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

hello I'm Matt and welcome back to DIY perks in this video I'm going to be showing you how to build your very own homemade projector and get this it's or Kay you heard that right it's 4k this is going to be a good one despite being homemade this projector packs a serious punch with a sharp contrast the image and vibrant colors is also fully Android enabled so can operate on its own without it being plugged into anything making it brilliant for Qing online content with friends and family now later on I will be comparing the image quality to an off-the-shelf cinema projector that costs $2,000 and believe me it's a bit shocking so stay tuned for that but before we actually begin the build process I want to show you the fundamentals of how projectors works to the yet a base level understanding of it for this explainer I'm going to project a slide image which is basically a small transparent photograph when it's placed in front of a light source all it does is cast vague blurry colors so it needs to be brought into focus by a lens here though you might be surprised to see that the result is a single bright spot in the middle this is because the lens is only seeing a single bright point of light so the rest of the image remains dark as a result to understand exactly what's going on here we need to plot out the rays of light so our basic projector setup so far consists of a projection lens an image and a light source all the light rays are radiating out from this light source with no direction Aarthi so the Rays that actually hit the back of the projection lens are the ones that have only passed through in the middle of the image to rectify this and keep the light source close by 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 full image now being projected efficiency can be increased further with the addition of a converging lens which directs the parallel rays straight towards the back of the projection lens making the projection even brighter so hopefully you understand the basic theory behind how projectors work and I think it's about time we get to building ours taking a look at the inside you can see that it's essentially made of different layers all supported by four threaded rods to allow for accurate positioning during construction to make the layers themselves I suggest using aluminium as it's cheap strong and easy to work with each layer has to be a 20 centimeter square with a hole in each corner for the threaded rods to fit through now these also need various holes and cutouts made in them throughout the build depending on what components they support but I'll cover this as we go along so to start the frame off we're going to make the base layer and as this will be externally visible I'm going to add some mats black vinyl wrap to it as it's quicker than painting and gives a good overall finish we can now take one of the rods and thread a pillar spacer onto it followed by the new black layer clamping it in place with a capped doughnut the spacing provided by the pillars needs to add about four centimetres so you may need to add a few of them to achieve this anyway once all four threaded rods have been clamped in place you can see that the dome knots function as feet to address the rods wobbling around though we can add the first additional layer which can again be clamped in place with some nuts the space between these layers will be used to house various power wires so it needs a hole made in it for these wires to pass through later so with the internal frame now started it's ready to be built upon and the first components we're going to add is the light source for this we'll need a 100 watt LED a heat sink and the power board links to all of which can find in this video's description as we want the projector to have vivid and vibrant colors I recommend choosing an an LED with a high color rendering index or CRI this does mean that you'll be spending a bit more on it but it's money well spent as it directly affects the final image in a significant way one thing to consider when you choose yours is its diameter however as this will affect your lens choice I'll be going into this in detail later but for now just take it that the larger the LEDs surface area the wider the aperture opening on the lens has to be either way as the LEDs are so bright they do get very hot which is what the heatsink is for using a CPU cooler from a computer is ideal for this and old ones can be found online quite cheaply its size might lead some to think that it's overkill for this use case but it's actually ideal as it will mean that the final projector will operate more quietly due to the additional cooling Headroom provided by the large cooler allowing for slower spinning fans so to mount this heatsink we can place it on top of the base and thread four knots onto the rods so that they match the heat sinks height these are for supporting a new layer with more nuts being used to tightly clamp it in place as you can see on this new layer I've already added a hole for the LED to see out through and a vent slot along one edge this slot is the start 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 vents anyway once the LED has some wires soldered to it it should be able to fit nicely into its hole the heatsink can then have a small dot of thermal compound added to its center and then be clamped against the LED resulting in both components being held securely in place the LED can now be hooked up to its power board which is in fact a voltage booster before this gets hooked up though you need to adjust it to the correct values for your specific LED and you can find an entire video on how to do this on the DIY perks extra channel a link to it you can find in this video's description a good place to mount this power board by the way is underneath the heat sinks base as it can make contact with the heatsink here and take advantage of its cooling ability so with that done and working it's time to take control over these light rays and quite literally bend them to our will our goal here is if you remember to take the radiating light rays and first make them parallel and then direct them to where the projection lens will be later instead of using large expensive glass lenses for these we're going to use what are known as Fornell lenses which are basically flat lenses that slice up the required curvature to achieve a much thinner and cheaper lens and they're usually made out of