Make Sparks in Your Parlor

Wimhurst Machine from MAKE Volume 17

In the early 1880s, British inventor James Wimshurst created an electrostatic generator called the Wimshurst Influence Machine, influence machines being a class of generators that separate electric charges through electrostatic induction, or influence. Not only did the sparks created by the machine provide for great scientific demonstration, but experiments like the “electric kiss” were popular parlor pastimes. In MAKE Volume 17, a fine gentleman by the name of Jake von Slatt shared his detailed instructions for making one. We just ported the DIY into Make: Projects for all to build. How does it work?

Wimshurst Machine MAKE Volume 17

The counter-rotating disks continually pass their metal strips (or sectors) near one another, and then separate them, increasing the sectors’ electrical potential or charge. A pair of neutralizing bars with conductive brushes contact each sector while it’s still under electrostatic influence, grounding its positive side and leaving it with a negative charge, or vice versa. A pair of charge-collecting combs strip off the charges — negative on one side and positive on the other — and deliver them to the Leyden jars where they are stored. When sufficient voltage builds up, a spark jumps the gap between 2 electrodes — CRACK!

Head over to the build on Make: Projects for tools, materials, crystal clear photos, step-by-step instructions, and an option to download the project as a PDF. Your parlor will never be the same.


The Beatty Family Builds Bots Together

Robert Beatty sent us these wonderful pictures of his daughters, “Lunamoth” and “Julajay,” building robots. His “maker girls,” as he calls them, have been…

…involved in the designing, soldering, electronics, metal fabrication, programming, and naming of the robots, and testing, with Dad guiding the way. We really enjoy it.

Our two most recent robots are a Mars Rover, complete with a NASA-style rocker-bogie suspension system, and a mechatronic tank with mecanum wheels. We’ve also built quad rotors, crawlers, and others. Be sure to watch the Mars Rover and Mechatronic Tank videos.

Beatty Robotics

See the Robotics Area of Make: Projects and the Robotics Archive here on


Zero to Maker: Knowing What You Don’t Know

David Lang, something of a reluctant maker, is on a journey, intensively immersing himself in maker culture and learning as many DIY skills as he can, through a generous arrangement with our pals at TechShop. He’s regularly chronicling his efforts in this column — what he’s learning, who he’s meeting, and what hurdles he’s clearing (um… or not). –Gareth

I just got back from New York City where Eric Stackpole and I spent the weekend exhibiting and talking about OpenROV at the Open Hardware Summit and World Maker Faire. Although it wasn’t quite as big as Maker Faire Bay Area, it was an unbelievable gathering of makers and creators of all shapes and sizes. On a scale of 1 to Awesome, it was a perfect score.

David at the OpenROV booth at World Maker Faire

There were a number of events and interactions that I could take away (and will) from the experience for the Zero to Maker column, but one conversations stands out above all others.

Just as the Faire was winding down for the evening on Saturday, Gareth Branwyn, Editor-in-Chief of the MAKE website, stopped by the OpenROV booth to check in. Gareth was the one who I initially pitched this column idea to, and the entire column has really been an outgrowth of that conversation. Over the past few months, Gareth and I have traded numerous emails and talked several times over the phone, but this was the first time we were meeting in person. With a number of underwater robots on the table, the conversation naturally started there, but after an extensive overview of OpenROV, he ask me, “So, looking back, have far do you think you’ve gone from Zero to Maker?”

Although I should’ve been more prepared for it, the question took me by surprise. It was the first time I had really taken stock of everything I’ve learned so far. I certainly didn’t feel like I had made any real progress. In fact, I hadn’t built much more than a few projects for the different classes I’d taken. Thinking back to an illustration I had seen during Nathan Seidle of Sparkfun’s presentation at the Open Hardware Summit, I answered with a “You know what? I think I’m getting there.”

I then went on to explain this graphic from the presentation:

Note: I’ve recreated the graph and it’s WAY out of scale – my yellow box is much, much bigger than depicted.

Nathan told us that his goal was to continually expand the green slice – that’s how he measures his growth. For me, the same is true about my journey. Of course, my blue slice has increased, but not nearly as fast as the green one, and that’s good. My original goal was learning “enough to be dangerous” which, to me, means knowing how to ask good questions, and then, knowing where to begin looking for answers (I added the “Enough to be Dangerous” line to the graph for emphasis). If that’s my measurement, then I’m getting to that point, but like everything worthwhile, the more you know, the more you realize what you have to learn. Also, fortunately, making is a positive (additive) feedback loop where the more you make, the more you want to make.

