the aj blog

My pizza box laptop case with vacuum formed shell.

Not My Idea

This has been commercially done and covered. I merely made my own DIY version. Please don’t sue me. Glad that’s over.

Why?

Very few thieves are willing to break into a car to steal a pizza. But who knows whether there’s actually pizza in that box? Who knows it isn’t a laptop, say? The answer is, “if done right, there is no way to tell.” I often take trips to NYC with my laptop, and as with any big city, I have to hide it. Beneath a seat, coat, blanket, anything. I will no longer have said problem! This very quick design would look a lot nicer with some paint, but I’m worried about dissolving the awesome urethane foam I used.

Authentic Pizza Box

To increase realism, and the chances it will be accepted as nothing more than pizza, I went to a local pizza shop. I asked the guy for two slices of pizza, and a separate box for a project, to which he happily obliged.

Vaccum Formed Shell

To make my laptop fit perfectly, I turned to vacuum forming. Unwilling to spend mucho money on a professional former, I settled for a “kitchen floor” version, as can be found in MAKE. It’s called “kitchen floor” as you basically are stuck there, using the oven as a heat source. My first attempt catastrophically failed, sticking to the oven rack. Messy. The second try, I successfully got it out in time, then right on top of my laptop. Vacuum on. Wait 10 seconds. Done. As a precaution I had put greased foil on top of any stickers just to be safe. I trimmed this mold down until it fit the box in the way I wanted. I also drilled out a hole so I can discretely put a power jack in and charge without giving anything away. This got affixed to the box where I wanted it with lots and lots of Great Stuff (expanding sticky urethane spray foam).

Cord Portholes

To permit simple and secretive cords to leave the box, I cut a few three-sided rectangles out of the bottom (basically leaving them hinged). I extended the already existent ventilation slots for the same purpose.

Padding

I looked around for the quickest soft thing I had. It was a strange pile fuzzy fabric, an unattractive greenish. Almost half a bottle of contact cement later, bottom of box lid and fuzz were one. This pads the laptop in case the strap is not used or fails. It also probably makes it hotter (not good).

Strap

Reuse is the first of the 3 R’s. I had a laptop bag that after years of service was covered in holes. It had a nice laptop strap. Best of all, it was free. A seam ripper made short work of the binding stitches, and the strap was free. I dug two little holes in the foam where I wanted to mount the strap and squirted some Gorilla Glue in. Put the strap in, duct tape temporarily in place, and more foam. I don’t know whether it was the glue or the foam which holds it in, but it’s stuck in there for good.

Conclusion

On the inside, it looks like junk. It’s screaming for black paint. Regardless, it actually ended up costing me nothing, having all the materials on hand. There is room in back of the laptop for any other small gadgets and a modern power brick. Finally, the real goal has been achieved, to build a case which no one will want to steal while containing something they would.

A vaccum forming disaster, now considered "art" and hanging from my bedroom ceiling.

The chair, rigged and ready for a tree and pulley.

What??

A bosun’s chair is a type of seat often used when someone has to be lifted up somewhere, like a high up mast on a boat. What I made is also effectively a bosun’s chair. It’s effectively a lawn chair turned bosun’s. Using climbing rope, some thinner rope, a bunch of webbing, 3 carabiners, a metal chair, and a ~$15 oscillante pulley from EMS, I managed to develop a device enabling you to hoist yourself into a tree. I specifically like my version because of the suspended lawn chair effect. It’s hard work, lifting your own weight, due to there only being the one pulley. I have to add more knots to actually make it practical too. But it sure was fun, dangling in the air, sitting in a chair (rhyme unintentional).

Warning

Test your chair with 1.5x your weight in sandbags before sitting in it. I am not responsible for any damage or injury caused by performing anything in this article. I wore a ski helmet/goggles for extra protection/coolness factor.

Setting it Up

First of all, you need to rig the chair. Using a knot who’s name I can’t remember, the one that tightens with force like all good knots and has a loop, get it so that each leg is on the rope. Tie them all together. You should now be able to lift the chair with one hand, holding it by the long rope extending upwards. Then, make a kind of seat belt with some different rope, tied to one end of the chair with loops to hook into a carabiner on the other side. To finish it off, tie a separate piece of rope to the main one closest to the chair, so it can be carabiner’d to a loop on the other side of the pulley to lock you in place. Then, get the pulley into the tree. The particular one I used I believe had a safe working load of ~2 kn (~500 lbs.) and a breaking load of 16 kn (~4 tons). I’d only be putting 200-something pounds up so that wasn’t a problem. Using the webbing, get the pulley on a carabiner on to an extending branch. Loop the rope through, then make lots of loop knots to climb up and clip into. There you have it! Hoist yourself up, enjoy the view, and don’t fall down.