plastic they can be bought as a set specifically for DIY projector projects like this and I've put a link to some in this video's description each one needs to be fitted onto its own layer and again don't forget the vent slots now I've made one of mine black to differentiate it during this video so the silver one is going to act as the collimator lens which makes the Rays parallel while the black one is going to act as the converging lens so the silver collimator lens needs to be mounted in place first with its foreign Eldridge's facing up to achieve collimation it does need to be precisely positioned above 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 you want to make sure that it is absolutely precise and accurate a good way of taking this measurement can be done before the LED got mounted in place by doing a reverse preview of the system to do this place a scrap piece of aluminium where the LED goes to provide a surface to focus on and then tilt the whole thing towards the Sun our most distant light source now this is going to get very bright so never look directly at the focused point instead use a pin to poke a tiny hole through a piece of electrical tape and then stick this over your smartphone's camera to block most of the light so that you don't damage its sensor you can then preview what you're doing on the screen without ever looking directly at the light yourself the goal here is to adjust the positioning of the lens so that it projects the Sun into a single tiny dot when you're satisfied take the measurement of this new position and note it down as this is the lenses true focal length now just to prove that this is a very intense point of light this dry stick spontaneously combusts when it touches the focal point yikes anyway once it's all in place you can tell that it is in fact working as a collimator because the LED which is at its focal point doesn't appear to change in size when you move closer to it pretty wild it's essentially been pinned at infinity and it's like we're looking out at it through a window when the LED is lit up it affects shadows in a similar way they don't change in size like you would expect from a local light source it just goes between blurry and sharp anyway after adding some pillar spaces the next lens can be slipped down but this time with its smooth side facing upwards in this configuration it takes the parallel light rays and condenses them down to a single point where the projection lens will be later for now though is time to work on the focusing system the way we're going to adjust focus is by moving the image layer forwards and backwards and this changes the distance between it and the projection lens allowing us to keep the projected image crisp and sharp this movement is going to be achieved by taking advantage of the threaded rods allowing for very fine adjustment to focus to start this off we'll need a layer with a large cutout in the middle for light to pass through unobstructed along with you guessed it a vent slot we need to screw a few small pillar supports onto this layer first though as it's part one of two and it also needs to have a piece of clear acrylic added over the cutout so that air is prevented from passing through it and instead has to go through the provided vent slot so to get each corner of this platform to rise and fall in unison we're going to utilize a set of four gt2 timing belt pulleys but as you can see they don't bite the rods so we need to add some threads to them an easy way of doing this is to get some threaded inserts and it's oh well they're slightly too large so a quick spin in a drill with a file trims and down to size and then they can be clamped in place with the grub screws nice these can now be screwed down in place and to make them more synchronized we can use a gt2 timing belt the two idler pulleys you see here help to keep it nice and tight over a fifth pulley which has a knob attached this keeps them all successfully synchronized so once the second part is added it will rise and fall 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 demonstration earlier I used this little slide image and as it's transparent light can just shine through it to be projected by the lens but obviously we want to watch video so we need some kind of screen that light can shine through and you know what works for that a small LCD panel with its backlight removed small LCDs like this are used in smartphones and you can buy them off eBay along with a control board that adds an HDMI input making it a high pixel density mini monitor you can of course find links to these in the description and they're really not that expensive even for a 2560 by 1440 pixel panel that will provide a superbly sharp projected image and will be certainly good enough for most use cases so is my recommendation however this being the debut of this particular projector design I want it to be something extra-special and the headline feature I'm going for is 4k now as you can imagine 4k screens of this size are not at all common but they do exist you see way back in 2015 Sony released a phone called the Xperia z5 premium and it featured rather ridiculously a 4k screen now 4k at this screen size is just absolutely wasted because you can't see any benefit of it but because we're going to be blowing it up by about a thousand times we should see some serious 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's a monumental difference so it's going to be interesting to see whether we can retain this detail in the final projected image so stay tuned for some in-depth tests later my particular phone has a smashed back so was actually a very cheap eBay Buy it is worth noting though that this remarkable 4k panel does now appear to be available separately on eBay with an HDMI control board though it is rather expensive I've put a link to it in the description if any of you are interested however anyway if you too to use a phone too even if it's just to keep costs low by using an old one that you have lying around you need to make sure that one it actually uses an LCD panel rather than something like an O LED which wouldn't work for this job and two it has to have USB OTG support so that you can plug in a mouse and keyboard to operate it remotely once it's all boxed in with those check boxes checked the first thing to do is dismantle the phone far enough to reach the display online phone fixing guides are great for this and it's not terribly 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've