CC268: The History of Embedded Tech

Posted on 2012/10/23 by C. J. Abate

At the end of September 2012, an enthusiastic crew of electrical engineers and journalists (and significant others) traveled to Portsmouth, NH, from locations as far apart as San Luis Obispo, CA, and Paris, France, to celebrate Circuit Cellar’s 25th anniversary. Attendees included Don Akkermans (Director, Elektor International Media), Steve Ciarcia (Founder, Circuit Cellar), the current magazine staff, and several well-known engineers, editors, and columnists. The event marked the beginning of the next chapter in the history of this long-revered publication. As you’d expect, contributors and staffers both reminisced about the past and shared ideas about its future. And in many instances, the conversations turned to the content in this issue, which was at that time entering the final phase of production. Why? We purposely designed this issue (and next month’s) to feature a diversity of content that would represent the breadth of coverage we’ve come to deliver during the past quarter century. A quick look at this issue’s topics gives you an idea of how far embedded technology has come. The topics also point to the fact that some of the most popular ’80s-era engineering concerns are as relevant as ever. Let’s review.

In the earliest issues of Circuit Cellar, home control was one of the hottest topics. Today, inventive DIY home control projects are highly coveted by professional engineers and newbies alike. On page 16, Scott Weber presents an interesting GPS-based time server for lighting control applications. An MCU extracts time from GPS data and transmits it to networked devices.

The time-broadcasting device includes a circuit board that’s attached to a GPS module. (Source: S. Weber, CC268)

Thiadmer Riemersma’s DIY automated component dispenser is a contemporary solution to a problem that has frustrated engineers for decades (p. 26). The MCU-based design simplifies component management and will be a welcome addition to any workbench.

The DIY automated component dispenser. (Source: T. Riemersma, CC268)

USB technology started becoming relevant in the mid-to-late 1990s, and since then has become the go-to connection option for designers and end users alike. Turn to page 30 for Jan Axelson’s tips about debugging USB firmware. Axelson covers controller architectures and details devices such as the FTDI FT232R USB UART controller and Microchip Technology’s PIC18F4550 microcontroller.

Debugging USB firmware (Source: J. Axelson, CC268)

Electrical engineers have been trying to “control time” in various ways since the earliest innovators began studying and experimenting with electric charge. Contemporary timing control systems are implemented in a amazing ways. For instance, Richard Lord built a digital camera controller that enables him to photograph the movement of high-speed objects (p. 36).

Security and product reliability are topics that have been on the minds of engineers for decades. Whether you’re working on aerospace electronics or a compact embedded system for your workbench (p. 52), you’ll want to ensure your data is protected and that you’ve gone through the necessary steps to predict your project’s likely reliability (p. 60).

The issue’s last two articles detail how to use contemporary electronics to improve older mechanical systems. On page 64 George Martin presents a tachometer design you can implement immediately in a machine shop. And lastly, on page 70, Jeff Bachiochi wraps up his series “Mechanical Gyroscope Replacement.” The goal is to transmit reliable data to motor controllers. The photo below shows the Pololu MinIMU-9.

The Pololu MinIMU-9′s sensor axes are aligned with the mechanical gyro so the x and y output pitch and roll, respectively. (Source: J. Bachiochi, CC268)

CC267: Continuity of Embedded Tech Content

Posted on 2012/09/26 by C. J. Abate

The October issue features articles on topics ranging from FAT cache to IIR digital filters to a quadcopter that uses a mechanical gyro. Let’s review.

Jeff’s quadcopter uses a mechanical gyro that is “an inexpensive yet elegant attempt to counteract wind gusts.” With its protective shield removed, you can see the motorized spinning rotor that sustains equilibrium as its frame moves.

On page 16, Stuart Oliver details how to use math routines that include the dsPIC hardware features, such as the accumulators and barrel shifter. He uses the math for implementing Assembler routines.

Turn to page 30 to learn how Kerry Imming uses FAT cache for SD card access. You can implement his cache technique in a variety of other applications.

