Building a TRUE 4k home cinema projector (it’s awesome)

Hi, I'm Matt and welcome back to The Advantages of DIY. In this video, I'll show you how to build your own

home

made

projector

and get this. Kay, you heard right, it's 4k, this one will be good. Despite being

home

made this

projector

packs a punch with sharp contrast, the image and vibrant colors are also fully Android enabled so it can work on its own without being connected to anything making it brilliant for Qing's online content with friends and family now later. We will compare the image quality to a commercially available movie projector that costs $2000 and believe me it is a bit shocking so stay tuned but before we start the

building

process I want to show you the basics of how projectors work .

Even with a basic level of understanding for this explanation, I am going to project a slide image which is basically a small transparent photograph when placed in front of a light source, all it does is project vague and blurry colors, so it is necessary to bring it. Focus with one lens here, although you might be surprised to see that the result is a single bright spot in the middle. This is because the lens only sees a single point of bright light, so the rest of the image remains dark as a result. To understand exactly what's going on here, we need to trace the light rays, so our setup Basic projector so far consists of a projection lens, an image and a light source, all the light rays radiate from this light source without direction, Aarthi, so the rays that actually hit the back of the Projection lenses are those that only pass through the middle of the image to rectify this and keep the light source close.

Projectors use an additional lens between the light source and the image setup to collimate the light rays to make them parallel and this results in the complete image that is now projected. The efficiency can be increased further with the addition of a converging lens that directs parallel rays directly towards the back of the projection lens, making the projection even brighter, so I hope you understand. The basic theory behind how projectors work and I think it's about time we built our own. Taking a look inside you can see that it is essentially made of different layers all held by four threaded rods to allow precise positioning during construction to make the layers themselves, I suggest using aluminum as it is cheap, strong and easy to work;

Each layer has to be a 20 centimeter square with a hole in each corner for the threaded rods to pass through. Now they also need various holes and cutouts made in them throughout the build depending on the components they support, but I will cover this as we go, so to start the frame we are going to make the base layer and as it will be visible externally , I will add some mats with black vinyl wrap. To do this, as it is quicker than painting and gives a good overall finish, we can now take one of the rods and thread a pillar spacer followed by the new black coating holding it in place with a covered donut, the space provided by the pillars should be added about four centimeters, so you may need to add a few of them to achieve this anyway.

Once the four threaded rods are secured in place, you can see that the dome knots function as feet to address the wobbly rods, although we can add the first one. additional layer which again can be held in place with some nuts, the space between these layers will be used to house various power cables, so a hole needs to be made for these cables to pass through later, so that with the frame internal now started, it is ready to be built and the first components we will add is the light source, for this we will need a 100 watt LED, a heatsink and the power board links, all of which can be found at the description of this video, since we want the projector.

To have vivid and vibrant colors I recommend choosing an LED with a high color rendering index or CRI, this means that you will spend a little more on it, but it is money well spent as it directly affects the final image significantly. One thing to consider when choosing yours is its diameter, however, as this will affect your choice of lens, I will go into this in detail later, but for now just keep in mind that the larger the surface area of ​​the LEDs, the the wider the lens aperture. it has to be either way as the LEDs are so bright they get very hot which is what the heatsink is for to use a computer CPU cooler it is ideal for this and the old ones can be found at line at quite affordable prices, its size might make some people think. which is overkill for this use case but is actually ideal as it will mean that the final projector will run quieter due to the extra cooling headroom provided by the large cooler which allows the fans to spin more slowly so To mount this heat sink we can place it on the top. from the base and thread four knots onto the rods to match the height of the heat sinks.

These serve to support a new layer and more nuts are used to hold it firmly in place, as you can see on this new layer. I've already added a hole for the LED to show through and a ventilation slot along one edge. This slot is the beginning of the airflow cooling path that will allow air to pass through the entire projector keeping it cool. It is an essential step and every layer needs one of these. anyway, once the LED has some wires soldered on it should be able to fit nicely into its hole, the heatsink can have a small dot of thermal compound added to its center and then held against the LED which gives as This keeps both components safe.

Instead, the LED can now be connected to your power board, which is effectively a voltage booster before you connect it, although you need to set it to the correct values ​​for your specific LED and you can find a full video on how to do this. this on the diy benefits bonus channel, you can find a link in the description of this video. By the way, a good place to mount this power board is under the base of the heatsink, as you can make contact with the heatsink here and take advantage of its cooling. skill, so once this is done and working, it's time to take control over these rays of light and literally bend them to our will.

Our goal here is if you remember to take the radiant light rays and first make them parallel and then direct them to where it is projected. The lens will later, instead of using large, expensive glass lenses, we will use what are known as Fornell lenses, which are basically flat lenses that cut the curvature required to achieve a much thinner and cheaper lens, and are usually They are made of plastic, they can be purchased as a specific set for DIY projector projects like this and I put a link to some in the description of this video, each one needs to be placed on its own layer and again, don't forget the ventilation slots now .

