I’ve barely had enough time after the spectacular Maker Faire to follow up on a request from Peter at CDM for more info on the screen I brought to the Chips + fish + music event in the city.
So, some history… Last year I got the crazy idea to build a projector from scratch, using an LCD screen and a 400 watt bulb. This isn’t really anything new or innovative, I used the tried and proven designs from Lumen Lab to achieve the results I had originally planned for. After the projector was built, I needed a screen to project onto. I’d already spent waaaay too much money on the project as a whole, so I needed a screen solution that would be:
- cheap cheap cheap to build
- easy to locate materials, or reuse stuff I already had
- free standing and structurally stable
- knock-down construction so I could assemble and disassemble it as my needs required.
- big when assembled
- compact when disassembled
- reusable for other purposes (more on this later)
So, with these goals in mind, here’s the solution I came up with:
materials and approximate costs:
- four “2×2″ studs, these are about 8 feet long, and cost about $2 each.
- four shelf brackets for the feet, 2 on each side. This cost can very widely, but maybe call it $4 each. This is even debatable.. you could just just whatever 90 degree brackets you have lying around. Or just run 2 or 3 screws into the bottom on the side legs into the feet and skip the brackets altogether. I ended up using two shelf brackets and two 90 degree steel brackets.
- length of PVC pipe. It’s cheap, easy to work with, and light.. sort of. – $8ish
- a little bit of hardboard for the u shaped holding things for the PVC – $free – $5 for a quarter sheet
- Various woodscrews, 8-32 machine screws, washers, and wingnuts, maybe $5 total in hardware
- a canvas tarp. I got mine from home depot along with the rest of the materials, and it has a nasty sewn seam across the middle of it. Not ideal, but again, I’d spent a bunch on everything else, so I decided I could live with a seam in my canvas screen. $10-ish
- finally, I used acrylic gesso on the tarp for two reasons. One is to fill the small gaps in the woven fabric, and two was to make the natural tan canvas closer to a white color. You could go completely bonkers on finding the right combination of primer, base coat, and reflective additives to cover your screen.. I just went with gesso. I had a bucket of it sitting right in my garage already. $optional
These construction details are more intended to be a guide than strict instructions. In fact the only major things I remember about the design decisions I made were that I’d have it be 6 feet tall, which would leave me a 2 foot long foot from an 8 foot tall 2″x2″ board. Also, I decided that I’d make the crossbar widths as big as I could to get the biggest 16:9 ration screen out of the 2x2x8 boards. So, if I have a 4 foot tall side from the top to the cross bar, that puts my width at like 7 feet 2 inches or something like that. Oh well. You get the idea. 16:9 good.
I had an extra length of PVC with a little room to spare, so I came up with the u shaped brackets to hold onto the PVC pipe off the back side of the top. It works really well, but you could probably achieve the same results with a couple of cloth straps looped and screwed into the top of the side pieces… in fact, I may end up changing it to that kind of system so that I don’t have to worry about the special shapes I cut out of hardboard breaking in transit to or from a gig. I just grabbed the edge of the tarp and screwed it into the PVC pipe with some short self tapping screws. Doesn’t have to be insanely secure, just enough to make sure it doesn’t rip apart and fall off the frame.
Lastly, I decided that I’d so with half-lap construction and use 8-32 bolts, washers, and wingnuts so that I could assemble and disassemble the frame easily and quickly. It’s all very cheap hardware, again, stuff I already had lying around. There’s very little on this design that’s “hardcoded” together, so it does break down to a small, if long, space.
Here are some more photos:
This is a detail photo of the foot construction:
Half lap joinery, at the crossbar:
8-32 bolts, big washers, and wingnuts on one of the top corners:
Here’s the canvas rolled up on the PVC and sitting in the u-shaped cradle brackets I made for this purpose:
Here it is, torn down and strapped together with some cloth straps I sewed together and used with some quick-disconnect clips. It’s leaning up against my garage door, so you may identify some of the door’s anatomical things in the photo…
and finally, here’s a rendered image of what it looks approximately like from the front when you have the screen extended to near the floor in “4:3-ish mode”… 16:9 mode can be achieved by only extending the canvas down to the crossbar.
And of course since I’m showing you 3d renders from Sketchup, you can grab the models from the 3d warehouse:
Exploded construction view and assembled view.
So far I’ve used the screen a lot at home in my garage, and taken it to a few gigs, and it’s done very well. Hopefully the design will inspire you to make a version to suit your needs. 
Let me know if you found this useful.
Technorati Tags: diy, LCD, make, maker faire 2007, makerfaire, makerfaire2007, projector, screen, sketchup, stevecooley
