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November 20, 2009

PYMT, a multi-touch library for Python

Interested in building programs with fancy multi-touch interfaces? Speak Python? Well, in that case you might want to have a look at PYMT. Designed for rapid interface design, it looks like it would be fun to play around with. [via the space station]

November 17, 2009

Homemade transistor from a photocell?

Like many of us, Nyle Steiner has long aspired to building a homemade transistor. While considering possible way to achieve this, he stumbled upon the interesting idea of building a FET transistor from a cadmium sulfide photocell.

Normally used to detect light, the photocell is pretty close to what one would need to make a transistor. The device consists of two pieces of metal that are separated by a very thin layer of a cadmium sulfide semiconductor. The semiconductor is normally an insulator, which means that no electricity can flow from one of the metal legs to the other. However, when light (photons) hit the surface of the semiconductor, they knock electrons free, and allow some current to flow across the semiconductor. To make a transistor, though, the device needs to react to electricity, not light. Nyle realized that the photocell could be used as a transistor if an insulated gate was added to the top of it. A bit of scotch tape and water later, and he claims to have a working transistor.

Of course, this isn't a truly homemade transistor, it's more of a DIY transistor conversion. The device appears to be functional, however it requires fairly high voltages to work, and only acts as a power amplifier instead of a voltage amplifier. Even so, it looks like an interesting way to experiment with transistors at home. I'd like to build one, and vary thickness of the insulator (scotch tape) to see what the results are. Anyone else have experience with this?

November 16, 2009

DIYLILCNC, a open hardware CNC mill

Artists Chris Reilly and Taylor Hokanson appear to be getting some impressive results from their DIYLILCNC. They certainly aren't the first to develop an open source CNC mill, however their build looks particularly nice. They claim that the whole thing can be assembled for around $700, including the stepper motors and drive electronics. Want to get in on the action? CAD drawings for the parts and build instructions are available on their site, under the Creative Commons license. [via core77]

October 26, 2009

Bringing a '20s radio back to life

Got an old radio from the '20s, and want to bring it back to life? Well, the quickest way is probably be to remove all those dusty components and use the cabinet to hide a new stereo. That's not what radio hacker Greg Charvat had in mind for his, though. Instead, he restored the original radio circuitry, and even hooked it up to his iPod.

Along the way, he ran into all sorts of neat discoveries, and many potential pitfalls. It turns out that electronics have changed quite a bit in the past 80 years, and even the most basic components such as resistors and capacitors can be unrecognizable. Another issue is that the cloth and rubber used for insulation on the wiring will have dried out, making it necessary to handle everything extremely carefully. One nice thing about equipment of this vintage, however, is that it was usually designed to be repaired, so chances are good that a schematic is available.

To give you an idea of the issues one should expect to encounter when attempting this, here is the overview he gives in a presentation about the project:

Do not power up your radio!
yes, it does not work
more harm than good
Find service manual
Replace all electrolytic and paper capacitors
Replace anything that looks damaged (burned or exploded)
Try radio (wear safety glasses)
Signal trace through circuit, replacing resistors where needed
Radio will work

As usual for high-voltage projects, and especially for high-voltage projects involving unknown vintage equipment, don't attempt this unless you have the proper training, because the electronics inside are most certainly deadly. Don't give up though, just make sure you learn enough to know what you are doing!

October 25, 2009

MassTEC Conference

Last week, at the annual MassTEC conference, an interesting collection of technology engineering education, science, and math teachers gathered to share experiences and information. Here are some highlights:

Johanna Bunn, of the Boston Museum of Science, introduced the Engineering the Future curriculum, with interactive demonstrations of hands-on projects introducing students to structures, fluids, and electricity.

The forum on the Massachusetts state science and technology curriculum frameworks introduced a series of strand maps that show how the concepts and possible activities in the various STEM subjects interrelate. Their hope is that existing and new courses could be designed so that they step students through learning ideas within courses and how the courses could build upon each other. Right now, the maps are static PDFs, but their goal is to have them be more interactive in the way they connect projects and concepts.

Martha Cyr, Director of K-12 Outreach at the Worcester Polytechnic Institute, showed the TEACHEngineering site, which has resources for K-12 teachers. The site's search engine allows teachers to find curriculum and projects that map to many states' frameworks, and loads of scientific and engineering concepts. The curriculum tools on the site have a consistent look and feel and have been tested by STEM teachers.

Nate Ball of Design Squad told of his experiences in backyard, garage, and kitchen making. Though his school in Oregon lacked a hands-on technology and engineering program, his childhood was filled with adventures of the making sort. His rigorous personal projects and academic record led him to MIT, where he discovered what engineers do. When WGBH uncovered a need for youth to understand more about the realities and techniques of engineering, he was in a group of students who helped to develop possible projects for the show before he tested for and ultimately filled the role of host. The show encourages creativity, teamwork, and real world problem solving. The third season of Design Squad has just begun airing, and the site has lots of curriculum resources, and full episodes of the show.

If you are involved in an organization helping to prepare teachers and their students for a lifetime of making, pass along some links in the comments.

October 22, 2009

In the Maker Shed: Snap Circuits Jr. kit

Curious young minds can learn the basics of electronics with the Snap Circuits Jr. kit from the Maker Shed. You can build more than 100 projects with this award-winning kit including sound effects, alarms, touch circuits, and games. No soldering is required. It's a great way to teach your kids about electronics!

