Category Archives: Engineering

A Peggy 2 Word Clock

By Windell Oskay on October 8, 2012

Justin Shaw of WyoLum recently presented with this little slice of awesome: One of our own Peggy 2 kits, adapted into a great big “word clock” with the help of custom software and laser-cut acrylic.

WyoLum is a small but international collective of Open Source Hardware enthusiasts who collaborate on hardware designs and other projects (like their Open Hardware Grants) that promote Open Source Hardware. One of their great ongoing projects has been a series of open source word clocks, ClockTHREE and ClockTHREEjr, which drew inspiration from a number of sources including QlockTWO, Doug Jackson’s word clocks, and the open source design of our Peggy 2 kit.

This is, of course, one of the great things about designing Open Source Hardware: seeing unexpected uses. When we first released the Peggy 2, we didn’t even remotely consider that others would later use our circuit diagram for tips on building their own RGB word clocks. And now it’s especially neat to see it come full circle, with the ClockTHREE software adapted to work back on the Peggy.

WyoLum’s design files for the Peggy 2 word clock are available for download here (by kind permission), and if you’re building one, you may also find helpful the ClockTHREE repository and our own documentation page for the Peggy 2.

Photo by Brian Krontz of WyoLum.

This entry was posted in Electronics, EMSL Projects and tagged peggy 2, word clock. Bookmark the Permalink.

Field Trip: Bell Labs Technology Showcase

By Lenore Edman on October 4, 2012

Bell Labs in Murray Hill, New Jersey is one of the sites that should be on every geek pilgrimage itinerary.

Their Technology Showcase is a enshrined in a small exhibit area off of the main lobby. In the center of the exhibit, on a pedestal of its very own, is the first transistor. It looks like a very small piece of mixed media abstract sculpture, with geometric forms and wires bent in wonderful angles. If that were the only thing to see, it would still be worth the visit.

Nearby, the first MOSFET sits in an impressive array of other firsts, including an early CCD and a micro-mirror array.

Telstar, the world’s first active communications satellite hangs overhead. This one is a flight backup unit that was never used.

These fiberoptic preforms were placed under a polarizer so that the optical qualities of the cores would be more apparent to visitors.

There are many more beautiful objects, as well as interactive wall for exploring many world-changing developments that happened at and through Bell Labs.

Huge thanks go to Drew Fustini of Pumping Station: One for organizing our post-Maker Faire pilgrimage via twitter and driving us all up to New Jersey.

This entry was posted in Engineering, Field Trips, Open Hardware and tagged lego, open source. Bookmark the Permalink.

Open Hardware Summit and Maker Faire New York

By Lenore Edman on September 24, 2012

We’re very excited to be heading to New York for the sold-out Open Hardware Summit next week. There is another fantastic lineup of speakers this year, and it will be good to have the opportunity to catch up with the community after an eventful year for open source hardware.

After that, we’ll be going to Maker Faire New York, where you can find us demoing our kits in the Maker Shed.

We’ll be on the Make Demo Stage with the Egg-Bot on Saturday at 2:30 and Sunday at 3:00.

We hope to see you there!

This entry was posted in Eggbot, Engineering, Field Trips, Open Hardware and tagged eggbot, makerfaire, open hardware summit. Bookmark the Permalink.

From the mailbag: flickering LEDs in series

By Lenore Edman on September 19, 2012

We recently got a question about our flickering LEDs:

I’m wondering if it’s possible to wire these in series?

It’s a good (and not entirely uncommon) question, and the short answer is: “Yes, but not with each other.”

These LEDs have a little chip inside that turns them on and off in a flickering pattern. You can see it in the photo of the flat-topped white LED above. On the upper pad is the yellowish phosphor over the LED die. On the lower pad is the chip that turns the LED on and off.

If you put two of these in series, the first one turns the next one on and off repeatedly, interrupting the second chip and preventing it from executing its flickering pattern. The result is that you get momentary blinking, but not the nice flickering pattern. (So yes, both would in fact light up; they just don’t behave how you might hope that they would.)

So how can you hook up a bunch of flickering LEDs together? If you want each LED to flicker separately, you can hook them up in parallel. But there is a way to use these in series with other LEDs. We can even use this to combine multiple LED colors to create some fantastic LED “flames” that would be great for stage props or putting inside pumpkins.
Continue reading From the mailbag: flickering LEDs in series →

This entry was posted in Electronics, EMSL Projects and tagged Halloween, LEDs. Bookmark the Permalink.

