Low-cost Homemade High-definition Projector

This DIY project started from scratch. I only studied mechanical design, but I'm an electronics enthusiast. Speakers, 3D printing, etc... I didn't take pictures of many details to share with you.

There are many areas for improvement, but the design was already finalized during the design phase.

Doing everything myself, from design to analyzing and interpreting technical data, gradually brought a sense of accomplishment. And personally, I feel it's comparable to a thousand-RMB phone! Thanks to Benlida for providing funding for this small project. And Gekunflex provides technical support!

1. Screen Driver Board
2. Condenser Lens
3. Screen
4. Fresnel Lens
5. Copper Pillar
6. Lens

Since this is a DIY project, a suitable casing couldn't be bought, so I had to design it myself. I used Rhino CAD for the design, and then handed it over to the acrylic cutting board maker.

First, before building this machine, I extensively researched other people's materials and drawings.

1. This is the casing drawing I made. Originally, I wanted to make a casing fixed with screws, but after thinking about it, I decided to make a snap-fit ​​casing.

2. The final drawing, showing the holes and corner holes for easy assembly. All the accessories have pre-drilled screw holes on the board! The drawings were mostly done in the early morning, my eyes were so tired!! Mostly done after get off work...

III. Initial Installation and Testing! Mostly done in the office!! Taking a break at work.

The LED light source and power supply are 100W, rated at 1100 lumens. Since I work for an LED lighting company, I'm very knowledgeable about light sources! The light source and heat sink were samples provided by other friends, so they were free!

The casing is black opaque acrylic sheet, as mentioned above! I designed the blueprints and had the sheet cut!

This is the LCD screen frame, using 10mm M3 threaded copper pillars to support the Fresnel lens.

The frame with the LCD screen installed. The design involved measuring the screen dimensions and drilling a 3mm through hole. One side uses screws and washers to hold the screen in place, and the other side connects to the copper pillar to hold the Fresnel lens.

The initial installation of the LCD screen and lens! Excellent!!

The LCD screen driver board and VGA interface haven't been installed yet. The driver board's mounting holes were designed correctly, but the LCD screen's ribbon cable wasn't long enough!! A design flaw!

A side view! Let me explain the purpose of those two large holes on the side. The designer used them to install a cooling fan, pre-installed with an 80mm fan (easily available on Taobao). One side intakes air while the other exhausts, circulating the cooling system.

The distance between the front and rear Fresnel lenses and the LCD screen is 10mm, because the copper pillars are also 10mm!

After installation and testing, as shown in the picture, the screen is upside down! It's reversed! This proves my theory was incorrect! I thought the three-sided mirror would refract and reverse the image, but it turns out I was wrong!

This test revealed many problems. First, the brightness is insufficient. The 100W LED light source doesn't have high light efficiency because there's no reflector, so the light emitted by the light source isn't fully projected onto the rear Fresnel lens.

Another problem is the optical axis is incorrect; one side is too dark and the other too bright, resulting in an uneven projected image. This is because the casing design didn't properly secure the heatsink. I will design a frame to fix the heatsink and center the optical axis in the future.

Here's where a fatal problem occurred: when I was inverting the screen, I tightened the screws too forcefully and crushed the LCD screen!! Lesson learned! Screens are very fragile and easily broken! Never use hard objects to press on them! So heartbreaking! A 5-inch LCD screen is ruined just like that; I'll have to buy a new one.

Afterwards, I used plastic gaskets—super soft, not easily damaged by pressure, and very tight!

The exciting part is here! After several major improvements, including sanding and drilling… the final assembled result was surprisingly familiar! At this point, the lighting was still uneven, with the center being brighter. This is because this was just a lighting test; the front mirror and LCD screen weren't installed yet.

Two fans were installed for heat dissipation: one blowing air from the side and rear towards the heatsink, and the other inside the case on the other side, drawing air outwards. This creates a circulation effect, keeping the 100W light source cool to the touch. Below is the screen driver, finally placed in this position.

After testing, I felt the appearance was still lacking something. Luckily, the factory had a laser engraving machine for engraving product logos, so I engraved the letters REIX and my name on both sides of the chassis...

Final REIX laser engraving effect on the left side! Impressive, isn't it?!

The light leakage was quite severe at first, but I sealed those edges with hot glue and it stopped. However, I ensured the top panel of the chassis is movable, allowing for future upgrades and accessories. Next to REIX is the projector's name in English, and below is my name and the date I DIYed the machine!

All the previous efforts have been for this moment!! The great moment is about to arrive! Power on!! Connect to the computer! Please ignore the messy office!

Turn off the lights and open Youku. Currently, it's about 60 inches. It's worth noting that the higher the LCD screen resolution, the better the projection effect—this is an age-old truth!

Lights off effect! Notice the horizontal line at the top, indicating a light leakage area. This problem has been solved!

I initially tried a 4:3 aspect ratio, but the effect wasn't good. A 480*800 screen is 16:10, and even adjusting it to 16:9 didn't provide the best effect. Plus, my office computer doesn't offer a 480*800 resolution option due to graphics card driver issues.

The image appears dark with the lights on because the wall absorbs too much light. With the lights off, the effect is minimal. For a truly immersive viewing experience, a screen is essential, preferably a high-quality one.

Sacrifice! The projector is approximately 70 inches at this point.

Because the projector lacks keystone correction and a stand, it's placed on a clothes rack. The board was designed with the centre in mind, so as long as the mounting holes are aligned, it's balanced.

Also, I'm using a 5-meter VGA cable! The white wall without a screen is still clear!

Finally, I wish all my DIY enthusiast friends could also create exactly what they want!