replaced the battery with a small voltage step-down board set to 4.2 volts and added an accompanying one farad capacitor which helps with any power demand spikes I decided to do this because my particular phone doesn't allow for the battery to be charged when USB OTG is in use so emulating an infinite battery is the only option I have if you went with an HDMI control board display instead of recycling a smart phone if would likely have to be mounted here in a similar way for both screen types though we need to remove the backlight system entirely which usually involves just lifting the various layers out and delicately disconnecting the backlight strip to stop it from illuminating don't be tempted to peel off the reflective layer that stuck to the back of the screen though as this is the polarizing layer and the screen just wouldn't display anything if it wasn't there with the various layers removed you can now see that it's basically transparent meaning that it's ready to be mounted onto its layer I recommend using tape told it temporarily in place for this and then following up with some epoxy to make it permanent it can then be slid down on top of the focusing platform and screwed to its pillar supports this now makes the gt2 pullies captive so that adjusting the knob results in there very even and precise rise and fall it's worth noting that this system is entirely internal which makes the build simpler overall notice to how the front of this layer is black which is important as this particular layer is brought into focus by lenz anyway with that win nearly finished meaning that the last thing to tackle is the all-important of projection lands there are a few things to consider when choosing your lens the most important being the lens's image circle you see while you can purchase an old full-frame SLR camera lens for next to nothing SLR lenses are designed to cover a 36 by 24 millimeter frame the same size in fact of that tiny slide are used earlier if we were to use one of these lenses in our projector we would only see the very center of the screen projected because our display is so much larger than what a full frame lens is designed to cover so what we need is an old lens type known as large format these were used in old box cameras and wet plate cameras and were designed with an image circle that was way larger than those of full-frame lenses this means that so long as you use a large format camera lens is likely to cover the entire phone screen with ease even ancient ones have great optical quality and are very cheap on eBay you can as usual find the search terms link in the description if you need help finding them one other aspect to consider however is its aperture the aperture defines how much light a lens lets through so you'd think that having a wider aperture would result in a brighter image no matter what right well not for us because we've got the converging lens that basically makes the aperture irrelevant so long as the aperture opening is physically wider than the LED way using like I mentioned earlier so for my LED which is tiny at only 16 millimeters in diameter a lens with an f9 aperture is fine and there's no loss of light if I were to use an LED with a larger diameter it would necessitate the need for something like an f4 lens which means that it has a much bigger aperture focal length is important too as your lens needs to have a shorter focal length than that of the converging lens we added earlier this is so that it can focus on the screen while still being in the optimal position for the converging lens once you've got your lens it can be mounted onto its very own layer and slid in place again the position of it is vital to get it to work properly I tested mine before mounting the image layer in place by having the LED lit and moving the lens up and down until there was no vignetting or color fringing just a perfect white square I then took note of this measurement allowing me to now confidently slide it right down in place at this current stage now one thing that you might be noticing is that everything is pointing upwards towards the ceiling this is just part of the projectors design because it keeps the projectors footprint very small and to direct the light forwards we're going to simply use a mirror ideally this needs to be a front surface mirror meaning that the reflective surface is on the top rather than behind a piece of glass this increases image quality dramatically as it eliminates ghosting to keep costs low you might 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 about how to do it in the description either way this mirror needs to be mounted onto his own layer and fixed to the projector at a 45 degree angle this mirror also corrects for the flipped image effect that's caused when light passes through a lens which is why when mounting the screen you can just put it the right way up so now we've just got a few finishing touches to make before we can try it out these finishing touches start with routing any power wires down to the base for mine I extended a USB OTG cable so that I could route the phone's USB port down to a USB hub which will allow me to plug in various devices for the phone to utilize like say a keyboard or a USB Drive also at this point you will need to add the fans which in my case are both configured to push air outwards from the central gap and they too are powered through a voltage regulator so that they can be set to spin at a slower speed by under vaulting them it is very important that these funds do indeed push air outwards like this and I'll explain why in just a minute as you can see I've also added a power socket on the bottom lastly a piece of plastic needs to be glued in front of the phone so that it blocks any light that might otherwise reflect off it and with that the core of the projector is complete to box it in we just need to make some aluminium side panels and add some vinyl wrap to make both sides black you'll notice that there are some large square cutouts in them and their function is to allow air in and out you see because the funds push air outwards it means that internally the projector has a slight negative pressure compared to the atmosphere around it this means that the air will gently pull into these top cutouts zigzagging all the way down keeping each component cool this is particularly important for the screen as it would otherwise get damaged from overheating due to the amount of bright light that