2. Giant Wall Display, Continued

Really bright: Windows desktop projected onto the wall

We decided from the start that we wanted a high-resolution system offering XGA resolution (1024x768 pixels) as a minimum. In contrast, most eBay do-it-yourself systems are based on VGA (640x480) or SVGA resolutions (800x600). Who would settle for 300,000 or 480,000 pixels when you can have almost 800,000? A glance at the current price lists of electronics discounters shows that despite greatly reduced prices of late, you still have to shell out around $1,500 for a projector with XGA resolution. We thought $300 tops would carry the day with our own system. Added to the enormous savings is the fun of building something yourself, while taking advantage of numerous options for improving picture quality.

Components And Cost: TFT Screen And Overhead Projector

In principle, both store-bought and do-it-yourself projectors consist of a liquid crystal display backlit by a light source. An old or used flatscreen LCD is ideal for the display; these can be picked up for prices starting at around $100. An older 14" or 15" office-type TFT monitor that is due for replacement by a 17" or 19" model is well-suited to the task. There are also flatscreen monitors that have diminished backlighting or even none at all. These devices are ideal for use in constructing your projector. If you don't have a suitable used display, a $200 bargain from your local electronics discounter will do the trick.

Once you've settled on a screen, you can turn your attention to getting hold of an overhead projector. Used devices can be had for as little as $50. All in all, a homemade projector will set you back little more than $250, working on the assumption of XGA resolution, as we said before.