CC264: Plan, Construct, and Secure

Circuit Cellar July 2012 features innovative ideas for embedded design projects, handy design tips with real-world examples, and essential information on embedded design planning and security. A particularly interesting topic covered in this issue is the microcontroller-based home control systems (HCS). Interest in building and HCSes never wanes. In fact, articles about such projects have appeared in this magazine since 1988.

Circuit Cellar 264 (July 2012) is now available.

Turn to page 18 for the first HCS-related article. John Breitenbach details how he built an Internet-enabled, cloud-based attic monitoring system. Turn to page 36 for another HCS article. Tommy Tyler explains how to build a handy MCU-based digital thermometer. You can construct a similar system for your home, or you can apply what you learn to a variety of other temperature-sensing applications. Are you currently working on a home automation design or industrial control system? Check out Richard Wotiz’s “EtherCAT Orchestra” (p. 52). He describes an innovative industrial control network built around seven embedded controllers.

John Breitenbach's DIY leak-monitoring system

The wiring diagram for Tommy Tyler's MCU-based digital thermometer

The rest of the articles in the issue cover essential electrical engineering concepts and design techniques. Engineers of every skill level will find the information immediately applicable to the projects on their workbenches.

Tom Struzik’s article on USB is a good introduction to the technology, and it details how to effectively customize an I/O and data transfer solution (p. 28). On page 44, Patrick Schaumont introduces the topic of electronic signatures and then details how to use them to sign firmware updates. George Novacek provides a project development road map for professionals and novices alike (p. 58). Flip to page 62 for George Martin’s insight on switch debouncing and interfacing to a simple device. On page 68, Jeff Bachiochi tackles the concepts of wireless data delivery and time stamping.

Jeff Bachiochi's hand-wired modules

I encourage you to read the interview with Boston University professor Ayse Kivilcim Coskun on page 26. Her research on 3-D stacked systems has gained notoriety in academia, and it could change the way electrical engineers and chip manufacturers think about energy efficiency for years to come. If you’re an engineer fascinated by “green computing,” you’ll find Coskun’s work particularly intriguing.

Special note: The Circuit Cellar staff dedicates this issue to Richard Alan Wotiz who passed away on May 30, 2012. We appreciate having had the opportunity to publish articles about his inventive projects and innovative engineering ideas and solutions. We extend our condolences to his family and friends.

Circuit Cellar Issue 264 (July 2012) is now available on newsstands. Go to Circuit Cellar Digital and then select “Free Preview” to take a look at the first several pages.

HackMiami: UAV Design, Cybersecurity, & More

Miami isn’t just a destination for the Heat vs. Thunder NBA Finals, world-renowned clubs, five-star restaurants, and professional beach lazing. It also boasts an evolving technology scene with tons of monthly events (e.g., game hackathons, app-building workshops). A notable contributor to the city’s culture of innovation is HackMiami, a hackerspace where professionals, students, and innovators can “invent/develop new technologies, develop new skills, enhance old skills, collaborate with other like minded individuals to create something that is better than what they can do on their own.”

The group’s multitalented members work on projects as diverse as secure servers and UAV designs (see video below).

Below are images Rod—one of the group’s members—submitted of the hackerpace.

HackMiami meets at the "Planet Linux Caffe" (Source: HackMiami)

HackMiami meets at the “Planet Linux Caffe” (Source: HackMiami)

HackMiami runs events such as workshops and contests such as the Homebrew Antenna Contest at DEFCON XX in Las Vegas, NV.

After reviewing the photo submissions, I asked Rod for a bit of info about the group. He quickly filled me in.
C. J.: What are we looking at in the photos? Is that HackMiami’s actual space or are you holding an event a local establishment?

Rod: We hold our meetings at Planet Linux Caffe in Coral Gables, Florida. Planet Linux Caffe is a Open Source community place.

C. J.: What is the group’s “mission” or purpose?

Rod: We are hackerspace based in Miami, FL. We focus on information security and vulnerability research.

C. J.: What is your group like? Do members come from diverse tech backgrounds? How often do you meet?

A HackMiami meeting on the topic of cyber weapons (Source: HackMiami)

A HackMiami meeting on the topic of cyber weapons (Source: HackMiami)

Rod: We have an open-door policy. Everybody welcome, we have people from ALL ages and ALL backgrounds. We meet every two weeks. Here is where we publish our meetings: meetup.com/hackmiami.

C. J.: Does HackMiami do any work with embedded tech (e.g., embedded security, MCU-based designs, etc)?

Rod: We have done some work with DD-WRT, Plug Servers, Pinapples, Arduino, etc.

C. J.: Tell us about the quadracopter project. When did you build it? How many group members were part of it? Can you tell our readers about some of the parts you used (e.g., MCU, motor controls, etc)?