hits it from behind to stop dust from entering however we need to glue some speaker fabric in place this allows air to pass through easily enough but does catch all the dust it is slightly transparent however so to block any stray light from the screen from being visible through it I suggest cutting out some cardboard and covering them with vinyl wrap after which they can be glued over the top of these vents but with a spacing gap large enough air to still go around them the reason for going with cardboard here by the way is merely to allow the phone's Wi-Fi signal to pass through which would otherwise be blocked if we used something like aluminium to mount these onto the projector I suggest making a few Clips my 3d printed mine but you could quite easily make these out of wood another thing I recommend is placing a piece of acrylic over the mirror and lens section to stop it from getting dusty too and I've made the front grille magnetized so that I can take it off and operate the phone directly if ever needed once the excess threaded rod is trimmed off and capped off with some dome notes the projector is complete now before we try this out and see just how good its image quality is it's time for a quick ad from this video sponsor Skillshare if you'd like to learn a new skill whether it be designing your own website to further your hobby or business idea to learning how to write music or even how to take amazing eye catching photographs then skill share is a great place to start they've got thousands of classes to choose from and they're easy to follow thanks to their concise step-by-step structure that takes you through from the fundamentals right on to being able to properly understand the topic at hand for example I've been endeavoring to add more graphics and diagrams into my videos to help me to convey ideas more effectively and to do this I found the animating with ease class on Skillshare to be a massive help and it will benefit me and the content I make for years to come so if all this sounds good to you the first thousand of you to visit the link in the description will get a two month free trial of premium membership so you can explore the entire website and start learning right away and if you decide you like it it's just $10 a month if you subscribe with an annual subscription which is less than what some people spend on coffee in a month so get learning today by visiting skill share through the link below [Music] now to power the projector what I recommend is they use an old laptop power brick all you've got to do is make sure that it can output 120 watts and you do this by multiplying its output voltage by its output amperage and once you've confirmed its going to work you just plug it in and because I've got a phone I need to turn it on now I've set the light to be triggered when the phone turns on so any moment now you should see it light up there we go so at the moment I actually can't see the projected image and that's because the room is so bright so I first need to block it out I'm also going to adjust the focus so it lens sharp on my screen so with the room blacked out the first thing I'm going to take a look at is sharpness and here we've got the image I showed you earlier with the 4k screen versus 1080p screen test and amazingly you can see each and every pixel which shows you that we're actually taking advantage of the full 4k panel here even right up to the corners which is an attribute of the lens now the brightness is actually just about right for a dark room but if you have a light on or even a window that's not covered it will completely kill the image and this is because the LCD panel actually does still block quite a lot of light so it's the best you can do really with a setup like this but for most people it should be just fine thanks to the keyboard and mouse I can operate it remotely as well and it's a fully fledged Android experience making it a really cool smart projector contrast and colors are absolutely on point too as you can see in these images this is all thanks to the LED we're using now what we're really interested though is in video playback and just like everything else it's fantastic it's fully 4k with all the attributes I've mentioned previously nice you can even stream videos directly off YouTube and to get good audio all you need to do is plug in external speakers through the phone's headphone socket that in my case I extend it to the outside of the case so all this is looking great so far but how does it compare to the commercial projector that literally costs ten times the price let's have a look the first thing worth noting is that the expensive projector has a much higher brightness although it also has a lot more fan noise adjusting the exposure settings on the camera you can see that the overall image is very comparable and I'll let you be the judge regarding sharpness colors however don't look as vibrant so it really shows the importance of that LED so I think that that performance is pretty remarkable it's hard to convey over video just how good it looks but trust me it stacks up to the commercial unit remarkably well now brightness wise you might be tempted to add a reflector to focus more of the light from the LED towards the back of the screen but that actually doesn't work very well and can potentially damage the screen itself because it reflects actually more heat towards the screen than it does light resulting in a very bright hot spot and this will likely damage it so don't do that 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 could do this it makes the project more complicated because you need a beefier power supply a beefier LED driver and much louder fans because though it will need to deal with more cooling particularly on the back of the LCD panel so I think that using a 100 watt LED is just about the right balance because the brightness resulting from it is just about right for watching a movie at night and it's very very quiet so I would say it's just now if you do want to build one of these yourself I will be making a PDF guide available for it which contains all the measurements and the tools you'll need as well as the guides for all the different components and extra tips and tricks as well so you can find that linked in the description in a few weeks so other than that I think that's it for this video it's been a pretty epic project but the result is amazing so I hope you enjoyed it and I hope to see you next time but bye for now