One thing is certain: I’m starting to think like a maker. In my mind, I’m mentally deconstructing everything I come across – wondering how it works, trying to take it apart, figuring out if I can build it myself. I’m jumping at the opportunity to fix things; no longer seeing that as a tedious task, rather an exciting learning opportunity. I’m viewing the world differently.

Looking back, the only real danger was in not getting started. To quote the Arduino team from their presentation at the Open Hardware Summit: “Don’t let not knowing what you’re doing stop you from getting started.”

Editor’s Note: It was great meeting David. He’s good people, very personable, smart, and passionate about what he’s doing. I think he’s also overly humble and cautious about his abilities. He knew the answer to every question I asked about the OpenROV (which is very cool in person, BTW). We talked about the fabrication of the chassis and parts, the controls, the to-be-designed software interface, the motors, cabling, waterproofing issues, and more. At one point, after the above exchange he describes, I said: “Sounds to me like you know a lot about this hardware and how it all works.” He said, humbly: “I’ve just been sitting here listening to these guys explain it over and over.” I don’t believe him. I think he knows more than he admits. Which, I guess, is not knowing what you DO know (?) I awarded the OpenROV project one of my Make: Editor’s Choice blue ribbons. I can’t wait to see this thing in action. -Gareth

Follow David’s Zero to Maker journey


Identifying Unknown Plastics

This is a piece of free-burning ABS tubing showing characteristic flame color and smoke. The burn test, as it’s known, correlates a plastic sample’s composition with a set of observable properties including…

  1. whether or not the material will freely burn in air when a gas ignition flame is removed,
  2. the color of the flame,
  3. the smell,
  4. the presence or absence of molten drips, and
  5. the color and properties of any smoke, esp. the reactivity of smoke with wet litmus paper.
Though useful, the burn test should be used with caution of the toxicity of many plastic combustion products, and need not be a first resort when confronted with a sample of unknown polymer.

To risk stating the obvious, the first step in identifying a piece of plastic should be to look for a label. Since 1988, the SPI resin identification coding system (Wikipedia) has been widely adopted by plastics manufacturers to label their products for post-consumer recycling. Though the variety of possible plastic materials is essentially infinite, the familiar SPI recycling codes are a useful basic taxonomy of the polymers one is likely to encounter “in the wild.”

SPI # Abbreviation Name Example Use Density (g/mL)
1 PETE/PET Polyethylene terephthalate Water bottles 1.37-1.45
2 HDPE High-density polyethylene Milk jugs 0.93-0.97
3 PVC Polyvinyl Chloride Pipe 1.3-1.45
4 LDPE Low-density polyethylene Saran wrap 0.91-0.94
5 PP Polypropylene Food containers 0.85-0.94
6 PS Polystyrene Model kits 1.05
9 ABS Acrylonitrile butadiene styrene Lego bricks 1.04

Assuming your sample has no label that would indicate its composition, then, the test which offers the best combination of safety, utility, and convenience is probably density. If your sample is made of a single material, solid through and through, its density can be checked against a set of reference liquids of known densities by simply dropping the sample in a small vial of each liquid: If it floats, it is less dense than the reference, and if it sinks, it is more dense than the reference. Polyethylenes and polypropylenes float in water (density = 1 g/mL), for instance, while most other plastics sink. Among heavier-than-water plastics, ABS and PS will float in glycerin (density = 1.26 g/mL), but PETE and PVC do not.

Other useful tests for discriminating plastics are the Beilstein copper wire test (which indicates the presence of chlorine, e.g. in PVC), susceptibility to acetone (most plastics besides polyethylene and polypropylene will become “tacky” on exposure), and whether the plastic turns white under stress, e.g. when bent (PVC whitens; PET does not).


Arduino Leonardo Opens Doors to Product Development

The Arduino Leonardo is one of the latest boards announced by the Arduino team at World Maker Faire. It’s not going to replace the Arduino Uno, but provide an additional alternative. It’s a lower cost Arduino board using only surface mount components and simpler circuit, and it really excites me.

Leonardo’s IC is the ATmega32u4, which has all of the features of the ATmega328, an additional 0.5k SRAM, and built-in USB support. While the chip has already been used with the Arduino IDE before (Teensyduino), this will bring full support to it in the Arduino 1.0 IDE. I haven’t had a chance to test the Leonardo with the latest Arduino IDE build, but I will write more about it once I get a chance to sit down and play with both a bit.

