if
you ever do this yourself be careful to never run it dry as it relies on water for lubrication
and it will likely get damaged if it's run without water in it so with water rushing
through now without any air pocket's some fans can be added to the radiator and the
LED is ready to try out honestly I forgot just how bright this LED it's pretty incredible
for being a single point light source but now it's time to mount it onto the satellite
to make a support for this I screwed some pieces of wood together to make a triangular
shape which made it fairly easy to lift the satellite dish up into position so as you
can see I've actually mounted the satellite dish upside down and this is so that we can
get a steeper angle on the light output so that it appears like it's coming from the
sky and not the ground and there is some really promising results actually from the reflection
coming off the mirror because the LED itself appears to stay the same size so that does
indicate to me that it is actually collimating the light but really we're just going to have
and see whether it works so I haven't actually tried this yet so I'm a little bit nervous
are you ready here we go ok ok you can't see this because you're probably blinded by the
light but yeah let me show you as you can see we have got parallel rays if I move my
hand close to the wall its shadow doesn't change in size no matter where I am in the
room which is pretty impressive looking in the general direction of the light source
it does look like it's at infinity which is super impressive I can't look at it directly
because it is a bit too bright but just looking in the general direction of the satellite
makes it seem apparent that it's in the distance which is super cool and what's more it's absolutely
pouring with rain outside which might seem irrelevant but the thing is it's sunny in
here for a bit more space I've actually moved the satellite dish out into the hallway and
as you can see the effect is really quite the remarkable this feels and looks just like
daylight and looking at the light not directly of course through the door it does appear
to be extremely far away so mission accomplished but there is one thing missing which is of
course the blue sky effect which is fairly significant because the sunlight look will
only properly come into fruition when the sky adds soft blue illumination to the room
so that's the thing we're going to have to sort out next but before we get on with that
it's time for a quick add from this video sponsor KiwiCo KiwiCo make super cool hands-on
projects and toys that are not only fun to construct but they're also very educational
and have been designed to introduce kids to Concepts in steam which is science technology
engineering art and maths so they're a great resource for learning with at home each box
contains everything you need for each project so it's completely self-contained with detailed
kid-friendly instructions and an educational magazine filled with content to learn even
more about each crate's theme now personally this kind of thing is right up my street and
I've said before that younger me would have absolutely loved kits like this as learning
in a hands-on way is far more interesting and far more engaging than learning something
from a computer screen or from a textbook and there's a whole different creative thought
process that you learn from it.

They have 8 subscription lines each catering to different
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and get a new box every month which can cancel at any point or a single gift which is great
for birthdays and special events and what's more is that if you go to kiwico.com you get
50% off your first order of any crate which is brilliant value especially with the holidays
coming up as they'd make great gifts so thank you KiwiCo for sponsoring this video and don't
forget to check them out with the link below so thanks to the satellite dish our artificial
sun is now at infinity reproducing parallel rays that look and feel like sunlight the
real challenge for this build is going to be mimicking a blue sky. The reason why the
sky appears blue is because molecules in the Earth's atmosphere actually bounce some of
the light coming in from the sun off their initial path which is a process known as Rayleigh
Scattering as this has a greater effect on shorter wavelengths blue light gets scattered
quite a bit while red light for example can pass through without being affected as much
this results in some of the white light from the sun diffusing into what we see as blue
sky leaving the sun itself to look more yellowy and warm as a result due to some of its blue
light being scattered outwards a great experiment for observing a similar effect at home can
be done by getting a glass of warm water and dipping in a little bit of soap as the soap
dissolves into the water it begins to scatter light in a similar way to the sky making it
look somewhat bluish looking through to a light directly behind it result in the light
appearing more orange because a lot of it shorter wavelengths are getting scattered
this smaller scale phenomenon is known as the Tyndall effect as it relies on much larger
particles compared to Rayleigh Scattering and can be seen in common materials such as
hdpe milk cartons and opalescent Glass now one of the best ways of achieving this effect
would be to use nanoparticles in some sort of epoxy resin however despite a ton of research
I haven't been able to find a good source of nanoparticles that work as well as this
so if you guys have any suggestions do let me know in the comments down below but for
this project my conclusion is that the best way is to simply use soap and water as it's
simple safe and effective however how are we going to get water into the shape of a
Window well we're just going to mimic a fish tank so for this we will need two sheets of
tempered glass and I suggest using an online calculator to work out what thickness you
need for the size of your window while it would be possible to glue these together with
a spacer to make a 4 mm deep watertight chamber I'm instead going to be using a gasket and
clamp the two pieces together with some 3D printed holders along with some washers and
bolts the plan here is to mount it directly to the back of a sheet of MDF which has been
painted to match the wall colour so that it blends in nicely around the door frame with
the satellite dish behind it in the hallway watching for any leaks some distilled water
can now be siphoned into the chamber making it ready for our soap mix I ran out of distilled
water at this point though so instead I used filtered tap water this does increase the
likelihood of soap scum forming after a day or two though which will need to be filtered
out in a couple of passes over a couple of days and this would be good practice to do
even if you use distilled water here and you may want to add a drop of biocide if you're
going for extreme longevity with the mix ready it can be injected into the window with a
plastic syringe that as the soap enters the chamber we can observe it instantly scattering
the light from an LED I placed behind the glass when you're doing this I do suggest
that you use the proper artificial sunlight to preview this instead but I wanted to leave
it for a big reveal over 24-hours the soap mix will spread out and become evenly distributed
so why not in the meantime finished the seen off with some light curtains to make it look
a bit more authentic right are you guys ready here we go.

