Home Built Rear Projection Screen – $23

January 25th, 2010

I moved in to a new place this past summer and brought my moderately priced projector and cheap ($100) 100″ screen along with me. The problem is in the apartment’s layout there’s just no place to set up the screen that’s watchable. What we do have is a set of French doors between the living room and bedroom to work with. Rear projection screens (and even the material) is expensive and what’s worse I couldn’t find anything that would work well in the space — most were too big, all were to expensive for my current tastes/setup. A little bit of brainstorming, internet searching, and back of the napkin schematics later I had a plan.

I was going to build a simple frame and use wax paper as the screen material. The idea of using wax paper came from seeing a window display that utilized sheets of it (or something very similar) glued/tacked to the glass as a projection material. I didn’t have a 78″ diagonal piece of glass laying around and even if I had it would have been seriously heavy. Not that big a deal if it was going to be permanently mounted, but a bit of a problem if the plan was to only put it up when being used (since it would be in the middle of our apartment.) I figured that stretched tight enough the wax paper alone would do a decent job and tests of small pieces with the projector proved that out. The only kink in the plan was that one sheet wasn’t enough. It was letting too much light through and the image lacked saturation. Two sheets did the trick and looked great.

The next problem was dealing with the seams. The solution was to weave the two layers of wax paper. The woven sheets tightened things up a bit and the friction kept them in place so that once I lined up the edges of adjacent sheets they did a really good job of staying put. I wouldn’t say it’s perfect as you can see in the picture with the room lights on, but once their out and you’re watching the movie you hardly, if ever, notice them. By all means if you look for them you can see them, but as soon as you quit paying attention they all but disappear.

Parts List:

  • (3) 2″x2″x8′ pieces of wood – $15
  • (4) right angle metal brackets – $4
  • (1-2) rolls of white/bleached wax paper $4

If you have the wood working equipment to do properly joined corners you can probably skip out on the angle brackets (I don’t atm.) The wax paper was a little difficult to come by, not really sure why. I had to search around at several grocery stores to find one (Safeway at Church and Market) that did. The stuff exists for sale on the internet in heavier weights and in larger width rolls and if you can come up with the stuff at a good price you may end up with a slightly better screen, but as the pictures show the standard kitchen stuff works.

I won’t go through step-by-step detailed build instructions mainly b/c I didn’t take pictures to go along with them, but an overview follows. I started by cutting the boards with 45 degree ends to length. For my target of 78″ diagonal with a 16:9 ratio that worked out to roughly 68″x40″. The exact measurements aren’t critical, but the two long pieces and the two short pieces have to be exactly the same size as their counterparts. Once you’ve cut them to size you’ll need to drill pilot holes and screw the corners together, 2″x2″ stock will split easily so make sure you pre-drill the full depth with a bit as close to the size of your screw as you can, while still letting it get a grip.

Next, you’ll need a large flat clean surface for the weaving portion: tile, wood, concrete, etc. start by cutting all of the pieces for one direction to length. I started cutting the pieces that would run from top-to-bottom. I then lined them up loosely and then used painters/masking tape to tack them in to place on one side. Once that was done I wove the side-to-side pieces in to place and cut them to length. I then tacked them in to place on one end and started to tighten up all of the seams and alignments. At this point it should be clear that the reason I used masking tape was so that things could be adjusted without fighting a stickier tape and tearing the wax paper every time an adjustment was needed. Once I was pretty happy with the alignment of things I began working my way across the bottom tacking the loose ends of the wax paper strips in place and then continued up the final loose side until all of the wax paper was tacked in to place. After a few minor tweaks and adjustments I went around the perimeter of the frame using packing tape (much stronger, stickier, and longer lasting) to do a more permanent job.

A couple of hooks in the frame and a couple on the top of the door jam and we’re in business.

A full photo set with larger images can be found here

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“It’s one thing to be afraid of terrorism. But there’s no real reason to be afraid of terrorists”

November 18th, 2009

“It’s one thing to be afraid of terrorism. But there’s no real reason to be afraid of terrorists” – Daphne Eviatar

great quote from a decent article

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“When I take that oath of office, there will be kids all over this country who don’t really think that all paths are open to them, who will believe they can be anything they want to be, And I think the world will look at America a little differently.”

October 30th, 2009

“When I take that oath of office, there will be kids all over this country who don’t really think that all paths are open to them, who will believe they can be anything they want to be, And I think the world will look at America a little differently.” – Barack Obama

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Better dead than fed, PETA says

August 16th, 2009

The Center for Consumer Freedom, which represents the food industry, a frequent target of PETA campaigns, released data filed by PETA with the state of Virginia that shows PETA has killed more than 10,000 animals from 1998 to 2003. “In 2003, PETA euthanized over 85 percent of the animals it took in,” said a press release from the lobby, “finding adoptive homes for just 14 percent. By comparison, the Norfolk (Va.) SPCA found adoptive homes for 73 percent of its animals and Virginia Beach SPCA adopted out 66 percent.”

via Better dead than fed, PETA says.

An old article, but still interesting. While there may be explanitions, including PETA taking animals they feel are being inhumanely euthanized so that they can be put down in an acceptable manner, but the differences are still pretty stark.

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301 Redirects – Getting Old Feed URLs to Work With Wordpress

April 21st, 2009

If you have an established blog and have readers who subscribe to your feed you’ll likely loose them when you migrate to Wordpress and your RSS feed URL changes. Wordpress feed look like http://www.mysite.com/blog/feed/ if you’re blog is at http://www.mysite.com/blog/. My previous blog software’s RSS feed url looked like http://www.mysite.com/blog/?wl_mode=rss2. I didn’t have too many subscribers, but there were a few and I didn’t want to leave them hanging so I set about using a 301 permanent redirect to solve this problem.

Fixing this is pretty straightforward, just a couple of lines of code. For me this the following placed near the top of index.php does the trick.

if ($_GET['wl_mode'] == 'rss') {
        header("HTTP/1.1 301 Moved Permanently");
        header("Location: http://" . $_SERVER['SERVER_NAME'] .  "/blog/feed");
        exit();
}

It looks for the get parameter wl_mode to be ‘rss’. If wl_mode is defined and equal to ‘rss’ it sets two headers in the response and then exits. The first tells the client to redirect and that the redirect is permanent. The second gives the location to redirect to, the server name of the request, from the variable so that it matches whatever hostname the request was made to and the path of Wordpress’s RSS feed, ‘/feed’. The ‘/blog’ is where Wordpress is installed on my site, if your root is Wordpress you’d just have ‘/feed’.

What if your old url wasn’t wl_mode=rss. If it’s a different parameter or set of parameters you’d just swap them out. What if the old feed is not a parameter, but a URL/path? Something like the snippet below should be useful there.

if ($_SERVER['REQUEST_URI'] == '/blog/old/feed/path') {
        header("HTTP/1.1 301 Moved Permanently");
        header("Location: http://" . $_SERVER['SERVER_NAME'] .  "/blog/feed");
        exit();
}

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