the aj blog

An application I created to control a USB7 from a computer's serial port.

The USB7

Quite a while ago, I discovered the USB7. It wasn’t until recently I actually thought I would have a use for it if I were to buy it. I was working on a website project due at midnight on a particular day. I was thinking how awesome it would be if I could have a bunch of LED 7-segment displays counting down the days, then hours, then minutes, then seconds, and finally hundredths of seconds. That was when I remembered it, the USB7. The USB7 is a relatively inexpensive, usb-controlled kit with six 7-segment displays. I haven’t seen many popular projects for it, though, so what does one do when there’s a need for something but it doesn’t exist? You make it! I bought a kit online, so it’ll arrive sometime later.

The Programming

Turning to Visual Studio Express 2008 and my brain’s Visual Basic abilities, I created this super-simple application that continually updates the display with the time remaining, fitting as much data as possible. For example, it can show up to 99 days, 24 hours, and 60 minutes when there’s more than 24 hours left. When there’s less than that, but still more than an hour, it’ll display a 2-digit hour code, a 2-digit minute number, and a 2-digit second number. Once you’re down to minutes, it shows minutes, seconds, and hundredths of seconds. Down to seconds, it’ll drop the minutes. Finally, once the timer’s up, it plays a crazy alarm sound and flashes constant zeroes all across the display. Now just to wait until it arrives!

A common household drawer module combined with a label maker makes for a very organized parts system.

Organization is crucial in almost every aspect of life. One of these aspects, as a tinkerer, is being able to find parts easily. I must admit that my floor where I work on projects is littered with failed, partial, or abandoned experiments. For example, one of the things I lie among is a pencil sharpener with four wires coming out to an ominous control box. I often lose parts, only to find them months after the intended project is over. So, I turned to a drawer thingy like in the photo, and just labeled all the drawers accordingly. I have everything from “scavenged little things”, “screws”, and “alchohol swabs” to “chips”, “relays”, and “piezos”. Unless the drawers get really full, they all pull out easily and I can see what’s inside before that even. I want an LED for my Arduino, I pop open the top left drawer and fish around for a good one. Being my geeky self, I get a similar happiness as if each LED was a candy and I was a kid with some spare change to spend. This system has paid its self off in the time saved not looking everywhere and digging everything up in a search.

A plain copper board toner transferred, touched up with marker and labeled.

Toner Transfer

As part of the process for home printed circuit board etching, you need to somehow get a resist where you want there to be copper. After the transfer, you can then apply any of many different etching chemicals which then dissolve the unprotected metal. In my opinion, this step, good toner transfer, is the hardest and biggest roadblock to anyone trying to make a quick board. The concept is relatively simple, iron a laser printed piece of paper onto the copper, fusing the plastic toner to the copper. Commercial products are sold that achieve this much easier, but who wants to have to spend money, pay shipping, then wait for it to arrive? So, trying as many different tutorials I could find on the Internet, I set out to meld plastic to metal. I used a cheap old LaserJet 5P for this purpose, and printed a schematic out on magazine paper first. I ironed it on, and it partially held, as visible in the lower left corner of the photo. I then used Office Depot Presentation Paper to try and get a better stick. It was a bit better, as seen in the upper right. I also tried different combinations of scrubbing preparations and such on the back. None fully worked. I got a bubble tank ready, a bubbler, all the chemicals, and even a glove box, and the only conclusion I can come to is this: toner transfer is no fun!

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.

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.

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!

Google's chats are stored within the user's Gmail account.

Concept

One day, it was like any other day. Gmail chatting with a friend. Not doing much. Then I started to think, what if I could see a ratio of how much I talk versus the person on the other end? Then I wondered what it would take to script something up to do precisely that. I was planning to use Visual Basic, but that would be Windows bound. Then I wanted to use Java. But then it wouldn’t work because I learn Java, forget it, learn it, forget it. I’m in my forgotten phase. I even considered Lua, the uber language. Then it struck me. PHP! The best hypertext preprocessor! Then the whole web-ter-net could enjoy it! I messed with PHP for a bit before realizing that Wordpress doesn’t like to play well with it. I guess it’s good for security.

Try It!

I really wish I could tell you to start using it today but I haven’t actually wrote it yet. I’m horrible at my Javascript, so it might take longer than one would expect. But, I promise, something will come of this.

Interpreting the Facts

Although not nearly as good as a psychiatrist or anything professional, you probably could see quite a bit into people’s personalities. If, for every word you say, your friend says five, you could tell they likely talk a lot. Or vise-versa. A small tool. Multiple possibilites. Coming soon to theajblog.

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!

My First Dorodango

Mud Balls - Awesome!

After seeing a dorodango featured on Mythbusters (End With a Bang, November 12, 2008), I became quite intrigued by the concept. It fascinated me that using nothing more than average dirt, one could produce something of such beauty and shininess. Shortly later, I came across this site which gave me some hints and eventually led me to this site.

The Quest

I went out and dug up a bag of dirt (it’s winter, the ground is hard.) After letting it dry out for a while, I began with my core, which took me about an hour. I put it in a bag to cure overnight.

The Next Day

I slept in late. Waking up around 10, I began the final capsule and polishing process. Around an hour and a bunch of rubbing later, I took the photo featured above. Success!

Reflections

There were many things I would do differently next time. I’ll describe them so that hopefully, if anybody takes up this wonderful and calming hobby, they will know. The first and probably biggest issue with what I did was the quality of dirt. You should let it dry out, sift it, and get out all the rocks. otherwise, you get something like mine, with little bits of hard stones sticking out. Second of all, don’t get your dirt on anything white. Couches, towels, rugs, shirts; they’ll never be the same. Third, make a bigger ball. Although the photo has little scale, the ball is actually about the size of a golf ball. It was quicker, but smaller. Oh, and don’t use contaminated soil, it made mine smell nasty.

So, take a couple hours with a pile of dirt, make a dorodango, and have a happy soon-to-be new year!

Photo, and other works in this post , are under a Creative Commons BY-NC-SA license.