Ok, you probably can’t make the baby grand in this picture, and even the metronome is likely to be a serious DIY challenge — but you can definitely make a pretty accurate DIY scale, and you can do it cheaply and easily.
I needed an accurate scale for a science project and knocked this baby together (based on this design) using found parts. I was able to easily measure to centi-gram precision and with a little care, a scale like this could be tuned to measure to milligram precision.
Precision (the ability to discriminate between differences in mass) is largely a matter of careful construction — accuracy (the ability to weigh to an agreed upon standard) is another matter altogether, and it basically hinges on having an accurate reference. Fortunately, a great institution, born of Philly — the U.S. Mint — was wise enough to make Nickels and Pennies in rather convenient dimensions. It turns out that nickels are 5.000 grams and pennies are 2.500 grams — so you not only have sub-milligram accurate references of convenient size — you also have an easy way to cross-check your scale by using nickels to weigh pennies and vice-versa.
Details of DIY Scale
The zoomed in photo shows most of the essential elements of construction. Basically, I used a threaded 10-24 rod for the balance (10-32 would have been a better choice). I used a wall-board razor as my knife-edge pivot point. Two angle-brackets served as a hard, flat surface for the knife edge. A nickel with a hole in it and some thread served as a reference weight (I wound up with a whole array of perforated nickels and pennies). A wall-board T-square served to measure the distance from the pivot to the reference weight. I used an index card and a small mirror to make a sliding mirror in order to read the position of the weight w/o parallax error. The whole shootin’-match was held on a stand that was salvaged from a cheap drill-press. Measurements were performed by reading the distance between the movable weight and the pivot point, and entering that value in a Google Docs spreadsheet.
I definitely could have purchased a milligram scale for far less than this cost me in terms of spare time, but I learned a lot about scales in the process. Almost all of it was stuff that I knew “in principle” — but actually building the scale infused my arm-chair knowledge with real-world experience, yielding an alloy whose properties seem to have exceeded its constituent parts.
The scale was nowhere near large enough to measure my satisfaction, but I estimate that this exercise yielded just about one metric ton of fun.
Come to Hive76 on January 21st 10AM – 4PM for a build hackathon focusing on this installation! Some of the things we’ll be focusing on include touch-sensitive light chimes inspired by these, a computer vision-based theremin using Sean’s html5 synth, and altering the brightness of lights based on radio frequency interference. We’ll be splitting up in to teams to work on these problems and have some working prototypes by the end of the day. Stay for an hour or six!
Here’s a hack that managed to make me happier than it probably should have … I was in a phone conference recently and was having trouble juggling my phone while typing on my computer. I really couldn’t leave the meeting and was getting a little irked with the situation … and then I happened to spot a 3×5 index card. A few quick folds and I had a perfectly good phone stand … irk be gone.
I’m not sure why this was such a kick — maybe the fact that it was so simple and stable combined with the fact that I conceived and executed the entire idea while participating in a meeting. Plus, it really was a big improvement in my overall comfort at the moment.
At any rate, if you’re interested in making something similar, I present the following instructional video:
If you are at all interested in cognitive science, some theory behind it, or machine learning, I strongly urge you not to miss this! This will be geared towards folks without math backgrounds, and Josh will stick around to answer questions.
Our Saturday open house event is returning next year, starting on January 7th. So if you can’t make it to our Wednesday night event, feel free to check us out on Saturdays.
Saturday open house starts at 2PM; hope to see you there!
This came in to my inbox this morning. It sounds very interesting, in line with a lot of our core values, especially considering the history of libraries in Philadelphia. I’m a little disappointed because I can’t get in to that part of the city by the necessary time on a weekday, so I won’t be able to go.
After reviewing the projects here and those proposed by NextFab members it sounds like we will be doing some form of the Chess boards, the snowflakes, some robotics, and a bunch of laser-engraving. But what if you don’t like those? Come by anyway and you can rally troops for helping you on your own project(s).
NextFab Studio will have these staff members on hand throughout the event:
Chrinstine : Textile and Industrial Design ( fabric knowledge, product design,cad, sewing )
Ian : Electronics (pcb design/fabrication, coding, wiring, soldering, etc.)
