Sunday, April 27, 2008

Amazing Weekend of Making Stuff with Friends

Thanks friends! You guys were amazing this weekend! Dan's plans for the solar reflector stand came to fruition; Jess found an amazing way to etch the acrylic; Shay designed the most perfect display for the booth at the Maker Faire; and Jill gathered supplies, sawed some bolts, and browned some amazing brats.

On Saturday, Dan and I got together at our friend Alice's place in Berkeley. We got to cutting some wood, drilling some holes and putting the stand together. Here's Saturday's video (1:44):

Sunday was kinda crazy because a guy from Current TV (Al Gore's television station based on user-generated content) came over to see the progress. Something that was cool: we lit the camera guy's cigarette from the solar collector. Then while the Current guy was wrapping up, the photographer from the San Francisco Chronicle dropped by. I think she got some good shots. A few of us capped off the day with some cheesy brats, grilled corn on the cob, and s'mores. Yum! (Sunday's video is coming.)

There's still plenty to do before the fair. On the reflector and stand side, I still need to mount the mirror and affix the fiber to the dish. I have some ideas and parts for this, it's just a matter of doing. Also, Dan's put a ton of work into the stand. This week, I'm going to try to pick up where we left off on Sunday and install the bearing so the dish can tilt to the sky smoothly and in style. Also, after Jess finishes etching the acrylic, I'll need to try to connect it to the fiber. In early tests with the fiber from the ACCRC, it looks like I need to make sure that the ends are flush with the pane. That could be tricky--or at least take some time and precision.

Then there's the display at the fair. We have a PVC-based frame for box that I'll cover with black fabric. I need to buy the fabric and make the curtains. I also need to work a little on the posters. I'm going to have one explaining the math behind parabolas and the physics of optical fibers. Also, information on solar collectors in general. Cool stuff!

Saturday, April 19, 2008

The Mount

I've been thinking a lot about the mirror mount lately. I have the parabolic reflector from Edmund Scientific (the 2-foot diameter dish). But I need to figure out a way to mount the mirror so that I can direct light from the focal point of the dish to the bundle of optical fiber in the center.

Enter: Edmund Optics (who is this Edmund guy, anyway?). I poked around this site for a while to look at optical mounts and I think I found one that I can emulate somewhat easily. It's essentially a ring with three screws (see picture below). You put the lens or mirror in the center and tighten the screws to secure it. I figure that I can take a lid to a jar and drill some holes for the three screws.

Once that's complete, the question still remains: how the hell do I secure the lens+mount to the dish in the right spot? Well, I've been thinking about this problem, and I think I have a decent solution. But let me back up. I have a rubber stopper that I'm putting in the hole in the reflector. I'm going to drill a hole in this stopper, about the size of the fiber, and shove the fiber through it. Okay, so that'll keep the fiber somewhat secure for testing purposes. Then I was thinking that I'd affix some large-gage wires (clothes hanger size or larger) to the stopper, pointing straight up. If I drill three or four more holes in the lens mount, then I can slide it right onto the wires. With this set up, I should be able to adjust the position of the mirror in a number of different axis, which is good, because I think putting this at the focal point and directing light onto the fiber bundle in the most efficient way is going to be a chore.

Sunday, April 13, 2008

Hitting the Fiber Jackpot

Best weekend ever (for light pipe building): I went to the ACCRC where James, the guy who runs the place, had 250 feet of fiber, dumped at his warehouse from a trade show. It was previously used to transmit optical light, not infrared telecom light, which makes it ideal for a fiber light pipe. He gave it to me. Amazing. The thing is, in order to get enough fiber, I was looking at spending more than $250 at vendors I found online. This dramatically reduces the project cost and puts discarded fiber to good use.

The other amazing thing that made this weekend great was that I got together with my friend Dan, who will be joining me at the fair. He had drawn up some sketches of a stand for the dish. This was going to be my biggest challenge because I'm not too experienced with bandsaws, routers, bearings and motors. Lucky for me, Dan loves this stuff. His design gives the dish motion in two axes. Also, he has a plan to use a motor and some disembodied wheels from a remote control car so that we can move the dish remotely. This'll be awesome for the display at the fair.