My iPod goes to the amplifier, then is transmitted through a radio.

What’s Happening?

So, the way it’s working in the photograph is that music is going from my iPod, to the hacked amplifier, to the handsfree jack, which then transmits on FRS/GMRS frequencies. It can be heard with another two-way radio. Now, you may be thinking, “Why’d you just re-invent the FM transmitter!” Well, this doesn’t transmit on any traditional FM/AM radio frequencies. By utilizing two-way radios for communication, other people with radios you’re already using can hear! Or, play really weird music and annoy them! I prefer the latter.

How is This Done?

The particular gift card was the one that Best Buy sells, which features an iPod speaker on the back. The card comes off easily, with some clips. Take a bunch of screws out, and you expose the circuit board. All I did was desolder the speaker leads and solder on a mini-audio jack, like the ones found on cellphones and handsfree systems. I soldered the positive speaker lead to the microphone section, as visible from pinouts.ru, and then soldered the negative lead to ground. Holding down “talk” with everything on blares music on the selected channel. A tad quiet and finicky, but better than without amplification. Awesome!

Salt Dough Landforms

Who Needs CAD?

Who does need CAD for simple projects? Who can afford those things? Answer is not many beginning hobbyists. Especially when you’ve got the power of one of the best tangible prototyping interfaces on your hands available today! It is…salt dough!

What’s Salt Dough?

Salt dough is an edible but nasty-tasting dough usable for all sorts of applications. For example, in the case seen above, you can prototype imaginary land forms. It dries in a matter of hours for small pieces, and a matter of a couple days for thicker things. It’s simple, and can be made with off-the-shelf kitchen supplies easily. Just form it into whatever you wish to make it look like, be it anything from a project enclosure to a prototype of a new type of jewelry. Let it dry on a cookie sheet. When it’s done, you could vacuum form it into something usable, carefully hollow it out and make something, or just let it be as is. Choosing the last step, you can proceed to painting. Most general purpose paints should work, probably not oil paints or whatever. Let it dry. Finally, if you really feel it needs a protective coat, dunk it into a little puddle of Elmer’s glue and put it onto a piece of paper or something. After about 10 minute, take a brush and even out the coat, making sure it doesn’t collect into low parts. The best quick, cheap, “slow prototyping” method!

Recipe

Quite simple, here it is:

- 1 cup of salt
- 2 cups of flour
- 3/4 to 1 cup of lukewarm water, depending on humidity. Trial and error.

Add the salt to the flour in a bowl and mix with your hands. Just try not to get it into cuts, as it stings from the salt. Add water until the whole mixture is mixed up. Knead on something easy to clean. Can be stored for about a month in a sealed container. Then it starts to rot and get stinky. Not wanted. Throw away upon rotting, please.

"Project SteaDIY"

Yay!

I actually had some time and got around to building the Merlin clone. I think I might nickname the project “Project SteaDIY”. My first and foremost problem was the pipe I had ordered. I had had no idea what wall size to order, so I just went with 1/8″. Big mistake. That stuff is like, the type goons carry around to whack people with. Not the kind I can bend in a wooden form. So, I downgraded. Going out to the local hardware store, for about $2 I purchased somthing like 8 feet of thin wall steel conduit. It’s steel, so it’s heavier. But it was bendable. I used a 4.5 inch radius plywood form to bend the semicircle, with a lever type mechanism as described here. It worked, with no kinks either! I crimped something like the last 2 inches in a vice, making it flat.

Attaching Everything

Although I certainly did goof quite a bit when it came to the drilling measurements, resulting in off holes, it all worked out in the end. At Wal-Mart I found some Stanley Line Levels which, after beating into submission, I was able to bolt on. I had the balance bolts ready for a while, also making it easy to bolt. As for the handle, I don’t have anything special that works yet. I tried a kind of gimbal that I had made, more a piece of art than anything else, which broke under the strain of the rig. So, sacrificing stability for simplicity, I merely chopped up something that would work for a handle and bolted it on too. I really need to get a better handle-rig mount that will allow more handle jiggles and less footage jiggles.

The Price?

Amazingly, I think it was under $50 for everything. The most expensive was the plate, which was special order 6061 alloy 1/8″ aluminum, at about $10 including shipping or something like that. This is, of course, not including a camera.

The Synopsis?

I’m not done yet. On my to-do list: better weight balancing, and a better handle mount. The rest works fine, all good.

Shipment Arrived!

Yes!