Before you start a new project, familiarize yourself George Novacek’s tips on managing project risk (p. 34). He explains how to define, evaluate, and handle risk. Better yet, why not just reduce risk by avoiding as many problems as possible?

Bob Japenga addresses this issue as well (p. 38). In the third part of his series on concurrency in embedded systems, he details how to avoid concurrency-related problems, which can be difficult because the more concurrency you add to a project, the more complicated it becomes.

Ed Nisley presented a MOSFET tester in his August 2012 article, “MOSFET Channel Resistance.” In this issue, Ed covers temperature measurement, the control circuitry, the firmware’s proportional integral control loop, and more (p. 42).

A fan under the black CPU heatsink keeps it near ambient temperature, so that the Peltier module under the aluminum block can control the MOSFET temperature. The gray epoxy block holds a linearized thermistor circuit connected to the Arduino microcontroller under the PCB. (Source: E. Nisley)

Check out Robert Lacoste’s article on page 58 for an introduction to IIR digital filters. You’ll learn about the differences between IIR filters, FIR filters, and analog filters.

WinFilter allows you to calculate and simulate all kind of IIR filters just by entering their key characteristics (left). The plots shows you the resulting frequency and time behavior. (Source: R. Lacoste)

Working with an unstable mechanical gyro? As Jeff Bachiochi explains, a MEMS system is the solution (p. 68).

Lastly, check out the interview with Helen Li on page 54. You’ll find her impressive research exciting and inspirational.

CC266: Microcontroller-Based Data Management

Posted on 2012/08/27 by C. J. Abate

Regardless of your area of embedded design or programming expertise, you have one thing in common with every electronics designer, programmer, and engineering student across the globe: almost everything you do relates to data. Each workday, you busy yourself with acquiring data, transmitting it, repackaging it, compressing it, securing it, sharing it, storing it, analyzing it, converting it, deleting it, decoding it, quantifying it, graphing it, and more. I could go on, but I won’t. The idea is clear: manipulating and controlling data in its many forms is essential to everything you do.

The ubiquitous importance of data is what makes Circuit Cellar’s Data Acquisition issue one of the most popular each year. And since you’re always seeking innovative ways to obtain, secure, and transmit data, we consider it our duty to deliver you a wide variety of content on these topics. The September 2012 issue (Circuit Cellar 266) features both data acquisition system designs and tips relating to control and data management.

On page 18, Brian Beard explains how he planned and built a microcontroller-based environmental data logger. The system can sense and record relative light intensity, barometric pressure, relative humidity, and more.

a: This is the environmental data logger’s (EDL) circuit board. b: This is the back of the EDL.

Data acquisition has been an important theme for engineering instructor Miguel Sánchez, who since 2005 has published six articles in Circuit Cellar about projects such as a digital video recorder (Circuit Cellar 174), “teleporting” serial communications via the ’Net (Circuit Cellar 193), and a creative DIY image-processing system (Circuit Cellar 263). An informative interview with Miguel begins on page 28.

Turn to page 38 for an informative article about how to build a compact acceleration data acquisition system. Mark Csele covers everything you need to know from basic physics to system design to acceleration testing.

This is the complete portable accelerometer design. with the serial download adapter. The adapter is installed only when downloading data to a PC and mates with an eight pin connector on the PCB. The rear of the unit features three powerful
rare-earth magnets that enable it to be attached to a vehicle.

In “Hardware-Accelerated Encryption,” Patrick Schaumont describes a hardware accelerator for data encryption (p. 48). He details the advanced encryption standard (AES) and encourages you to consider working with an FPGA.

This is the embedded processor design flow with FPGA. a: A C program is compiled for a softcore CPU, which is configured in an FPGA. b: To accelerate this C program, it is partitioned into a part for the software CPU, and a part that will be implemented as a hardware accelerator. The softcore CPU is configured together with the hardware accelerator in the FPGA.