Seth : Mechanical Engineer (handtools, cad, product design)
Brandon : Multi-Media Designer ( 3d printing, graphic design, product design, cinematography, cad)
Just bought myself a Beagle Bone as an early Xmas present. I’m tempted to write a long, gushy tome about it, but for the sake of folks reading this, I’ll restrain myself. I’ll just offer that if you like Arduino, you’ll adore Beagle Bone — in my view, it leapfrogs every physical computing platform out there, and it’s cheap too. I got one for $80 + shipping — about the same price as an Arduino with an ethernet shield — and the BB is about 1000x the machine.
To begin with, it has node.js baked right into its Ångström Linux OS. This node.js installation is extended with a “Wiring-like” API. Then add the fact that BB “sketches” (for lack of a better term) are edited right in your favorite browser, using the Cloud9 IDE. Cloud9 is clean and simple and it supports the essential IDE features that you might expect — a decent editor with code colorization, management of the files that comprise a project, an interactive debugger etc. The idea of a web-enabled physical computing platform that is itself programmed using a web interface seems so obvious and so “right” that it feels like it was always meant to be. Pure elegance meets sheer genius.
At any rate, the fact that this puppy is an outstanding physical computing platform with righteous networking capabilities makes it about the perfect platform for Internet Of Things architectures, so that’s where I’m focusing for now.
Since I have a background in process control systems and a bit of a bias towards Philly-grown tech, I settled on NimBits for my back-end. It has all the attributes of a real process control historian with a cloud architecture and some nice bells and whistles to boot. Since NimBits counts an XMPP based API among its various access methods, I wrote a little study to see if I could send IMs using node.js. Turns out it’s incredibly simple (check out the picture) This app doesn’t push stuff to NimBits (yet), but it’s only a half-step away from it — and being able to have a physical computing platform send you IMs is pretty darn useful in its own right.
Keep an eye out here for more Beagle Bone and Internet Of Things stuff. We live in fascinating times!
Back in late August, when we did the experimentation with ferrofluids, I discovered-for-myself an interesting process for making the requisite Fe3O4, aka magnetite. Through an electrolysis process, and then some other steps, I was able to create a fair amount of magnetite from iron screws. I ditched this process in regards to ferrofluids, but eventually picked it back up again for making paint pigments.
Yes, real paint is pretty cheap, and there are easier ways to make black pigments, such as carbonizing just about anything (though I don’t know of easier ways to make brown from a scratch process). That wasn’t the point. I specifically wanted to make paintings in which I could claim I made the pigments.
From the time of the Renaissance up to the late 19th century, artists often were engineers and scientists, and vice versa. Leonardo Da Vinci should probably be more accurately remembered as a government contractor in weapons engineering rather than artist. Prior to the industrial revolution, any painter kind of had to be a competent chemists to able to make their pigments. And any student of botany, biology, and other natural sciences needed to be competent sketch artists to be able to record their work.
I strive to maintain a lot of that tradition in my own work, and I think it’s important to know what goes in to the things we make, even if that thing is “just art”.
I started with a beaker full of salt water. Ahem, excuse me, “aqueous solution of sodium chloride”. Right. The sodium chloride acts as an electrolyte to allow the electricity to conduct through the water. Basic stuff here. I’ve got a laptop battery charger with alligator clips holding on to the plug. I have iron screws as both electrodes because I didn’t want to bother making sure I had the right polarity on the charger plug. The screws dangle from wires that are taped to my beaker so they stay in place.
WARNING! This process creates a couple of nasty things. First, there will be a small amount of hydrochloric acid produced in beaker. It won’t be a lot, but if you keep your hands submerged in it for long enough, you could get a slight rash (yes, I speak from experience, from many, many years ago when I accidentally blew up my bedroom as a kid). It also creates small amount of chlorine gas, which is poisonous! For the small scale at which I was working, as well as working in a well-ventilated room, it was not a concern. However, I should have used sodium bicarbonate as the electrolyte, it would have eliminated both of these issues. Alas, I didn’t have any at the time.
It also creates a LARGE amount of hydrogen and oxygen gas, which if you’re dumb like I was when I was 15 and try to collect it, can be quite explosive. You are forewarned!
