Building your own DIY projector
Why build your own projector?
I wanted a projector for many years , there was just one problem. Even the cheaper ones are expensive to use the way I wanted to use them. The reason being is that the bulbs in projectors last from 2000-4000 hours . Sounds like a lot until you consider I wanted to use it for tv, movies, videogames and as a computer monitor. Then consider that the bulbs are about half the cost of the projector usually between $200-$400. Projectors you buy are intended to be used for presentations or the occasional movie not as your primary viewing screen.
Then I discovered DIY projectors through Lumenlab. Turns out you can build your own projector for around $250-$400. To top that the bulb lasts 20,000 hours and costs $45 to replace. It has a resolution of 1024 x 768(480p) and about 1700 lumen's. That's just the basic model you can spend a little more and get full 1080p HD and more lumen's. I can tell you the number one reason to do this for me was, it was a lot of fun and I ended up with something I built myself that people cant believe. Anyone who can use a few simple tools can do this.
So to recap why you should do this
1. Its less expensive
2. It Lasts longer
3. Its a lot of fun
4. you end up with something you will use and feel proud of
What you will need for your projector
This project can be as simple or complex as you want it to be. I am not going to explain all aspects of these DIY projectors. I will outline what's involved and share my experience with you. If you really want to delve into everything that's possible in a DIY projector i suggest you browse around the Lumenlab forums. They also have a store that sells a lot of the lenses and electrical parts you will need. It's a little more costly to buy everything from them, but you pay for the convenience. Most everything else you can buy strait from your local hardware store.
You will need access to some basic hand and power tools. Including screwdrivers, saw, drill, skill saw, hole saw, tape measure, and a Dremel tool is handy. You will also need a can of compressed air ,and optical cleaner for glasses ,or LCD screens. To keep all your Lenses and your LCD nice and clean.
Remove the LCD
15 inch LCD Monitor
The basic design of a simple DIY projector is based around a 15" LCD monitor. You can find a selection of them on E-Bay for around $50 or you might have one laying around. There is a list of monitors here that will tell the specs of the monitor you are thinking of using and if it has FFC(flat flexible cable). If it has FFC it can add some extra work to the project. Keep in mind that the list is ongoing so it doesn't have all monitors on it. The best monitors for this project have 16 ms or less response time and the higher the contrast ratio the better. You need the actual LCD from inside the monitor which is transparent once you remove the back light and is what makes this project possible. You must be very careful with the LCD as they can be very delicate once removed. You will also need to keep the electronics that are connected to the LCD.
Keep these clean
You will need three lenses.Two frensel lenses the same size or slightly bigger than the monitor and a triplet lens the correct FL(focal length) for the size of screen and distance from the screen. The focal length of the triplet for the basic projector is 320fl. The focal length of the fresnel lenses are 220fl for one and 330fl for the other. Keep the lenses as clean as possible at all times. avoid touching them with your fingers.
The basic mechanics of it works like this. The light projects out of the bulb in a cone , hits the first fresnel lens which bends all the light straight through the LCD screen. It then hits the second fresnel lens which bends it back into a cone and focuses it on the triplet lens. Which in turn refocuses the image into the proper size and shaped cone to make a clear image the size you require on the wall or screen.
Bulb and ballast
The light source for you projector will come from a 400 watt medal halide bulb and a ballast to power it. There are many different types of bulbs. What is important is its color spectrum. The best color spectrum for a projector is around the 6500k. The Coralvue 400w e39 6500k is perfect for this. You can purchase the bulb and ballast from Lumenlabs or you can also find them at aquarium supply stores. Don't forget a mogul socket to mount your bulb to.
Cooling and safety
The lighting system can get very hot and you are going to want some kind of safety device that will cut power to the ballast if things get too hot. This is to prevent any fires from unattended projectors. Also to protect your fresnel lens and LCD which will crack if exposed to temperatures over 100 degrees Fahrenheit. A Thermostat assembly from an attic fan will work for this if the ballest is placed inside the projector. A grow light overheat shut off module will also work if you are placing the ballast outside the projector in a remote location, but is more expensive.
You are also going to want a piece of heat resistant lexan, or tempered glass to put in front of the first fresnel lens. This also keeps the fresnel and LCD from Getting over heated and protects them from the UV light coming from the bulb. Also you need some sheet metal to protect the inside of the box where the bulb is.
In order to keep the lighting system from getting hot to begin with you are going to need a fan or two, and a 12 volt power supply to run it. You can find 12 volt fans at computer supply stores and there are plenty of 12 volt power supplies to be had at second hand stores or your local Radioshack. Once again all this is available from the Lumenlab store.
Basic projector plans
Construction of DIY projector (click to enlarge)Click thumbnail to view full-size
Building the projector
These are the basic plans for a simple projector.The box is is made of wood with all inside surfaces painted flat black to cut down on reflection. Its important that everything is lined up on center. Also making everything adjustable fore and aft will save you some headaches if it doesn't come out right the first time. It is especially necessary that the triplet lens at the front is able to be adjusted for and aft. That is how you will focus the image. That can be accomplished by installing it in a tight fitting hole with a felt gasket for a small amount of adjustment, or you can make the whole front of the projector the triplet is attached to slide back and forth for a large amount of adjustment.
The box needs to be ventilated. That's what the fan is for, but it needs an inlet to work. The best way to cool your box is to make an opening in the top in between the first fresnel and the LCD screen. If you leave a gap between the bottom of the first fresnel and the bottom of the box, The air will then be pulled in between the first fresnel and the LCD. Then it will be pulled through the light area , across the bulb and finally out the back. If this is done correctly only one 120mm fan will be needed to cool your projector. You are going to need to create a filter to go across your inlet ,or your projector will get dirty inside real fast and they are not fun to clean out. A filter can be made out of static heating vent filters from your local hardware store.
There are a few other things you may want to look into. Including reflectors and AG(anti-glare) removal for more lumen's. Also a system for allowing the front fresnel to swing freely from the top , so it will automatically adjust the projection shape as you tilt the projector(keystoning).
This is just a short introduction to DIY projectors.There is a lot of information not included here that you can find for yourself. This is a great hobby and can become an obsession for some as there are many configurations and modifications that can be done to improve upon this basic design.
These projectors perform very well with a high quality image and are quite sturdy. Mine has been running nonstop for two years and I use it for everything including writing this hub. Here is a link to my Plog on lumenlab forums
Remember to be careful. Anytime you are working with power tools and high voltages you must take the necessary safety precautions.
Update 2014: wow this Hubpage is really popular still after 6 years. I have not been back on here for ages. As far as I know Lumenlabs closed down though I am sure you can still source all these parts pretty easily
I ran that projector 24/7 for 4 1/2 years. I changed the bulb one time. Then the Optima HD60 came out with 1080p 3D for a grand on sale. With an $80 replacement bulb.
So my DIY projector is still functional, but its has become obsolete.
Still a great project though. Always fun to build things yourself