I once built a DIY beamer out of an old overhead projector and an old 1024x768 pixel TFT screen. Basically, I removed the backlight of the screen, used the raw

I once built a DIY beamer out of an old overhead projector and an old 1024x768 pixel TFT screen. Basically, I removed the backlight of the screen, used the raw screen instead of the glass table, and put an extremely bright metal halide lamp and several fans into the projector. This was 20 years ago when beamers where quite expensive, and this one cost around 60 EUR. It worked very well, the picture quality was amazing, and I used it for some years. You could also heat an entire room with it!