Finally, the climax of all that shipment tracking has come! Delivery! My OnlineMetals aluminum arrived today. The plate looks great (no rhyme intended) and although the pipe is a tad thicker than imagined, it’ll work fine most likely. Sadly, I can’t get to my workbench, tools, or anything at the moment, so any actual work will have to wait for about a week. I can merely think about what I’ll do with the pipe and plate before then. Although, I do have some ideas in mind…

Drill Pattern

For the plate, there will be three or so holes right in the center, all aligned. Or perhaps a channel cut through for ultimate positioning? Anyways, my 1/4 coarse bolt will go through it, permitting me to mount a camera. This is the top of the thing. I will drill 2 holes, also aligned, on the ends of the plate, for my balance bolt system. I might even have to add weight on the other side to compensate for the weight added by them. I might drill other stuff, for things like a level or whatever.

Tubing Bend

I have found an instructable on how to bend tubing without it kinking and such. It looks prominent. I plan to make the form the next chance I have, hopefully it’ll work and the powers of the Internet would have succeeded! If I’m not too sleepy from my next experiment, that is. Oh, we’ll find out about that later…

UIP (Unrelated Interesting Photography)

What’s That Picture?

Since this article doesn’t particularly have a very tangible topic, I chose to fill in the blank space with a shot of me holding a freshly toner-transferred PCB.

OnlineMetals

If you even glanced at my steadicam draft, you’d probably see it involved some tubing and other various metal parts. Finding these in a local store and having them meet your specifications is pretty hard, so I turned to the Internet. Being an avid subscriber and reader of MAKE, I started searching through their blog. I found out that, through a partnership with a certain metals company, they were offering a 5% discount. The particular company was OnlineMetals.com. Although I don’t really have any experience in any other metal sources, their service was really good. You can order any of their various metals online, and they arrive at your door in a week or two via UPS. A cool feature is the ability to “custom cut” your plate, tubing, or pipe. There is a relatively small fee for the cutting, but it’s worth it. Awesome!

What Did I Order?

Anyways, for the main part of my Merlin clone I needed a length of arced aluminum tubing. I settled on 2 feet of 3/4″ OD 6061 aluminum alloy tubing and a 5″ by 6″ 1/8″ 5052 alloy aluminum sheet. The sheet is for holding the camera on top, and the tubing is the main bones of the whole thing.

How’s it Going to Look?

The balance bolts get mounted underneath the plate, upside-down from the picture previously featured. I might paint the tubing black, merely for cosmetic reasons. Scheduled to arrive on 2/10, this guarantees to be awesome!

My creation for my stabilizer project, permitting easy adjustable side to side balance.

The Balance Bolt

My own creation. My very own. I think it even cost under 10 dollars to make two. What I needed was a way to adjust balance left to right and side to side. If you looked carefully, you would see I mentioned this type of device in my original sketch.

Creating It

The design is rather simple.  For one you need two L-brackets, one 1/4 inch coarse bolt, and a bunch of 1/4 inch nuts. The picture had 11. Depending on the size of the holes in the l-bracket, it may be necessary to drill them out to 1/4. Take one, and thread the bolt through the hole. Put a nut on and use a wrench to tighten it. Put some more nuts on, like 8, and put the second L-bracket on. Tighten the nut nearest the second bracket to almost secure it, and put a nut on the end to lock it in place. Tighten with wrench. Yay! You’re done! Actually, you should’ve mounted the brackets before putting them on the bolt.

Using It

Nothing could be simpler. By adjusting the nuts to either side, you can change the balance. You could put washers on if you need more weight, and sandwich them between the nuts. Run with it. Make it work for you!

Steadicam Sketch

The Steadicam

Ah, the Steadicam. A miracle for the video industry. A horror for the no-budget hobbyist. Sure, this has probably been done before, but I have found (almost) nothing as beautiful as the original versions, such as those made by Tiffen. Who says that making it pretty has to be expensive?

Why?

The stability of professional stabilizers is unmatched in either software or camera internal stabilizers. Who wouldn’t want something that works that good? Oh, and professional models do all kinds of crazy things with little motors, but balancing the weight is the best easy method of stabilization. So I decided to try and recreate one of the lower-end basic no-trick steadicam models.

How?

One day when I was bored, I sketched out a DIY version in my journal. You can click on the thumbnail for a bigger picture. I estimated the cost to be around $40. Around 20 in random assorted hardware (think washers, nuts, and bolts) and like 20 in essential structural components (think aluminum tubing and plate). There’s also a lot of other random junk on the scan, so take it with a grain of salt.

The Disclaimer

I have plans to perform this and produce a video or something on it. Since I have documented and published these rough plans, I retain the copyright until further notice. Please, if you do anything involving this article or its assets, provide attribution and a link. There will be more updates as I progress further. Thanks for cooperating!