Please note that this is all written as if I had already created this projector. I have not. This is a projector design that I plan to bring to life when I gather the resources to do so. Parts bought online change in price often, so it is recommended that you do research for prices before buying and parts. Thanks for reading!
In the above pictures you can see a 2560x1440 resolution projector that I made for less than $275 (Not yet, I haven't made it). If you'd like to know what this would cost retail, you can click here. This high resolution, high frame rate (60Hz), high brightness, high contrast projector will cost around $275 total if you buy the parts from Asia wholesale rather than resale.
WARNING, PLEASE READ BEFORE STARTING:
PLEASE HANDLE ALL PARTS WITH EXTREME PRECISION AND CARE! FAILURE TO DO SO MAY RESULT IN PERMANENT DAMAGE TO ESSENTIAL PARTS! YOU WILL HAVE TO REQUEST A REPLACEMENT PART OR ORDER A NEW PART! ALSO, PLEASE FOLLOW THESE STEPS CAREFULLY TO MAKE SURE YOU POSITION PARTS CORRECTLY. DOUBLE-CHECK YOUR WORK.
Now that you know to be very careful, let's get started!
Step 1: Ordering the Parts
Let's get this clear first: All of these parts are being ordered from a different country off of a site that has little, bad, or no buyer-protection. Please order parts with DHL shipping (Not ePacket, China ordinary post, or small packet plus) when necessary. I will let you know when it is necessary. I also recommend you do some more research to see if you can find cheaper parts!
1x - 2560x1440 LCD ($210 Total; Shipping price may vary but probably not)
$100 for the LCD. $50 for the HDMI board. $50 for fast shipping (Is necessary so it is not damaged by bad quality shipping; Price may vary by location). $10 transaction fee. You must ask for a price quote for a sample of the HDMI board and LCD that has the back-light taken off of the LCD (It is too fragile and might break the pixels if you try to take it apart yourself).
1x - 1920x1080 LCD ($160 Total; Shipping price may vary but probably not). Buy this if you don't need 2560x1440 resolution. This is $50 cheaper.
$50 for the LCD. $50 for the HDMI board. $50 for fast shipping (Is necessary so it is not amaged by bad quality shipping; Price may vary by location). $10 transaction fee. You must ask for a price quote for a sample of the HDMI board and the LCD that has a back-light taken off of the LCD (It is too fragile and might break the pixels if you try to take it apart yourself).
1x - F200 to F210 Variable Projection Lens ($22.83 + Shipping)
$22.83 for the variable projection lens. Being variable allows the projector to focus manually without having to move the projector. $5.80 for shipping to Massachusetts; May vary by location.
1x - F120 Fresnel Lens ($4.50 + Shipping)
The Fresnel lens that is placed between the light engine and the LCD. $? for shipping to Massachusetts; Price may vary by location.
1x - F185 Fresnel Lens ($4.50 + Shipping)
The Fresnel lens that is placed between the LCD and the projection lens. $? for shipping to Massachusetts; Price may vary by location.
1x - 120W LED + Driver ($12)
The light engine (AKA: The 120 watt LED) and the driver combined. I bought either regular white or cool white; I think warm white might make the projected image yellow-ish so I chose cool white. The driver is to control the input of the light.
1x - Collimator + Reflector + Bracket ($3.58)
The reflector will position the light that tries to go backwards to go forwards in order to not waste any energy on unused light. The collimator will spread the light equally onto the first Fresnel lens. The bracket will hold it together.
1x - Heatsink + Fan ($10.67)
This will make sure that the LED doesn't overheat. With this particular projector's design, it will also create a cool airflow within the projector that will also cool the fresnel lenses and LCD.
1x - A bunch of wood that I'll add later when I actually make this thing. Or a different projector body material.
Total: $273.88 (will vary by what LCD you choose and how much shipping is for you)
Step 2: The Display
I don't have a HD video of the display but I have this:
Step 3: Understanding Some Terms
F200 : The F in F200 means Focal. The Focal length of lenses can be explained here (Probably in invision boards).
PJL : Projector Lens
Light Engine : The light source (The LED is the light source in this case).
F1 : The first Fresnel lens that lies between the light engine and the LCD.
F2 : The second Fresnel lens that lies between the LCD and the projector lens.
LCD : Liquid Crystal Display; This is a type of display (Like in your monitor, TV, or phone). It has an array of pixels and a back-light. The back-light is a rectangle that emits light that lies behind the array of pixels. It is what lights your display. We will remove this back-light so we can have the LED as a 'back-light' that will be projected.
LCD Board : The circuit board that controls the image data that is being sent to the LCD.
LED : Light Emitting Diode; A diode is a part that allows current to only flow one way. It is a diode that emits light. LEDs last longer than light bulbs and are more energy-conservative. They are less hot as well.
LED Driver : The circuit that regulates how much electricity is going through the LED.
Here is some more helpful information. You'll need to register.
Step 4: How I Calculated Everything (And Helpful Links)
Note: With the above pictures' data, the projected image should be ~91.4 inches diagonally. I guess I will see once I build this!
If you want, you can skip this step. It will help explain how I chose parts and found distances between those parts. This will include some great links to tools. It will also help you make your own projector if you want to design your own.
Here are some helpful links:
DIY Projector Forum (I think it is Filipino but mostly English speaking)
DIY Projector Calculator (This is French but open it in Google Chrome, right click on the page, and click "Translate to English")
The LumenLabs FocalCalc program is also helpful. Click the green 'Download Folder' arrow on the top right of the screen.
You can also look at other DIY Projector projects for some helpful data.
I basically used French projector calculator to choose all of my parts. You can see my input data and calculations in the images above.
If you want to help me build a better projector, use the french calculator I mentioned above to see if you can get the light output from center to corners to a higher percentage. I think the light output from center to corners is how dark the corners are compared to the center. I would like this to be higher than 70% as 70% I think is very noticeable. Thanks!
Step 5: Building a Concept Model in Google Sketchup
I can't get Sketchup to work now that I installed Windows 10. I will add this later when I get it working.
Step 6: Other Notes
I found this display board that converts HDMI input into MIPI DSI data for mobile displays. An iPhone 4 lcd is shown in the video below.
If you look at the Project logs on the project page, it shows that 17 days ago (from 7/8/15), the maker of this project has started production. He is targeting around $100 + tax/shipping. The rev 2.0 that is in production supports iPhone 4/4s LCDs plus the LG Optimus E980 LCDs. That is total ~$115 if you want a 1080p projector or ~$112 for a smaller 640p projector. This will be great once he starts selling! :)
PS: You can make your own one of these boards today if you know how to! He has provided everything you need to make your own, but it isn't as simple as making an Arduino UNO or Raspberry Pi.
The recent Kickstarter project C.H.I.P. is cheap and may be helpful in this and other projects.