October 21, 2009

"The joy of sex don't last like the fun of shootin' anvils"

To "shoot," an anvil, for the record, is to blast it several hundred feet into the air using a charge of black powder. This delightful man, Gay Wilkinson, is apparently the world's champion anvil-shooter. The fireworks start at 1:30. [via Boing Boing]

Gear clock is both functional and structural

Alan Parekh of Hacked Gadgets made this really nice looking gear clock using a PIC microcontroller, a scavenged stepper motor, and a bunch of wooden gears that he cut out on a CNC router. The concept is pretty straightforward, however I really like the clear design, where each part is a functional piece of the clock mechanism. You'll never have to wonder what is inside this thing that makes it tick! [via Hacked Gadgets]

October 19, 2009

Awesome little needle-felted dragon

By deviantART user ~tallydragon. [via CRAFT]

October 14, 2009

RepRap "Mendel" plans available

Have you been waiting for the new RepRap "Mendel" design files? If you have, your wait is over. All the files are ready to download, including the mechanics, electronics, firmware, and software. There is also a great wiki with tons of build information.

October 13, 2009

Giant hand torments city goers

Here's an excellent use for a giant LED billboard: a crazy augmented reality installation. The appropriately titled Hands From Above was made by artist Chris O'Shea. Want to create your own? You might run into trouble finding such a nice billboard to use, however the programming environments he used- openFrameworks and openCV - are both freely available. His source code doesn't seem to be available though, unfortunately. [via interactive architecture]

DIY CNC router comes alive!

These days, homebrew CNC machines seem to be losing popularity to 3d printers. These are all well and good, however there are situations where you really need a part made of solid metal or wood, and for those there is no substitute to a good ol' CNC machine. So, it's nice to see that Jonny D is making progress on his homebrew CNC router. After getting a sweet deal on a suitable mechanical frame and stepper motors, he has managed to get his version up and running, and has successfully used it to engrave wood and drill PCBs. He's still working on improving the system, however this early success should be a great motivator to get everything finished up. Excellent work!

October 12, 2009

New in the Maker Shed: FX Master Bundle - 5 DVDs

The FX Master Bundle includes all 5 of our Effects Master Class DVDs! Each DVD is 3 hours long and packed with lessons taught by professional artists, most of whom work in Hollywood at effects houses including Stan Winston Studio, Spectral Motion, KNB and Motion Picture F/X, and teach part-time at Los Angeles-area effects schools like Westmore Academy, Makeup Designory, FX School and USC.

Halloween Special: Use promo code "SAMHAIN" at checkout and receive FREE 3 day FedEx on our FX Master Bundle (contiguous US only)

Lightfader floor remembers where you were

While we're on the topic of low-tech visualizers, here is another neat one. This Lightfader floor has a (presumably slow moving) fluid in it, that gets displaced when you step on it, and then slowly returns to it's original state. This produces a footprint path that slowly fades away, without any electronics. It is a few years old, however I just became aware of it.

It kind of reminds me of what happens to your footprints when you walk down a beach, and then the waves wash them away. I'm guessing it is made of a thin layer of very viscous, tinted liquid. Think that would work, or does it have to be something more complicated? Perhaps some sort of liquid crystal-based polarizer, to improve the contrast? [via transmaterial]

Seeing RFID on the cheap

The folks at BERG developed this neat method for visualizing the sensitivity of an RFID reader. Rather than using an expensive set of test equipment to measure the magnetic field intensity, they just hooked their reader up so that it lit an LED every time their card was detected, and then captured it using a camera. This is pretty similar to the technique used to make the Roomba art. They were also able to show that (due to polarization) the orientation of the card with respect to the sensor changes how it responds. Fascinating!

October 7, 2009

Thats no rock! It's a cardboard stone.

I'm digging the rocks supporting this 'Agua Table' by designer Domingos Tótora. Though they look totally real, they are actually made of recycled paper and glue. His website is made of unlinkable flash, however Contemporist has a nice set of photos showing how they are made.

The table is pretty nice, but I think I would want to make a giant boulder and roll it towards my anthropologist friends. What would you make out of fake rock? [via curbly]

High-visibility paracord luggage handle wrap

I'd like to reassure everyone that Stormdrane is not paying me under the table. But public denials cost an extra $50 and he won't pony up the dough. So you're just gonna have to wonder. Seriously, I think I can't stop clicking through his blog because I'm looking for a "practical" excuse to tie one of these awesome knots. So far, this is the best one I've found. I may actually have to cave in and buy some neon paracord.

How to make a slip ring connection for a spinning sign

I'm working on a new project and I need an electrical connection that can rotate 360 degrees. I could purchase a slip ring, rotating electrical connector, or better yet a rotary transformer. Then again, I could just try to make one from a DC motor. Do you have any suggestions for making, or *gasp* buying, a slip ring connectors? If so leave them in the comments. Thanks!

In the Maker Shed:

MiniPOV kit

October 6, 2009

Thomas Bloch plays the glass armonica

This instrument is known both as a "glass harmonica" and a "glass armonica," and I personally favor the latter spelling to distinguish it from the better-known free-reed mouth harp also called a "harmonica." The tone of a glass armonica is stunningly beautiful; a great 18th-century myth is that the purity of its sound will eventually drive a virtuoso to madness. Thomas Bloch's website has more info about his work and about the particular custom-built instrument shown here. [via Neatorama]

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