Rod: This was done in December 2011. There were around five people involved in the project. The idea is in principle to create a network of communicating self resilient UAVs. Here is the list of the parts for the drone. For more information please contact Twitter handle @d1sc0rd1an.

Wrapping up, I mentioned to Rod that we’re always looking for interesting projects to share with the embedded design/programming community. He said HackMiami members likely will be working with Raspberry Pi in the near future. Sounds exciting. We can’t wait to see what the group develops.

 

Show us your hackerspace! Tell us about your group! Where does your group design, hack, create, program, debug, and innovate? Do you work in a 20′ × 20′ space in an old warehouse? Do you share a small space in a university lab? Do you meet a local coffee shop or bar? What sort of electronics projects do you work on? Submit your hackerspace and we might feature you on our website!

In Memoriam: Richard Alan Wotiz

Richard Alan Wotiz—a multitalented electronics engineer, inventor, and author—provided the international embedded design community with creative projects and useful electronics engineering lessons since the early 1980s when he graduated from Princeton University. Sadly, Richard passed away unexpectedly on May 30, 2012 while hiking with a group of friends (a group called “Take a Hike”) in Santa Cruz County, California.

Richard Alan Wotiz

Richard started writing his “Embedded Unveiled” column for Circuit Cellar magazine in 2011. You can read each of his columns by clicking the links below:

Prior to becoming a columnist, Richard placed highly in several international embedded design challenges. Amazingly, he won First Prize in both the Texas Instruments 2010 DesignStellaris Challenge and the 2010 WIZnet iMCU Challenge. That’s right—he won First Place in both of Circuit Cellar’s 2010 design challenges!

Richard published intriguing feature article about some of his prize-winning projects. Interestingly, he liked combining his passion for engineering with his love of the outdoors. When he did so, the results were memorable designs intended to be used outdoors: a backpack water level monitor, an earth field magnetometer, and an ABS brake system for a mountain bike.

Richard’s ABS system is built around a Texas Instruments EKK-LM3S9B96 evaluation board, which contains the Stellaris LM3S9B96 microcontroller and support circuitry. The mechanism mounts to the front fork in place of the reflector, and the control unit sits on a bracket that’s also attached to the handlebars. A veritable maze of wires runs to the various sensors on the brake levers and wheels.

His other projects were well-built systems—such as his single-phase, variable-speed drive for AC induction motors—intended to solve real-world problems or handy DIY designs—such as his “Net Butler” network control system—that he could use in his daily life.

Richard’s single-phase, variable-speed drive for AC induction motors is an excellent device for powerful, yet quiet, pump operation. Designed for use with a capacitor-start/capacitor-run motor, it includes active power factor correction (PFC) and inrush current limiting. This is the drive unit. A Microchip Technology dsPIC30F2020 and all of the control circuitry is at the upper right, with all of the power components below. The line filter and low-voltage supplies are in a separate box to the left. It’s designed to sit vertically with the three large filter capacitors at the bottom, so they stay as cool as possible.

Richard named his finished network control system the “Net Butler.” This innovative multifunctional design can control, monitor, and automatically maintain a home network. Built around a WIZnet iMCU7100EVB, the design has several functions, such as reporting on connected network devices and downloading Internet-based content.

I last saw Richard in March 2012 at the Design West Conference in San Jose, CA. As usual, he stopped by our booth to chat about his work and Circuit Cellar magazine in general. He had a great passion for both, and it showed whenever I spoke with him. He was a true believer of this magazine and its mission. During our chat, he asked if he could write about the seven-processor Intel Industrial Control Robotic Orchestra system on display at the conference. I agreed, of course! His enthusiasm for doing such an article was apparent. Soon thereafter he was at the Intel booth taking photos and notes for his column.

I’m happy to announce that the column—which he titled “EtherCAT Orchestra”—will appear in Circuit Cellar 264 (July 2012).

Richard’s work was a wonderful contribution to this magazine, and we’re grateful to have published his articles. We’re sure Richard’s inventive design ideas and technical insight will endure to help countless more professionals, academics, and students to excel at electronics engineering for years to come.


Q&A: Aubrey Kagan (Engineer, Author)

Aubrey Kagan is a talented engineer with years of experience designing embedded systems. He’s also a prolific author. Between 2000 and 2010 he published 15 articles with Circuit Cellar on topics ranging from developing an AC current generator to resilience in embedded designs. His 2004 book Excel By Example: A Microsoft Excel Cookbook for Electronics Engineers provides tips on using Excel for engineering computations, data analysis, circuit modeling, and more.

In Circuit Cellar 263 (June 2012), Kagan opens up in a candid interview with editor Nan Price. Below is an abridged version of an interview that currently appears in Circuit Cellar 263.

