Category Archives: EMSL Projects

Retro-tech Style in the New York Times

Component Wine Charms

I’m excited to be included in an article on retro tech style in the New York Times today, titled Nintendo 64s and Vintage PlayStations as Home Décor.

Not surprisingly, these techie hobbyists share their passion in online communities. One of the more popular forums is a D.I.Y. tech blog run by Evil Mad Scientist Laboratories, a family company in Sunnyvale, Calif., that produces open-source hardware. The site features tutorials on making earrings out of linear regulator chips, wine charms from capacitors and a wooden footstool in the shape of a classic 555 integrated circuit chip from the ’70s.

A Diamagnetic Demonstration


Our friends stopped by with a simple apparatus to demonstrate the diamagnetic properties of bismuth metal. Diamagnetism is a extremely weak magnetic effect — generally orders of magnitude weaker than everyday permanent magnets, which exhibit ferromagnetism. However it is also an extremely interesting effect because diamagnetic materials are repelled by magnetic fields. This is different than the case with ferromagnets, where one pole of a magnet repels another — rather, the entire material is (weakly) repelled by any magnetic pole.

Now, how might one observe such a weak effect? One way is to build a magnetic levitation rig, but the field configurations there are a little less obvious. With a simple but sensitive balance, we can see the repulsion directly. The balance above has a long wooden beam, a central pivot on two blocks of plastic, and a couple of coins on the far end for counterbalance.


At the business end of the scale, there is a cylinder of bismuth metal about 1 cm in diameter, held in place by a rubber band. We also have a larger rectangular block, which is our test magnet, made of grade N50 NdFeB and painted black. And finally, the Lego Astronaut Twins are here helping out as a scale and position reference.

Moving the block magnet beneath the bismuth, we can see what happens in an animated GIF:

After the balance settles, the resting position of the end with the bismuth is considerably higher. With some calibration in terms of weights and/or positions, one could even measure the exerted force with some precision.

A slight improvement to this apparatus would be to reverse the roles of the bismuth and the block magnet. That is, to affix the magnet to the arm of the balance, and to slide the bismuth beneath it instead. You could then use a nearby block of aluminum to damp the motion of the beam through magnetic (eddy current) damping. Many commercial balance-beam type scales already use magnetic damping so that they settle down to their final values faster.


Hard Drive Earrings

Wearing my new earrings

The newest in my collection of geeky jewelry: glass hard drive platter earrings.

tiny platters

We picked up a tray of tiny glass platters at a local surplus shop some time ago, marked “Tear Down Qty: 25 pcs.”

CF card for comparison

These one inch platters were used in Microdrives, which were designed to fit into CompactFlash card slots. (Shown with CompactFlash card above for scale.) They were used in (among other things) the iPod mini. After 2006, CF cards outpaced the capacity of the fragile Microdrives, and they’re no longer manufactured.


The platters are attached to the earring hooks with magnet wire. They’re incredibly reflective, and everywhere I wear them, spots of light are dancing around me.

Related: Hard Drive Wind Chimes

The Annotated Build-It-Yourself Science Laboratory

The Annotated Build It Yourself Science Laboratory

We have a book coming out!

Coming soon: The Annotated Build-It-Yourself Science Laboratory is a new, updated version of Build-It-Yourself Science Laboratory, the classic 1960’s hands-on science book by Raymond E. Barrett.

The book is scheduled to make its debut at Maker Faire next week, where I’ll be speaking about it. It’s also available for pre-order now from and other sellers of books, as well as from our store.

We’ll be writing much more about the book once it’s out— about what’s in the book, the process of updating and annotating it, and about the hundreds of project ideas spanning biology, geology, chemistry, physics and more.

However, since we’re already in teaser mode, here are some photos of the original version from the 1960’s:




Fine print: “You can build these and many other experimental items with materials from your home, garage, or local hardware store. Build-It-Yourself Science Laboratory will show you how!”

The Annotated Build It Yourself Science Laboratory


Genetic Algorithm Pattern Generator for EggBot

David Bliss posted about using a genetic algorithm to create designs for the EggBot using Processing. He says, “Each design is a sine wave with eight different parameters.”

Each time the program is run, an initial population is created with 50 individual designs — each with random values assigned to the eight parameters. You then rate each individual design before evolving the next generation. The algorithm chooses individuals to carry on to the next generations (highly rated designs are more likely to be carried forward, but low rated designs may still be used).

Each of the eggs in the photo above was printed from the same program with waves evolved from random seeds.

He has shared his code on Github for this project, as well as earlier ones.

Hands on with NanoBeam


Last fall we wrote about NanoBeam, a new super-miniature open source aluminum T-slot profile construction set that was on Kickstarter at the time. While comparable in design to industrial profile systems like 80/20, its cross section of just 5 mm × 5 mm is comparable to a stud on a lego brick.

We recently got our tweezers hands on a ‘beam, and yes, it’s real, yes, it works, and yes, it’s that tiny. And just wait until you see the fasteners.

Continue reading Hands on with NanoBeam

RoboGames Wrap-up

Eggs decorated by the EggBot at RoboGames
Photo by Jim St. Leger

We had a great time at RoboGames demonstrating the EggBot over Easter weekend. Thanks to the contestants in both Combat and Bartending Art Bots categories that we were privileged to judge.

Photo by Jim St. Leger

Congratulations to our friend RobotGrrl, who took home a gold medal in the Best of Show category.

Schuyler and Roger show off the RoboGames logo as drawn by the WaterColorBot
Photo by Jim St. Leger

Congratulations also to our collaborators on the WaterColorBot project, Schuyler and Roger who won gold in Art Bots in the Painting category.

STEM at the White House Easter Egg Roll

Families gather around to learn more about how the EggBot works

From the White House Office of Science and Technology Policy blog post, An Egg-straordinary Day of Science and Technology:

Interacting with EggBot, an art robot that can paint very intricate and precise designs on eggs. EggBot taught students about digital design, computer numerically controlled machines and robotics. This was also a fun way to celebrate National Robotics Week!