Iron hydroxide painting
The orange stuff floating in the top of the beaker is iron hydroxide. You might not be able to tell from the picture, but there is a slight green tint to rest of the water. That is also iron hydroxide, in another form. Iron hydroxide is apparently very difficult to control in color. However, I did use a little paint brush to sweep up the orange stuff from the edges of my beaker and make this little painting.
The greenish-black iron hydroxide was what I was after. I actually thought it was the magentite iron oxide that I was looking for at the time, but I’ve since learned otherwise. Black iron hydroxide is slightly magnetic, so I balanced my beaker on top of a large, neodymium magnet to draw the precipitate down to the bottom of my beaker, allowing me to pour most of the water off of the top of the stuff I cared about.
It's kind of like silt
I wanted to boil the rest of the water out, as the leftover looked like diluted ink. Eventually I was left with a liquid that was quite thick, almost like river mud, meaning it sputtered too much to continue boiling. The material on the edges dried out and turned brown; more on that in a bit. This was at the time we were doing the ferrofluid stuff, so I was very keen on removing the water and replacing it with a very light oil. One of our members suggested using acetone to dissolve with the water and increase the overall volatility, to speed natural evaporation. At the time, I still didn’t know that I only had iron hydroxide, I thought I had iron oxide, so this step was quite serendipitous. Green-black iron hydroxide in anaerobic conditions will oxidize to magnetite! I believe the acetone deoxygenated the water and left water protons for oxidizing the iron hydroxide. It very clearly went from a greenish-black, pluming precipitate to a very black precipitate fell out of suspension very easily and was much more magnetic. It still didn’t make a great ferrofluid (I didn’t have a surfactant, confused emulsifiers with surfactants, got unconfused and tried to use dish soap as my surfactant, and eventually just had a mess everywhere).
Asteroids
But I was intrigued by how dark of a black I had on my hands, and how readily it stained everything it touched (much to our quarter master’s chagrin). At this point, I had something I could start painting with. I mixed a little with some more water because I knew I wanted to do something spattery, and then made this stylistic interpretation of the classic video game “Asteroids”. There is a little bit of a brown tint to it because of an inefficiency in my process, but then I recontextualized and made it part of my process. I made a frame for it out of scrap wood, but I probably should not have. Now it just kind of looks cheesy. Grumble.
I wanted to now take advantage of the brown crust on the edge of my previous boil experiment. I realized that it was actually another form of iron oxide called hematite, Fe2O3. Magnetite oxidizes to hematite in open air under a flame, so I took some of my black material and blasted it under my pipe welding torch. I eventually shattered my shot glass that I was using as an impromptu beaker from overheating. Yet another instance of my lack of preparation and use of proper tools nearly getting me hurt. But I digress.
Steel Bearing
The last painting was difficult to work with because the water took forever to evaporate, which warped the paper I was painting on. This time, I mixed my pigment with acetone. It was more difficult to keep the pigment in suspension, but the much more volatile acetone evaporated much quicker, leaving me with dry paper that didn’t warp. The result was a painting of a steel bearing, which I thought was interesting because I’m technically painting with “rust”.
Entrance
I finished up with the iron oxide by making an ink with it and this last drawing of the entrance to a mysterious forest.
So now what? Now, I’m experimenting with different metals to see what other colors I can get. I know that copper can lead to some green tints, which I’m very excited to try to replicate. I was able to
Mint-green copper hydroxide
make a very, very small amount of copper hydroxide last night, which you can see in the following pictures. I also made a small amount of yellowish brown copper oxide. Unfortunately, it rather readily oxidizes in air to make black copper oxide, which I’m not too interested in as the black iron oxide is easier to make.
Yellow-brown copper oxide
The brown is nice because it’s not as dark as the brown iron oxide, but I’m excited about the possibility of making green.
I didn’t know how to use an RJ45 crimper at all, so after bugging my fellow members, I just grabbed the crimper and started destroying a patch cable. A few mistakes and pairs of plugs later, I had my own working ethernet cable.
That makes me confident enough to teach you!
Saturday, 12/17 @10am
Come join us for a bit of cable making and Hive76 infrastructure upgrading.
$10 gets you some cable to take home and and a few pairs of RJ45 plugs.
For $18 more, we’ll pick you up a crimper for you as well.
Click below to get some tickets or just RSVP for free and say you’re coming.
