Projects Past: The 2007 DIY Projector

I've had many projects over the years, the most involved by far has got to be my DIY projector.  It is also my first serious project. By the end of it I had vastly improved my knowledge of optics, electronics, woodworking, and even a little thermal dynamics.

Research started sometime mid 2007, the now defunct lumenlab forums had a whole community of people building DIY projectors. There is a lot of theory to learn, optics to figure out, components to buy, and bringing all the pieces together is no simple task.  For such a complexe machine, at the core it has some very simple principles: A point light source radiates light into a fresnel lens, which straightens the light through the LCD screen, then another fresnel lens angles the light into a special lens which can focus the light on a screen. Here is an image from engadget which demonstrates the light path:


The major problem with these sorts of projectors is that they tended to be very large. 1080p monitors at the time tended to be at least 19" diagonal, which meant the entire box would need to be 3-4 feet long! Fortunately there were a few entrepreneurial types who started sourcing LCD screens that were smaller and ideal for DIY projection and selling them directly from the manufacturers. I managed to get my hands on one such monitor that was only 10.6" and had 720p resolution. With the LCD picked out I was able to begin designing the enclosure around December 2007.

Other than the LCD, the most important component is the light source. Some of the brightest bulbs consumed 400 watts of electricity or more, and had very impressive results. But with such high powered bulbs came a lot of heat that needed to be dealt with. I ended up going with a smaller 150 watt bulb.

The final pieces were the fresnel lenses and the projection lens. These were a fairly standard item and lumenlab took a lot of the guess work out of things by selling them from their store.

My final design to incorporate all these parts was a two chamber design.  The top chamber had the optics.  The bottom chamber contained all of the electronics: The LCD controller, the light bulb components (transformer and starting capacitor), and AC adapters and a heat sensitive trigger which would keep the fans running until the heat in the box dropped far enough.

The enclosure was designed to be simple to build and easy to assemble. The parts were cut on my dads table saw, and pieces were laminated together so that components could slide in and out of the enclosure during assembly. This design worked nicely.
In this picture you can see all the electronics (minus the thermal switch) and the various slots for the LCD, fresnel lenses, and chamber separators.

The LCD and Fresnel Lenses were built into frames that could easily slide into the slots:
The LCD frame had special protection for the delicate flexible cables of the monitor electronics. The frames for the fresnel lenses were similar.

The light source needs to be precisely positioned for the light to focus properly, so this box was built with rare earth magnets on the bottom. It attaches to a metal plate in the box which can be seen in the upper left of this photo.


The back was hinged so that adjustments could be made as needed, here you can also see the light box in place.


The triplet lens is another clever mechanism I came up with, by building the box a little loose I was able to pad it with felt so that the lens carriage could slide in/out but still be held snugly in place. The slot at the bottom was for a holding screw, but ended up being unnecessary.



Fully assembled, on the left is a front surface mirror which allows the box to be 11" deep instead of  nearly 30.


The final result is big and ugly, but it worked and I used it for years. I'll never forget how surprised my girlfriend was when I plugged it in for the first time and an image, apparently she thought I was crazy for those 5 months. In the end it really did work nicely. Designing it was a lot of fun, but my craftsmanship really limited my options.

More pictures can be found on my flickr page: DIY video projector


Comments

  1. Hey Will. I am looking for a video projector. Do you have one you would like to sell? I saw one on craigslist a while back.

    ReplyDelete
  2. It was really insightful.
    Thanks for such a nice content.
    Cheers
    BTW if anyone interested more have a look https://sawfinder.com thanks

    ReplyDelete
  3. When we find issues related to this type of subject that's not easy to find but some people like you make it easy for us. Thanks for giving us precious time. Projector Rental New Orleans

    ReplyDelete
  4. Great article, very useful and explanation. Your post is extremely incredible. as we provide audio hire Melbourne at affordable prices. for more info visit our website.

    ReplyDelete
  5. Very nice, i really like your blog and Very useful informations. Thankyou. we also provide Projector and Screen Rentals New Orleans with affordable price. for more information visit on our website.

    ReplyDelete
  6. Your article is valuable for me and for others. Thanks for sharing your information. get one of the best service for Projector and Screen Rentals New Orleans then visit on our website.

    ReplyDelete
  7. This post is really awesome. Genuinely i like this blog. It gives me more useful information. I hope you share lots of things with us. projector screen hire Melbourne

    ReplyDelete
  8. I am very grateful that I got some useful knowledge from this post. Thank you so much for posting it. Keep it up. electrical boxes

    ReplyDelete
  9. I am very obliged to you that you have shared this important information with us. I got some different kind of knowledge from your webpage, and it is helpful for everyone. Thanks for sharing it once again. Neodymium magnet manufacturer

    ReplyDelete
  10. Wonderful post. your post is very well written and unique. Thank you for sharing this post here. diametric magnets

    ReplyDelete
  11. Modern cars are coming with LED tail lights. Other than being brighter, they also look good on the back of the car. This is one more reason why you need to switch over to LEDs. If your car is an older version with incandescent bulbs, installing LEDs will most definitely up its aesthetics. protuninglab.com

    ReplyDelete
  12. When you bring your vehicle to an auto body shop for repairs, they can coordinate the repairs with the necessary parties to ensure that your damage is taken care of in the most stress-free manner possible. https://www.premiumcomponents.info/BMW-Bumpers-Headlights

    ReplyDelete
  13. You are providing good knowledge. It is really helpful and factual information for us and everyone to increase knowledge. Continue sharing your data. Thank you. enema bulb

    ReplyDelete
  14. This comment has been removed by the author.

    ReplyDelete

Post a Comment

Popular posts from this blog

Decommissioning the cloud: A self-hosted future

Using a JFileChooser to browse AWS S3

Taking Stuff Apart: Realistic Modulette-8