Channel: undefined

Views: 4,517,312

Rating: 4.9455733 out of 5

Keywords:

Id: YfvTjQ9MCwY

Length: 28min 20sec (1700 seconds)

Published: Mon Jun 15 2020

Reddit Comments

[u/PeanutButterChicken]

*Before clicking "Oooh, I have an Xperia Z5 Premium sitting in a drawer"

*After clicking "Ooh, that Z5P is going to stay in that drawer!"

[u/F7R7E7D]

DIY perks is a wonderful channel. That guy's brilliantly creative and resourceful (and always cheery, which is nice, he clearly enjoys what he does), his entire YT channel is amazing, highly recommend!

[u/infinifunny]

This guy totally reminds me of the actor playing Theon Greyjoy

[u/schemingraccoon]

Wow. This was beautiful to watch. Cant imagine the technical knowledge needed to build one though.

[u/JohnnieTech]

Impressive build but the vignetting is pretty bad. I'd like to see R, G, and B shown separately as a single color source. That being said, I'm pretty happy with my Xiaomi 1080p projector that definitely has blurry corners and vignetting. The problem is I paid $180 for it, which is way below this budget. I do love Matt's ingenuity with all of this projects and he certainly gives me some good ideas for future projects.

[u/kevingattaca]

I needed to know HOW MUCH his cost before the Video started... Just saying :(

[u/wavefrost]

At around 20 minute mark he says the fans are pushing air out, when in reality they are pulling air in. Air moves to the fan motor and not vice versa. Also indicated by the arrows present on the fans @20:08.

[u/[deleted]]

adding up all the components he listed, cost is >~600... wild...

i guess it repurposes the phone, but 600$ can get u a really nice projector..

edit: those downvoting, are you suggesting that $600 cannot get u a nice projector... i aint saying what this guy did is pointless or w/e, i think it's very cool...

[u/pokeblue992]

I just watched that this morning. Cool dude.