I’m past the point of no return now!

I was catching up on my multitouch forum yesterday and decided to poke around on the Internet for components. One of the major pieces to the puzzle is the projector or LCD monitor, and thanks to some good advice from some forum-goers I decided that I would end up going the projector route.

I decided, on a whim, to see what projectors could be found on the Ebay market. Apparently, yesterday was my lucky day. I ended up winning this baby for $509.

You will see from the auction listing that this projector has a short-throw lens, which is desirable for a multitouch table. A short-throw lens means that I can get a reasonably sized image (30″ diagonal) from its minimum throw distance of 2.3 feet. The reason this projector was such a good buy is because a short-throw lens appears to up the value of the projector into the $900-$1800 price range, which means I got a steal! 🙂

A few forum members have piped up against the practice of mounting the projector facing straight up, since the heat generated by the projector would gravitate toward the lens and might run the risk of warping it. It is being recommended that I use a first surface mirror to reflect the image once into my projection surface, and that would allow me to mount the projector with the lens down, or perhaps horizontally (as nature intended).

A first surface mirror is one where the reflective surface is on the front-most layer that the light hits. Most mirrors you see are second surface mirrors that have the reflective surface behind glass, and that can cause a secondary ghosted image if the light source is bright (like, say, from a projector).

Front surface mirrors are usually pricey, but apparently you can make one using a $4 mirror from Wal-Mart and a $5 can of aircraft stripper. That sounds like fun, probably because of “aircraft stripper” in there so I’ll probably at least entertain that notion.