I really like the 32u4, as it is more easily found and less likely to have shortages like we have seen with the 328. The 32u4 is nearly the same price and has built in USB, so there’s no need for an expensive FTDI chip. By my guess, this means the Leonardo will retail for around $20-25. In the future, this will also allow for smaller Arduinos with everything needed already on-board.

The Leonardo is entirely SMD, similar to the Sparkfun Pro series, where everything but the through-hole parts are populated on the board and already soldered. Leonardo customers will have to solder their own headers and power jack. I think this decision is fine, as it reduces the costs further, and people aren’t nearly as scared of soldering as they once were. I’ve really seen the maker community grow over the past few years, and beginners are working on SMD projects more and more. I’m hoping to see a ton of people building their own custom Arduino boards with the 32u4. SMD is honestly easier than through-hole if you have the right stuff, and with PID re-flow ovens and laser cut-able stencils at lots of hackerspaces, it keeps getting easier.

What really excites me is how this will start to open the door for people to make their own open source products that are pre-made and store-ready. You can actually get your hands on 10k 32u4s for a product run. The lower cost of parts and simpler circuit design will help people bring their costs down, and have competitive prices at retail. And being fully supported by Arduino will make it easier for people to make the jump from prototype to product.

As projects grow in size and scope, they will be ready for something like the Arduino Duo, which will have a 32bit Cortex-M3 ARM processor. This will give people plenty of room in which to learn and develop. I think the Arduino Duo is going to make even more things possible going forward, but I really like the Leonardo for its ability to bring nearly anyone into larger scale projects. I’m a huge fan of anything that allows people to learn easily.

The open hardware scene is still quite young, but it’s growing at a quick rate with so many amazing people making things and learning from each other. Events like the Open Hardware Summit this past weekend really gives me encouragement that things in the open hardware scene are going in positive directions, as we are already starting to make waves in the culture at large.

I look forward to the day that I can go into just about any store and buy a piece of hardware that I fully own and can make changes to as I feel. Not something completely proprietary that I have to hack just to get it to work the way I want, but something I have the choice to hack simply because I want to. The Leonardo with full Arduino support for the ATmega32u4 has us taking a few more steps towards that future. I can’t wait to see what products people come up with.

Bio: Jimmie Rodgers a full-time hacker, artist, author, musician, and whatever else he feels like. He travels the world teaching people how to make things and he designs and sells open hardware kits. His most popular kit is the LoL Shield for the Arduino, a 14×9 LED matrix with a lot of LEDs.


Schuyler Towne’s 24-Part Online Lockpicking Course

Schuyler Towne, the locksport aficionado who rode the Kickstarter wave to the tune of $87K, has uploaded a 24-part lockpicking course to YouTube. I can’t wait to dive in!


How-To: Drifting Robot Car (video)

Learn how to make a drifting robot car with a few cheap components and some simple code in this tutorial episode of The Latest in Hobby Robotics.

The car used in the video is a “Fast Lane RC Monster Drift 1:24″ by Maisto Tech. It’s sold in many webshops and on eBay. You can download the code used in the video on Let’s Make Robots. I used the PICAXE 08M on AXE230 microcontroller (by Revolution Education) and the SRF05 ultra-sonic rangefinder (by Devantech). As for tools, I used the DSO nano pocket oscilloscope by Seeed Studio (available in the Maker Shed), and the simple servo tester by Gadget Gangster.

Subscribe to the The Latest in Hobby Robotics Podcast in iTunes, download the m4v video directly, or watch it on YouTube or Vimeo.

Check out all the episodes of The Latest in Hobby Robotics.



“18650 Things To Do With An Old Laptop Battery”

As much as I enjoyed this unusual technical info from GeekDad contributor Roy Wood, I was disappointed to learn that not all 18,650 things you can do with an old laptop battery are specifically listed in the article. Moreover, by a truly amazing coincidence, “18650″ turns out to be the part number for the most common size lithium-ion cell used in assembling laptop batteries.

Three 18650s are pictured above, and as you can see, they are slightly larger than AA batteries. Importantly, they are also much, much more dangerous, and Roy goes to great and appropriate lengths to emphasize that opening a laptop battery and extracting the cells for your own projects is very hazardous.