I made one of mine black to differentiate during this video so the silver one will act as a collimator lens making the rays parallel while the black one will act as a converging lens so the silver collimator lens must first be mounted on your place with your external Eldridge facing up to achieve collimation, it must be positioned precisely over the LED at its specified focal length, which for mine is 90 millimeters, if you don't know the exact focal length of yours or want to make sure that be absolutely precise and accurate, a good way to take this measurement before the LED is mounted in place can be done by reverse previewing the system.

To do this, place a piece of aluminum where the LED will provide a surface to focus on and then tilt the whole thing toward the Sun, our most distant light source. Now this will become very bright, so never look directly at the focused point. Instead, use a pin to poke a small hole through a piece of electrical tape. and then stick this over your smartphone camera to block most of the light and not damage the sensor. You can then preview what you're doing on the screen without even looking directly at the light. The goal here is to adjust the positioning of the lens so that it projects the Sun into a small spot.

When you are happy, take the measurement of this new position and write it down, as this is the

true

focal length of the lens, now just to show that this is a very intense point. of light, this dry rod burns spontaneously when it touches the focal point. Anyway, once it's all in place you can tell it's actually working as a collimator because the LED that's at its focal point doesn't seem to change size when you get pretty wildly close to it, it's essentially been set at infinity and it's like we're looking at it through a window when the LED is on, it affects the shadows in a similar way, they don't change size as you would expect. from a local light source, it goes between blurry and sharp anyway, after adding some pillar spaces, the next lens can be slid down, but this time with its smooth side facing up in this configuration, it takes the rays of parallel light and condenses them into one. point where the projection lens will be later for now, although it's time to work on the focusing system.

The way we are going to adjust the focus is by moving the image layer back and forth and this changes the distance between it and the projection lens, allowing us to keep the projected image sharp and sharp, this movement will be achieved taking advantage of the threaded rods that allow a very fine adjustment to focus. To start, we will need a layer with a large cut in the middle for light to pass through. through without obstruction along with, you guessed it, a ventilation slot, we first need to screw some small pillar supports into this layer as it is part one of two and we also need to add a piece of clear acrylic over the cutout to prevent the air. pass through it and instead it has to pass through the ventilation slot provided, so in order for each corner of this platform to go up and down in unison, we are going to use a set of four gt2 timing belt pulleys, but As you can see, I don't bite the rods, so we need to add some threads to them.

An easy way to do this is to get some threaded inserts and, well, they're a little too big, so a quick twist on a drill with a file trims them down and reduces the size. and can then be held in place with the grub screws. Now they can be bolted into place and to make them more synchronized we can use a gt2 timing belt. The two idler pulleys you see here help keep it nice and tight for a while. The fifth pulley that has a knob attached successfully keeps them all in sync, so once the second part is added, it will go up and down evenly and reliably. .

This second part is actually the most exciting part of the build, as it is in fact the vitally important image source. Now in my previous demo I used this little slide image and since it's transparent the light can just shine through it to be projected by the lens, but obviously we want to watch a video so we need some kind of screen to through which light can shine and you know what? That's what it works for, a small non-backlit LCD panel. Small LCD screens like this are used in smartphones and you can buy them on eBay along with a control board that adds an HDMI input, making it a high pixel density mini monitor.

Of course you can find links. to these in the description and they really aren't that expensive even for a 2560 by 1440 pixel panel which will provide a superbly sharp projected image and will certainly be good enough for most use cases so it's my recommendation, without a doubt However, this is the debut of this particular projector design. I want it to be something very special and the main feature I am looking for is 4k now, as you can imagine, 4k screens of this size are not at all common, but they do exist, as seen in 2015, Sony released a phone called see some major improvements.

Take a look at this macro image for example, it's a close up of a 1080p smartphone screen and we can see the individual pixels compared to the 4k Sony screen; however, you can see that there is a monumental difference. It will be interesting to see if we can retain this detail in the final projected image, so stay tuned for some in-depth testing later.My particular phone has a broken back, so it was actually a very cheap purchase on eBay. However, it is worth noting that this is notable. The 4k panel now appears to be available separately on eBay with an HDMI control board, although it is quite expensive.

I've put a link in the description if any of you are interested; However, anyway, if you also use a phone, even if it's just to keep costs down by using an old one you have lying around, you should make sure that one actually uses an LCD panel instead of something like an LED OR that would not work for this job and two it has to have USB OTG support so you can connect a mouse and keyboard to operate it remotely once everything is checked with those checkboxes checked the first thing you need to do is dismantle the phone just enough to reach the screen.

