Geek Dad: Awesomely Geeky Projects and Activities for Dads and Kids to Share (18 page)

For all the game scenarios above, if you use the Velcro idea above, allow time-outs where plates/structures can be swapped out to rebuild a car mid-battle.

AND A NOTE ABOUT CLEANUP:
One potential time waster with this project is having to clean up all the bricks between battles. There is an easy way around this problem. If you’re like most GeekDads, one key feature of your workshop is a Shop-Vac. Make sure it’s clean and empty at the start, and then just vacuum up all the cast-off pieces between battles, and dump them back in the construction pool when it’s time to build some more. Easy!

Okay, GeekDads and Kids—time for some vehicular carnage!

I
n the last couple of years, there has been a spate of stories about enterprising students and other private citizens building and sending amazing balloons, with cameras and other instruments attached to them, miles into the sky. MIT student Oliver Yeh did it with $150 worth of materials (including a secondhand camera and a Styrofoam cooler) in September 2009. These packages then return with incredible pictures, providing yet more corroboration of the curvature and beauty of our planet. Such projects have to overcome some interesting technical challenges, such as GPS tracking and the necessity to keep equipment working in very cold, low-pressure conditions. Really, they are a kind of UAV (Unmanned Aerial Vehicle).

While launching a balloon several miles into the sky is a tremendously exciting project, it is not the kind of thing you can throw together with your kid over a weekend. This project, though, is designed to help you have the same kind of fun at lower altitudes and for significantly less expense (of both money and time).

A little research on the Internet tells us that, based on the lifting capacity of helium, a group of balloons with a volume equivalent to a 4-foot-diameter sphere (around 12.5 cubic feet) should be able to lift about one pound of payload. So, to pull this project off, we have to keep the mass of our entire build under that limit and/or fudge the number of balloons (and thus total helium volume) so we can get a little extra lift. If we can inflate the “normal” balloon that comes with the kind of party kit you can buy anywhere to about one inch in diameter, then we’ll need about 16 balloons to get the kind of lift we want (each one-foot balloon would hold about 0.75 cubic feet of helium).

The overall design concept is this: Build a “column” of helium-inflated balloons, not unlike what you see at fancy parties, hook a camera to it, and let ’em fly while keeping them tethered to the ground (you) with kite string. The camera itself needs to be set securely into some kind of padded open-face enclosure so that it won’t be jarred too severely upon a rough landing (though we’re hoping for a very controlled descent). And that enclosure has to be connected easily to the kite string so that the camera doesn’t go flying a lot farther than you want it to.

The balloon method I suggest using for this project is not the only way possible, of course. A kite could work, and could potentially be somewhat less expensive and require purchasing fewer materials. However, most inexpensive kites are not as inherently stable as balloons. Balloons want to go up and stay up, and it’s you keeping them from doing so, whereas a kite, unless it has caught the wind just right, wants to come down and crash into the ground. And because for a kite to work properly, it must be a windy day, it won’t keep an attached video camera as steady as will a placid bundle of balloons on a windless day (and please, let me stress that you want to do this project on as windless a day as possible).

It is at this point that the pro-kite community will argue that there are kites that can be very stable when aloft. This I do not contend. However, I’ll point out that such kites will cost at least as much as the helium we’re using, so we’ll say touché, and move on.

A Flip digital camera weighs just slightly more than five ounces, making it an excellent choice for the technical package. Plus, a lot of geeks already have one, so it may not be an extra expense for you for this project. If you have a different camcorder, check the weight. Anything much more sophisticated than the flash memory-based models available right now (Flip, Kodak, and similar) will likely weigh too much.

Of course, sending a valuable piece of technology up into the sky, tied to a bunch of balloons, may get you an odd look from your spouse, but we have no good suggestions here to help you with that, other than telling her or him it’s for science!

STEP 1:
Because you’ll want to get your video camera back, you’ll need to tether your craft, and even if the kite community is still smarting from the logical thrashing I just gave them, I do suggest using kite string since, really, it’s made for this sort of thing. One reference I found online cites a weight-to-length ratio for kite string as 1 pound for 8,700 feet of string. If we restrict ourselves to a commonly available 500-foot line, that adds only 0.9 ounce to the package when it reaches full height.

 

STEP 2:
Next, we need a cockpit for your camera (no sniggering). My choice was a piece of Styrofoam I picked up at my local hobby shop. It was actually purposed for carving out mountains for model train landscapes, but the size and strength were right to work with, and the density was great for cutting with a chop saw. Foam packing material that comes in standard toy or equipment packaging may work as well, though it’s usually less dense and thus harder to cut cleanly. On the other hand, that means it’ll weigh less, so there is a fair trade-off.

 

STEP 3:
We don’t need the piece of Styrofoam to be huge, so just cut it down with a chop saw or serrated knife to about double the size of the camera itself. Then trace the camera’s outline on one side (with a little fat), and use a mat knife to trim out a cavity into which the camera can be set.

 

STEP 4:
To attach the anchor points to the camera, get your duct tape ready. Lay two zip ties (unzipped) laterally across the top of the foam block and then tack them down with a small square of tape. Do the same on the bottom. If you are an engineer like me, and want to feel you’re accounting for stress lines and such, have each zip tie in a pair oriented in opposite directions so that the points and heads are reversed. This is probably completely unnecessary, but don’t tell your kids that; rather, impress upon them the vital importance of this key design factor in ensuring stability and structural integrity. If they ask “Why?” just shake your head and tell them, “Someday, you’ll understand.”

 

STEP 5:
With the zip ties tacked on at the top and bottom, take the duct tape and, starting from the back side of your package, make two complete passes down, under, up, and over, pressing the tape into the camera cavity each time you go around. Finish the tape on the back where you started. Now repeat this, going horizontally around the package, from back, around the front, to the back, and around again, pressing the tape into the cavity each time. Your finished product should look something like this:
With all this done, you’re about ready to fly. All you need is your anti-gravity technology!

To tie the balloons, you can use the classic thin iridescent ribbon that comes with many party tanks of helium and balloons. While it’s cheap stuff, it is very lightweight and has, as anyone who has tried to open a present by pulling the ribbon apart knows, tremendous tensile strength!