Vector engraved stipples

By Lenore Edman on September 14, 2012

Over at rasterweb, Pete has been playing with StippleGen2 to create artwork with the laser engraver at the Milwaukee Makerspace.

StippleGen’s output consists of lots of tiny overlapping circles and this piece was made by using vector engraving, where the laser traces out each circle individually. In some places, the lasered marks overlap many times, leading to a new and unusual surface texture. In the closeup above you can see the ridges and valleys formed by the overlapped engraved areas. Go check out his article for the rest of the story about the project!

This entry was posted in CNC, Everything Else and tagged cnc, engraving, makerspace. Bookmark the Permalink.

The Art Controller

By Windell Oskay on September 12, 2012

Today we’re releasing a new open source kit: A stand-alone, microcontroller-driven relay module called the Art Controller.

The Art Controller project was originally suggested by our friends (and Maker Faire regulars), San Francisco Bay Area kinetic artists Christopher T. Palmer and Nemo Gould. Amongst other things that they build are amazing mechanical sculptures that need to run for a little while after a visitor presses a button or inserts a coin into the slot.

The long-established solution for driving electronic artwork (along with many similar endeavors) is to use a timer relay module; a little stand-alone board with a relay controlled by a timer. There are several types of these: fancy programmable modules, bulletproof industrial types, and simple low-cost boards with a 555 timer and a pot that you turn to adjust the delay. As we understand it, Christopher and Nemo go through the latter type like jellybeans. But, what they realized that they really wanted was something just like that, except that you could reprogram it if you wanted to.

Hence the Art Controller. It’s a low cost stand-alone relay module, with an on-board AVR microcontroller, an ATtiny2313, that manages the timing and I/O.

It can be used as a replacement for one of those basic 555-based relay boards, but it’s considerably more flexible in terms of timing range and functionality:

The timing is adjusted with an 8-position DIP switch, rather than a knob. This cuts down on guess-and-check, but also gives a huge range. With those 8 little switches, you can select times from 1 second to 31 hours. (The ranges are 1-31 seconds, minutes, or hours, plus a few intermediate ranges.)
It can work as a one-shot timer or a continuously repeating timer.
There’s an option to trigger automatically upon turn-on (reset).
There’s a separate cancel input, so you can build a “STOP” button.
There’s an option to cancel a trigger if you push the “START” button a second time.

It comes preprogrammed, and all of those adjustments can be done with switches and wiring— handy if solder is your favorite programming language —so no computer or programming are actually required to get that far.

But, when that’s not enough, the on-board microcontroller can be reprogrammed in situ (using the board’s AVR ISP programming header) to handle the most specialized applications, potentially taking advantage of up to 16 free digital I/O pins.

And that’s pretty neat.

Beyond the obvious applications in DIY projects, automation, and controlling art projects, we think that this is also going to be a fantastic relay board for education. It starts out as a (well-designed) simple function timer relay board, but can optionally transition to a full-on microcontroller development board when you’re ready for it.

So that’s the Art Controller in a nutshell: a versatile, easy to use, low-cost relay board that you can reprogram if you want to.

There’s plenty more detail on our product page: The Art Controller at Evil Mad Science.

And, special thanks to Christopher T. Palmer and Nemo Gould for a great project idea!

This post is included in our Halloween Project Archive, where you can find ideas for props, decor, and more.

This entry was posted in Electronics, EMSL Projects, Microcontrollers and tagged art controller, AVR. Bookmark the Permalink.

Makerspace Launch

By Lenore Edman on September 9, 2012

The Makerspace program is a joint effort by O’Reilly’s Make division and Otherlab to put dedicated space and tools for hands-on making into high schools. They describe their aims on their about page:

By creating makerspaces in an educational context, students can have access to tools and equipment that they might not have otherwise; they can collaborate on projects that are driven by their own interests, and by doing so, develop the capacity and confidence to innovate. We see making as a gateway to deeper engagement in science and engineering but also art and design.

On Monday, September 10, we’ll be attending the Makerspace launch event at the College of San Mateo. We’ll be demoing a few kits and are excited to have the opportunity to meet educators interested in bringing making into the classroom. If you’ll be attending, please stop by our table and say hi!

This entry was posted in Art, Education, Engineering, Field Trips, Open Hardware, Science and tagged art, makerspace, science. Bookmark the Permalink.

