There was a time – not long ago – when the only way to enjoy big screen TV entertainment was to invest several thousand dollars in an expensive rear projection TV or video projector. It was a time when many tried to experiment with DIY setups to produce a ‘dim’ big TV image on a wall.
This is no longer the case; now it is possible to get a bright SVGA projector suitable for DVD viewing for no more than a few hundred dollars. Yet it is still fun producing a life-size TV image for just a few bucks! DIY projection TV can make this a reality but…
DIY Projection TV: Does it still make sense?
You may wonder why we have decided to discuss DIY projection TV when in reality home theater is such a high-tech domain.
But up to a few years ago, investing in a video projector capable of 100-inch image projections called for at least three to four thousand dollars. Not everyone’s budget was up to a brand video projector unit — at least initially when setting up a home theater. Many had to live with their mid-sized TV until they were in a position to invest in a big screen projection television or flat-panel HDTV.
In these circumstances, a DIY projection TV unit would have surely appealed to many as a possible temporary solution. It is no surprise therefore that there used to be a lot of publicity on the Internet about Big screen DIY projection TV plans. It was a time when a number of on-line companies started promoting various TV projection plans to help you build a projector unit capable of projecting your TV image on a wall. The adverts claimed that these do-it-yourself projection TV plans could convert any TV into a 100- to a 150-inch big screen television!
In the midst of the fierce competition that cropped up in the process, some companies started advertising even bigger screen sizes as well. Often, these adverts gave the impression that a simple DIY projection TV set-up can be a direct replacement to a commercial home theater video projector costing at least a few thousand dollars more. Surely, creating big projections through a DIY projection TV setup is possible…
But what about picture quality and image brightness issues?
As we have stated, these DIY TV projector TV plans emerged at a time when prices of big screen TVs and home theater projectors were still out of reach of many. Things changed and 65-inch plus HDTVs and video projectors capable of 100-inch image projections have become a real mass-market preposition, making DIY projection TV more of a ‘fun experiment’ in optics than a quality solution to big screen entertainment in the home.
We therefore thought it would be interesting to reveal both the ‘mystery’ behind DIY projection television operation, and the limitations behind do-it-yourself projection systems.
Why so much interest in DIY Projection TV …where is the catch?
The most appealing issue here is the minimal expense associated with a simple DIY projection TV unit, and the shear simplicity involved in a basic design; no disassembling of the TV set is required.
When originally launched on the internet, most project plans were selling for around $15 to $30.
Despite the difference in pricing between different sellers, all plans were basically the same. Some of the more expensive designs would include a cheap inexpensive lens sheet to use with the DIY projection TV unit. However, today, these plans are readily available free on the Internet.
In its most basic form, a simple DIY front projection television is based on a CRT – Fresnel lens set-up. An LCD monitor could be used as a replacement to a CRT TV. These units would not cost more than forty dollars to build (excluding the TV or LCD monitor), but do not expect some big screen miracle here with these simple DIY setups!
Picture quality is tolerable when viewed in total darkness, but it is not as good as some articles might seem to imply, especially as the projected image size increases.
It is possible to build a more capable DIY Projection TV unit based on an LCD panel as the image source and an alternative light source.
LCD-based DIY TV projectors are much closer to the ‘real’ video projector in terms of image brightness and picture quality. Typical cost various from around $200 to $300 – depending on whether you will source used parts or not. However, at such an expense, the whole concept of building a DIY TV projector starts to be questionable.
You see, with present-day pricing, it is possible to get a brand new SVGA projector with a resolution of 800 pixels by 600 pixels – enough to support full DVD resolution – for less than $350! A case in point is the Epson VS210 SVGA Video Projector featured above which at present is selling on amazon for under $320.
Where is the Catch?
In reality, there is no catch in that these DIY units really ‘work’. But do not expect the projected picture quality to be anything close to that obtained from an off-the shelf LCD or DLP projector – even if the latter costs just a few hundred dollars as in the case of the Epson VS210 featured above. In particular, picture quality of the basic CRT-Fresnel lens DIY projector design is far from acceptable – with poor image sharpness and a relatively dim image.
In other words, do not believe all that the adverts seem to imply, in particular with respect to projected image brightness and attained image size!
To learn more about DIY projection TV principles, check our ‘Build a Projection TV‘ article. It presents the operational principles behind a DIY projection TV set-up; it also highlights the limitations involved, and suggests possible design improvements.
DIY Projection TV Design Sources
If you have gone through our ‘Build a Projection TV‘ article, you are fully aware that it is possible to build a functional DIY Projection Television set-up – within the limitations highlighted in our article – through two main design approaches:
– CRT-TV Fresnel lens set-up
– LCD-panel video projector
While there is nothing extra-ordinary behind the operation of a DIY projection TV, yet the main difficulty is to arrive at a most effective design to suit your needs. Experimentation is essential until you arrive at a functional projector design.
Rather than beginning from scratch, our recommendation is to make use of a proven design and then modify it – should there be the need – to suit your requirements. This will give you a good functional starting point while reducing your trial and error efforts significantly.
CRT-TV Fresnel lens Set-Up
There are several sources on the Internet for DIY video projection plans; interesting websites offering FREE plans based on a CRT TV – Fresnel lens design include www.bigscreentv.20m.com and http://fresnel.tk. Apart from a few insignificant differences, both sites present the same basic design approach and give you enough information to help you get started.
All that you require is nothing more than some thick Cardboard, PVC glue, black paint, duct tape, and an inexpensive plastic type Fresnel lens. We say inexpensive since it is possible to get a suitable lens for less than $2 at 3Dlens.com, eBay, and the like.
Our advice at this point is: Do not pay for what is available free. At one point, DIY projection TV plans were selling for anything between $15 to $20 dollars and even more!
LCD Video Projector Design
If you want to build a ‘real’ video projector, then an LCD based projection set-up is the way to go. However it all depends on the effort, both in terms of time and money that you want to invest in your DIY projector.
A suitable online source used to be LumenLab.com; but these are no longer providing the kit of parts for their DIY LCD projector; however, you can still find a summary of the available LCD projector plan by Lumen Lab here. More information on designing your own LCD projector is also available at www.audiovisualizers.com.
Note however that: An LCD based DIY projector requires a lot more effort to build than the simple Fresnel lens DIY projection TV. The overall project would take at least a few days to complete in comparison to the few hours required for the CRT based design. In addition, at the present video projector prices, building your own LCD projector would not result in some big savings but… it will surely result in big fun, apart from ending up with an SVGA (800×600 pixels) or XGA (1024×768 pixels) resolution DIY LCD video projector to enjoy your favorite DVD movies on a big screen.
Keep in mind the limitations highlighted in our discussion on this subject in our article Build a Projection TV.
These project plans are capable of producing modest big screen projections in a rather inexpensive manner. As such, a DIY video projection unit can serve as a possible big screen solution. Yet this big image projection is achieved at the expense of picture quality and significantly reduced image brightness.
And even though DIY LCD projection units can deliver a relatively bright image, these units can never match the image quality resulting from even the least expensive off-the-shelf video projectors available at major electronic stores.
In other words, NO matter what the information accompanying these DIY projection TV plans say, there is no substitute to a good quality video projector. Have fun & Good Luck!