Wow! Look at that! Look at that!
That really does feel like real daylight… goodness me! With the blue sky in place the light suddenly
becomes full of life and vibrancy, thanks in part to the sun taking on a warmer hue
due to the scattering, with the rest of the room being lit softly by cooler blue tones.
This has a dramatic effect on the overall feel of the light, and it genuinely fools
your brain into thinking that it's seeing specifically early morning sunlight both the
parallel rays and their subsequent scattering are necessary for this effect and neither
will work without the other so it makes for a perfect combination now one of the most
remarkable things about this light I would say is the way it makes you feel it's actually
night time right now and it's so close to real daylight then it's completely fooled
my brain and I feel fresh and awake and I'm doing the editing right now so that's kind
of important but I would imagine that something like this would be really helpful for people
with seasonal affective disorder which is where people feel really depressed in the
winter months where there's not much sunshine and you know this being basically the same
as real daylight should really boost people's moods so it could be quite useful in that
kind of situation I'd have thought but you even as a normal person it just feels so vivid
and full of life every home should have one of these especially in the long winter months
because honestly it's incredible I wish I could convey it enough to you but hopefully
my enthusing about it has done that but you really do have to see it in person to truly
appreciate it but it is truly remarkable photographers and filmmakers would also benefit hugely from
a light like this and I know that for my own work here on YouTube it's going to be a real
help to my filming so this is without a doubt an incredible bill however it is somewhat
large and while this wouldn't be a problem in a commercial environment or if you've got
a particularly large house I realise that for most of you building something like this
would be somewhat impractical however by taking a few compromises we can make it significantly
smaller now interestingly this compromise actually result in a few advantages as well
namely that it's much simpler to build requiring only basic tools and it all stems back to
earlier where I mentioned Fresnel lenses and how they'd have to be big and expensive to
work with a single point light source and what is true what we can do is divide it into
a grid and use multiple light sources and multiple Fresnel lenses in the form of super
cheap magnifying sheets and because they're all the emitting parallel rays they can work
together to achieve a very similar effect achieving a blue sky will be possible too
again going along with a compromise to make it much simpler to do so let's get to it before
starting we need to take a measurement of the Fresnel lenses focal length by using it
to project the real sun onto a rock to be a small as possible and then measuring the
distance with this measurement in mind we can now cut some foam board into lengths that
match it with the goal being to make the sides of a box each of the sides need to have some
light blue vinyl wrap adding to them which is for the blue sky effect once you have 5
of these panels the central one of which must have a hole made in it they can be stuck together
with some tape to make the box out of them like so the next thing will need is a 10 watt
LED and in my case I've already made this one on to a heat sink with some thermally
conductive glue one side of the LED can be powered from a voltage regulator and I've
got a whole video about how to set this up correctly in the description Now dabbing on
some hot glue onto the heatsinks legs it can be squashed against the outside of our box
with the LED showing through the hole that was made earlier with the LED been completely
unfocused its rays are not at all collimated so they diverge outwards as you can see as
soon as the magnifying sheet is placed on top with its ridges facing outwards however
things get pretty weird as it's distance to the LED matches the lenses focal length the
LED is collimated and thrown back to appear to be at infinity which is why the unlit LED
in this shot seems to be far down underneath floor and why it doesn't appear to change
in size these collimated parallel rays exit box and don't diverge which is why its throw
doesn't change in size either and why objects can't easily block the light projection looking
into this box reveals that we have a pretty decent blue sky effect although we can see
some lens flares from the Fresnel which does spoil the effect quite a lot when you're not
looking straight into it however it's remarkably effective for such a simple and cheap build
and it has all the major elements of the satellite version with only a few compromises here for
example you can see the gentle diffused blue working together with the main projection
of warm light and how it varies depending on the surface it lands on the idea with this
design is to make multiple copies is of them so that they can work together in tandem and
you can scale things up to be as big as you like alignment will never be perfect though
and you can see some cross over where the chromatic aberration causes some rainbowing
but shadows are consistent which is very nice and taking a look into the units themselves
shows how the virtual son is passed from one unit to the next depending on where you're
standing very cool indeed they can even be mounted together at an angle and hung a wall
to achieve a steep projection mimicking the summer sun so while it isn't as refined or
as bright as the proper satellite version it still has a very similar effect and considering
the effort involved it's absolutely worth it anyway whichever version you choose you'll
be amazed by the results and the satellite version in particular works phenomenally well
and will provide sunlight on demand for years to come so I hope you found this video interesting
and I hope my enthusiasm about this artificial sunlight has come over effectively because
it really is incredible and it's been such a long standing idea that I've had in my head
that it's just so wonderful to see it coming to fruition and I hope you agree that it was
worth the wait so many thanks must go out to every one of you for watching this video
and if you enjoy my content please don't forget to subscribe and if you want to support the
channel financially you can find the channels patreon account at patreon.com / DIY perks
and many thanks if you decide to support me on there but other than that I'm Matt, you've
been watching DIY Perks, and I hope I see you next time bye for now!

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