AUBREY KAGAN: I live on the northern edge of Toronto, Ontario, Canada. However, that belies my accent, which the readers obviously cannot hear. I was born and grew up in “deepest, darkest Africa” just north of Rudyard Kipling’s “great gray-green, greasy Limpopo River” (see “How the Elephant Got Its Trunk” from Kipling’s Just So Stories) in what is now called Zimbabwe (then Rhodesia). I did my undergraduate engineering degree at the Technion, Israel Institute of Technology, and then returned to Africa for my MBA at the University of the Witwatersrand in South Africa. My early years in engineering were spent in South Africa, immigrating to Canada in 1989.

NAN PRICE: What is your current occupation?

AUBREY: I am an engineering manager at Emphatec, although managing occupies only a small portion of my day—the majority of my time is engineering. Most of the projects are for industrial monitoring and control. They tend to be a blend of analog and digital approaches and usually are quite compact with only a single function.

Engineer and author Aubrey Kagan

NAN: How long have you been interested in designing embedded systems?

AUBREY: I was given the opportunity to get into embedded design long before anybody thought to call it that. It was in 1977, and all we had were microprocessors, which I was trying to design into HF radio transceivers. I had been struggling with phase lock loops and control of the frequency divider seemed a likely candidate for computer control. Just at that time, there was an article in Popular Electronics on creating an evaluation board for the RCA CDP1802 COSMAC microprocessor. I used that as the basis for the development and as they say, the rest is history.

NAN: Circuit Cellar Online featured your article, “Developing an AC Current Generator” (119, 2000). Tell our newer readers about that project. Do you still use the generator? Have you made any upgrades to it?

AUBREY: That was my first Circuit Cellar article and my only collaborative effort (with Ernesto Gradin). It is probably my favorite project because it is so unusual and remains pertinent to this day.

This AC current generator is one of Kagan’s favorite projects.

Some of the products that we make involve monitoring an AC current and converting the measurement to a 4-to-20-mA analog signal. Some of the devices will measure currents up to 100 A AC. In order to test and calibrate these units, obviously you need an accurate current. If you use a variable AC voltage into a fixed load or a fixed voltage into a variable load to generate the current, you will be working with dangerous voltages and lots of heat. This leads to errors due to heating and more importantly health risks to the operators. We all know in transformers (VIN × IIN) = (VOUT × IOUT) and VIN = (N × VOUT) and so if you make a transformer with a low number of output turns, there is a low output voltage, and for a given power input you can then derive a high current—no heat and very low voltage. To improve the performance, we added a feedback loop with a micro then implemented PID control. The generator is still in use. I have not made any upgrades to it, but I certainly could improve upon it now. I would like to increase its resolution, and of course some of the components are now obsolete, so they would need revision. I might consider onboard displays as well, not control from a PC.

NAN: Your 2002 article series, “Driving the NKK SmartSwitch” (Circuit Cellar 144 and 145), focused on using a Cypress Microsystems programm-able system-on-chip (PSoC) microcomputer as an interface to drive the SmartSwitch. Tell us how this project came about.

AUBREY: Signal conditioning modules in the process-control market tend to be physically small, typically 2” high by 3” deep by 0.75” wide. Of course, there are many much bigger and smaller examples. All of them mount on a rail installed in a panel. Aside from some LED indications, there is very little information you can glean by just looking at the modules. As a result, there has been a slow trend in the industry to add displays to each individual module. Because of the size, the displays are small and are limited to seven-segment displays of up to four digits and sometimes some indicators, if a custom LCD has been used. Also, the displays are invisible when the panel door is closed. The NKK SmartSwitch would allow three lines of six alphanumeric characters and even some graphics. It would also allow the user to change operational parameters for the module. The NKK projects through the panel door and so the information is available to the outside world.

Simply driving the display was the focus of my discussion in Circuit Cellar. At the time, the article had the distinction of being used as an application note by two different companies simultaneously (NKK and Cypress).

But there is much more to the story. If an NKK SmartSwitch and driver were added to a single module, it would probably double the effective price of the module, and so we came up with a networked approach that allowed a single NKK SmartSwitch to be shared among up to 30 different modules spreading the costs and now becoming economically more viable.

Circuit Cellar 263 (June 2012) is now available.

CircuitCellar.com Featured on EEWeb

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Circuit Cellar celebrates 25 years!

Visit CircuitCellar.com each day for embedded design and programming projects, news, tutorials, and more!

Also, to celebrate the Circuit Cellar’s 25th anniversary, the company has a special archive thumb drive promotion. Check it out. Get 25 years of articles and projects on a 32-GB thumb drive! Click here for details.