Online phone repair guides are great for this. and it's not very difficult, so with the body and screen now separated, we can mount the body to one of the layers using some right angle brackets. As you can see, I replaced the battery with a small voltage reduction board set to 4.2 volts. and I added a one farad capacitor to go with it, which helps with any peak power demand. I decided to do this because my particular phone doesn't allow battery charging when using USB OTG, so emulating an infinite battery is the only option I have. If you opted for an HDMI dashboard display instead of recycling a smartphone, it would probably have to be mounted here similarly for both display types, although we do need to remove the backlight system entirely, which usually involves just lifting up the various layers. and gently disconnecting the backlight strip to prevent it from lighting up, do not be tempted to remove the reflective layer that was stuck to the back of the screen, as this is the polarizing layer and the screen simply does not show up . anything, if it wasn't there with the various layers removed, now you can see that it's basically transparent, which means it's ready to be mounted on your layer.

I recommend using tape temporarily placed in place for this and then following up with some epoxy to make. It is permanent, it can then be slid down onto the focusing platform and screwed to your pillar supports, this now makes the gt2 pulleys captive, so adjusting the knob gives a very smooth and precise rise and fall . It's worth noting that this system is completely internal, making construction simpler. General notice of how the front of this layer is black, which is important since Lenz focuses on this particular layer anyway, with that gain almost done, meaning the last thing to address is the most important thing about the projection .

There are a few things to consider when choosing your lens, the most important being the image circle of the lens you see, while you can buy an old full frame SLR camera lens for next to nothing. SLR lenses are designed to cover a 36 by 24 millimeter frame. In fact, the same size of that small slide is used before. If we used one of these lenses on our projector, we would only see the center of the screen projected because our screen is much larger than what a full frame lens is designed for. To cover, what we need is an older type of lens known as a large format.

These were used in box cameras and older wet plate cameras and were designed with an image circle that was much larger than that of full frame lenses. This means that, while if you use a large format camera lens it will likely cover the entire phone screen with ease, even older ones have excellent optical quality and are very cheap on eBay. As usual, you can find the search terms link in the description if you need help finding them. However the thing to consider is your aperture, aperture defines how much light a lens lets through, so one would think that having a wider aperture would result in a brighter image no matter what, it's not for us because we have the converging lens which basically makes the aperture irrelevant as long as the aperture is physically wider than the LED shape, as I mentioned above, so for my LED, which is small at only 16 millimeters in diameter, a lens with an f9 aperture is fine and there is no loss of light.

If you were to use an LED with a larger diameter, you would need something like an f4 lens, which means it has a much larger aperture. Focal length is also important as your lens should have a shorter focal length than the Converging Lens we added above, this is so you can focus on the screen while still being in the optimal position for the converging lens. Once you have your lens, you can mount it on its own layer and slide it into place again in the position it is vital to get it working correctly. I tested mine before mounting the image layer in place, turning on the LED and moving the lens up and down until there were no vignetting or color fringing, just a perfect white square.

Then I took note of this. measurement that allows me to now confidently slide it into place at this current stage. One thing you may be noticing is that everything is pointing towards the ceiling. This is just part of the projector design because it keeps the projector space very small and to direct the light forward, we will simply use a mirror. Ideally, it should be a front-facing mirror, meaning the reflective surface is on top rather than behind a piece of glass. This dramatically increases image quality as it eliminates ghosting to keep it costing little, you may want to make one yourself from a standard mirror and it's actually quite easy to do.

You can find a link to a video on how to do it in the description. Either way, this mirror needs to be mounted on its own layer and fixed. to the projector at a 45 degree angle, this mirror also corrects the inverted image effect that occurs when light passes through a lens, so when mounting the screen you can place it in the correct position, so now we only have Some final touches we need to do before we can test it. These finishing touches start with routing the power cables to the base of mine. I extended a USB OTG cable so I can route the phone's USB port to a USB hub that will allow me to connect multiple devices for the phone to use, such as a keyboard or USB drive.

Also at this point you will need to add the fans which in my case are set to push air out from the central space and are also powered through a voltage regulator so they can be set to spin at a slower speed skipping them underneath it's very important that these bottoms actually push the air out this way and I'll explain why in just a minute as you can see I've also added an outlet to the bottom lastly you should stick a piece of plastic in front of the phone so that it blocks any light that might otherwise reflect off it and with that the projector core is complete to fit it in, we just need to make some aluminum side panels and add some vinyl wrap so that both sides are black, you will notice that there are some large square cutouts on them and their function is to allow air to come and go as the bottoms push the air out, which means that internally the projector has a slight pressure negative compared to the surrounding atmosphere, meaning air will gently enter these top cutouts zigzagging all the way down keeping each component cool.