Are you now ready to start a new data acquisition project? If so, read George Novacek’s article “Project Configuration Control” (p. 58), George Martin’s article “Software & Design File Organization” (p. 62), and Jeff Bachiochi’s article “Flowcharting Made Simple” (p. 66) before hitting your workbench. You’ll find their tips on project organization, planning, and implementation useful and immediately applicable.

Lastly, on behalf of the entire Circuit Cellar/Elektor team, I congratulate the winners of the DesignSpark chipKIT Challenge. Turn to page 32 to learn about Dean Boman’s First Prize-winning energy-monitoring system, as well as the other exceptional projects that placed at the top. The complete projects (abstracts, photos, schematic, and code) for all the winning entries are posted on the DesignSpark chipKIT Challenge website.

Issue 265: Embedded Systems Abound

Posted on 2012/07/24 by C. J. Abate

I recently read on CNN.com the transcript of an interview (May 9, 2002) with arachnologist Norman Platnick who stated: “You’re probably within seven or eight feet of spider no matter where you are. The only place on earth that has no spiders at all—as far as we know—is Antarctica.” It didn’t take long for me to start thinking about embedded systems and my proximity to them. Is the average person always within several feet of embedded systems? Probably not. But what about 50% or 60% of the time? E-mail me your thoughts.

Circuit Cellar 265, August 2012 - Embedded Development

Embedded systems are becoming ubiquitous. They’re in vehicles, mobile electronics, toys, industrial applications, home appliances, and more. If you’re indoors, the temperature is likely monitored and controlled by an embedded system. When you’re engaged in outdoor activities (e.g., hiking, golfing, biking, or boating), you probably have a few MCU-controlled devices nearby, such as cell phones, rangefinders, pedometers, and navigation systems. This month we present articles about how embedded systems work, and our authors also provide valuable insight about topics ranging from concurrency to project development.

Freescale’s Mark Pedley kicks off the issue with a revealing article about a tilt-compensating electronic compass (p. 16). Now you can add an e-compass to your next MCU-based project.

E-compass technology (Source: M. Pedley, CC265)

Turn to page 24 for an in-depth interview with Italy-based engineer Guido Ottaviani. His fascination with electronics engineering, and robotics in particular, will inspire you.

Have you ever come across a product that you know you could have designed better? Scott Weber had that experience and then acted on his impulse to build a more effective system. He created an MCU-based light controller (p. 32).

The MCU-based light controller is on the right (Source: S. Weber, CC265)

If you want to ensure a microcontroller works efficiently within one of your systems, you should get to know it inside and out. Shlomo Engelberg examines the internal structure of an I/O pin with a pull-up resistor (p. 40).

Bob Japenga continues his series “Concurrency in Embedded Systems” on page 44. He covers atomicity and time of check to time of use (TOCTTOU).

On page 48 George Novacek presents the second part of his series on project development. He covers project milestones and design reviews.

Ed Nisley’s June 2012 article introduced the topic of MOSFET channel resistance. On page 52 he covers his Arduino-based MOSFET tester circuitry and provides test results.

The MOSFET tester PCB hides the Arduino that runs the control program and communicates through the USB cable on the left edge. (Source: E. Nisley, CC265)

If you read Robert Lacoste’s June 2012 article, you now understand the basics of frequency mixers. This month he presents high-level design methods and tools (p. 58).

Jeff Bachiochi wraps up the issue with an examination of a popular topic—energy harvesting (p. 68). He covers PV cell technology, maximum power point tracking (MPPT), and charge management control.

A great way to investigate MPPT for your design is to use an STMicroelectronics evaluation board, such as this STEVAL-ISV006V2 shown in the top of the photo. The smaller cell in the center is rated at 165 mW (0.55-V output at 0.3 A) measuring 1.5” × 0.75”. At the bottom is a Parallax commercial-quality solar cell that is rated at 2.65 W (0.534-V output at 5.34 A) measuring 125 mm. (Source: J. Bachiochi, CC265)

Circuit Cellar 265 is currently on newsstands.

CC264: Plan, Construct, and Secure

Posted on 2012/06/21 by C. J. Abate

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.