Mailbag: Hacking a Mega-Peggy

By Windell Oskay on August 31, 2012

Tony writes in with a question about hacking our DIY LED matrix kits:

“I’m building a Peggy 2LE. I have completed the wiring with the exception of the LEDs. I have constructed an external frame which has 600 mounting points for my LEDs using a Matrix design of wires crossing every 3 inches. Since the Peggy 2LE has 625 LEDs I need to know how I can drive the 30 anode connections and 20 cathode connections to the wiring them to the Peggy 2. Or am I going to have to wire each LED to the PCB of the Peggy + and – LED locations?”

And, that’s actually an interesting topic. We’ve written before (here and here) about some giant-scale variations and modifications to our Peggy 2 and Peggy 2LE LED matrix kits, but we haven’t really addressed how one might go about building it.

First off, since you asked— and though we recommend against it —it is indeed possible to build an off-board LED matrix by simply running individual running wires from every LED location on the Peggy circuit board to every LED. There are 625 LEDs in a 25 × 25 grid, and if each has two wires… that turns out to be quite a few wires.

While *ahem* labor intensive, this method does work. We know this partly because several people have actually done it. The “rats nest” of thin, red-lacquered magnet wire shown above is one example, and the Peggy shown here is another ~~victim~~ example of this method.

Fortunately, very fortunately, there are easier ways: think 50 wires, rather than 1250. And, there are a few other clever tricks that you might want to consider when changing the size of the matrix. For example, it’s possible to use the Peggy 2LE to drive an off-board LED matrix of size up to 25 × 32 without adding any other extra hardware.

Continue reading Mailbag: Hacking a Mega-Peggy →

This entry was posted in Electronics, EMSL Projects and tagged electronics, peggy 2. Bookmark the Permalink.

Basics: Picking Resistors for LEDs

By Lenore Edman on August 29, 2012

So… you just want to light up an LED. What resistor should you use?

Maybe you know the answer, or maybe everyone already assumes that you should know how to get to the answer. And in any case, it’s a question that tends to generate more questions before you actually can get an answer: What kind of LED are you using? What power supply? Battery? Plug-in? Part of a larger circuit? Series? Parallel?

Playing with LEDs is supposed to be fun, and figuring out the answers to these questions is actually part of the fun. There’s a simple formula that you use for figuring it out, Ohm’s Law. That formula is V = I × R, where V is the voltage, I is the current, and R is the resistance. But how do you know what numbers to plug into that formula to get out the right resistor value?

Continue reading Basics: Picking Resistors for LEDs →

This entry was posted in Basics, Electronics, EMSL Projects and tagged electronics, LEDs, resistors. Bookmark the Permalink.

Prefabricated Octolively Modules

By Windell Oskay on August 2, 2012

Last year we released Octolively, an open source interactive LED kit, designed to respond in gentle and complex ways to stimulus provided by human interaction.

While Octolively has been a success (and a lot of fun), thus far it has only been available as a soldering kit. Today, we’re pleased to supplement those with a new version: prefabricated Octolively modules, all built-up and ready-to-use, so you can jump right in and start playing with the LEDs.

Like the soldering kit version, each “prefab” Octolively module is 4 × 8 inches (10.16 × 20.32 cm) in size, and features eight huge (10 mm) ultrabright LEDs, spaced along a two-inch grid. And, for every LED, there is an independent infrared proximity sensor pair, configured to act as a reflective motion sensor.

The most obvious change from the soldering kit version of Octolively is that the topside components take up a lot less space. All of the resistors, capacitors, and the microcontroller have been replaced by their surface mount equivalents.

However, this not really a “surface mount” circuit board, it’s more accurately a “mixed technology” board. Some of the components— in particular many “optoelectronic” components, like our visible and infrared LEDs —just don’t have great surface mount versions. For example, when we’ve tried building motion sensors circuits with SMT infrared LEDs (even the pricier types that have itty-bitty lenses) we found that they just didn’t project enough IR light to be effective. Similarly, we’ve found that visible surface mount LEDs tend to be perceived as dim, even when a huge amount of light is being emitted, because the light usually goes into a very wide angle.

The microcontroller is an Atmel ATmega164A, in the 44-pin TQFP package. (And in case you’re wondering, yes that’s exactly as redundant as “ATM machine.” )

Those white gumdrop-looking things are (as before) the big 10 mm LEDs, but they certainly seem even bigger sitting next to that chip.

Ready-to-use Octolively modules are available now at Evil Mad Science.

Additional details— including the datasheet and documentation links —are available on the product page.

This entry was posted in Electronics, EMSL Projects, Evil Mad Scientist Shop and tagged LEDs, octolively. Bookmark the Permalink.