This is particularly important for the screen, as it would otherwise be damaged by overheating. due to the amount of bright light hitting it from behind to prevent dust from getting in, however we need to glue some speaker cloth in place, this allows air to pass through quite easily but traps all the dust, it is slightly transparent, however, to block any stray light from the screen being visible through it, I suggest cutting some cardboard and covering them with vinyl wrap, after which they can be glued over the top of these vents, but with a large enough gap so that air can surround them.

By the way, using cardboard here is simply to allow the phone's Wi-Fi signal to pass through, which would otherwise be blocked if we used something like aluminum to mount them to the projector. I suggest making some 3D printed clips, but you could make them quite easily out of wood. Another thing I recommend is placing a piece of acrylic over the mirror and lens section to prevent it from getting dusty as well. I have magnetized the front grill so I can remove it and operate the phone. directly, if ever needed, once the excess threaded rod is trimmed and covered with some dome notes, the projector is complete now, before you test it and see how good its image quality is, it's time to a quick ad from this video sponsor, Skillshare, if you would like to learn a new skill, whether it's designing your own website to promote your hobby or business idea, learning how to write music, or even how to take amazing, eye-catching photographs, then Skill Share is a great place to start.

I have thousands of classes to choose from and they are easy to follow thanks to their concise step-by-step structure that takes you from the fundamentals to the ability to properly understand the topic at hand, for example, I have been struggling. to add more graphs and diagrams to my videos to help me convey ideas more effectively and to do this, I found the Animation with Ease class on Skillshare to be a huge help and will benefit me and the content I make over the years coming. If all of this sounds good to you, the first thousand of you to visit the link in the description will get a free two-month trial of premium membership so you can explore the entire website and start learning right away, and if you decide you like , just $10 a month if you sign up with an annual subscription, which is less than some people spend on coffee in a month, so learn today by visiting Skill Share via the link below.

To power the projector, what I recommend is that you use an old laptop. brick, all you have to do is make sure that it can produce 120 watts and you do that by multiplying its output voltage by its output amperage and once you've confirmed that it's going to work, you just plug it in and because I have I have a phone. I need to turn it on now. I've set the light to activate when the phone turns on, so at any time you should see it light up. There we go, so right now I can't see the projected image. and that's because the room is very bright, so I need to block it first.

I'm also going to adjust the focus so it's sharp on my screen, so with the room darkened, I'm going to take a look first. it's the sharpness and here we have the image that I showed you earlier with the 4k screen test versus 1080p screen and surprisingly you can see each and every pixel, which shows you that we are actually taking advantage of the full 4k panel here even from above . in the corners which is an attribute of the lens now the brightness is actually just right for a dark room but if you have a light on or even a window that is not covered it will completely kill the image and this is because The LCD panel actually still blocks quite a bit of light, so it's the best you can do with a setup like this, but for most people you should be fine thanks to the keyboard and mouse.

I can also operate it remotely and it's a full Android experience. making it a really great smart projector, the contrast and colors are also absolutely accurate, as you can see in these images, this is all thanks to the LED we are using now, what we are really interested in is the video playback and like everything else. It's fantastic, it's completely 4k with all the attributes I mentioned above. It's good, you can even stream videos directly from YouTube and to get good audio, all you need to do is connect external speakers through the phone's headphone jack, which in my case I extend it. towards the outside of the case, so this all looks great so far, but how does it compare to the commercial projector that literally costs ten times as much?

Let's take a look. The first thing worth noting is that the expensive projector has much higher brightness, although it also has much more fan noise when adjusting the exposure settings on the camera, you can see that the overall image is very comparable and I'll let you be the one. Judge regarding sharpness, the colors, however, don't look as vibrant, so it really shows the importance. of that LED, so I think the performance is quite remarkable, it's hard to convey on video how good it looks, butBelieve me, it compares remarkably to the commercial unit, now in terms of brightness, you might be tempted to add a reflector to focus more.

The light from the LED towards the back of the screen, but that doesn't actually work very well and can damage the screen because it actually reflects more heat back towards the screen than light, which creates a very bright hot spot and this is likely to damage it so don't do it, you might also be tempted to use a more powerful LED so instead of using a hundred watt LED you might want to use a 300 watt LED and while you can do this , it complicates the project because you need a more robust power supply, a more powerful LED driver and much louder fans because although you will need to deal with more cooling, particularly on the back of the LCD panel, I think using a 100 watt LED is the right balance because the brightness As a result it's perfect for watching a movie at night and it's very very quiet so I would say it's now if you want to build one of these yourself I will make available a PDF guide that contains All the sizes. and the tools you'll need as well as the guides for all the different components and additional tips and tricks so you can find them linked in the description in a few weeks, so other than that, I think that's it for this video.

Quite an epic project but the result is incredible, so I hope you enjoyed it and I hope to see you next time, but bye for now.