If you are competent to negotiate those hazards, however, and are interested in recovering 18650s from old batteries and putting them to use, Roy’s article is a pretty good starting place. The individual cells are very powerful, and since a single bad cell can kill the entire battery, there is potentially a lot of value to be recovered. [via Boing Boing]


Reno Hackerspace Opening

Bridgewire is a member-funded, non-profit makerspace, hackerspace, workshop located in Sparks, NV serving the Reno-Sparks area. We’ve been busy recently preparing for our Grand Opening on Saturday, October 1st at noon.

We invite you to attend for a free BBQ, tour of our facility and a rare opportunity to meet and talk to Reno’s own Hotshot the Robot. The Grand Opening is currently the best time to come by and see what we’re all about. We are working on scheduling events and trying to determine hours that we’ll be available for facility tours.

Can’t believe they passed on “Sparks” in the name, but I guess you have to go with the bigger neighbor….


Atlanta Mini Maker Faire — Follow-Up Report

The Atlanta Mini Maker Faire was held on September 10, 2011 at the Georgia Tech campus — nice (but hot) weather, easy parking, and over 60 exhibitors allowed visitors plenty of time to stop, look, chat, and even make some purchases. I asked the event’s coordinator, Eric Weinhoffer, if he could provide some more details about the event, as well as attendance figures and any lessons learned that might help other Mini Maker Faire coordinators in the future.

The first Atlanta Mini Maker Faire was a success! Our exhibitors were fantastic, and completely understanding of some of the hiccups we encountered, since it was our first time. They were helpful, accepting, and showed off amazing work. They interested our guests, and hopefully inspired many of them to make something of their own. Next year we hope to expand and improve the Faire. We will consider moving off campus, where there aren’t as many restrictions, and it will probably be easier to find a large venue. We would also like to include speakers and more performers next year; hopefully we’ll have a stage to put them on. Due to the intensity of the sun we faced this year, I’d like to provide more pop-up tents and fluids to our exhibitors next year as well. The setup period was also extremely hectic due to fact that most exhibitors showed up at the same time; next year we’re going to split the exhibitors into groups, which will arrive and setup at different times. We would also like to have more sponsors for the next year’s event. Our estimated attendance was roughly 2,000 guests. My advice to other MMF organizers is to keep your head up, work hard, and enjoy it! It’s definitely worth the hard work you put into it in the end.

I think Eric’s estimates on attendance might be a bit conservative, but he’s right that the event was a big success — from 10am to 5pm, the event had a consistent coming-and-going of attendees of all ages, and kids especially had a great time seeing the R2-D2 Builders Club show off their droids, numerous robots on display, and a variety of artisans including a blacksmith (the kids loved Sean O’Shea of Industrious Designs and his nails made into swords) and a glass blower.

Some photos from the event are starting to be uploaded on the Flickr group page — if you were in attendance and have some additional photos, please consider adding them to the group page.

You can view a complete list of all the exhibitors– a few notable callouts that I enjoyed:

  • the pickup truck converted to electric power
  • the Freeside ATL hackerspace group
  • the brand new My Inventor Club, a 6400 square foot shop that will begin selling memberships and offering training to residents of Atlanta and surrounding areas.

I’d also like to thank Fashionable Notes and Allen Digital Fine Art for talking to me about their small businesses and their design ideas and inspirations — only at a Mini Maker Faire could I find a booth selling reusable market bags across from a booth selling artwork created from photographs and computer-generated algorithms.

Plans are already in place for next year’s Atlanta Mini Maker Faire, so if you missed attending or coming as an exhibitor, mark your calendars and bookmark the Atlanta Mini Maker Faire site for news starting next spring.

Below you’ll find a handful of my own photos from the event that include the R2-D2 Builders Club and Sean the Blacksmith.

R2-D2 Builders Club
We had a nice assortment of droids on hand — the adults loved them just as much as the kids, but the group did have to keep asking folks to move along… “these aren’t the droids you’re looking for.”

The Designer Is In
Those with engineering or design questions could get their questions answered at a ridiculously low price on Saturday.

JD Warren's Segbot
JD Warren, inventor of the LawnBot 400 (Make Volume 22) was on hand to show off his robot designs, including this Segway clone. (I got to ride it — worked great!)

Similar to JD’s LawnBot 400, NagliTech had their E-Goat on hand, a remote controlled lawnmower that will soon incorporate GPS for hands-free mowing.


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