CC279: What’s Ahead in the October Issue

Although we’re still in September, it’s not too early to be looking forward to the October issue already available online.

The theme of the issue is signal processing, and contributor Devlin Gualtieri offers an interesting take on that topic.

Gualtieiri, who writes a science and technology blog, looks at how to improve Improvig Microprocessor Audio microprocessor audio.

“We’re immersed in a world of beeps and boops,” Gualtieri says. “Every digital knick-knack we own, from cell phones to microwave ovens, seeks to attract our attention.”

“Many simple microprocessor circuits need to generate one, or several, audio alert signals,” he adds. “The designer usually uses an easily programmed square wave voltage as an output pin that feeds a simple piezoelectric speaker element. It works, but it sounds awful. How can microprocessor audio be improved in some simple ways?”

Gualtieri’s article explains how analog circuitry and sine waves are often a better option than digital circuitry and square waves for audio alert signals.

Another article that touches on signal processing is columnist Colin Flynn’s look at advanced methods of debugging an FPGA design. It’s the debut of his new column Programmable Logic in Practice.

“This first article introduces the use of integrated logic analyzers, which provide an internal view of your running hardware,” O’Flynn says. “My next article will continue this topic and show you how hardware co-simulation enables you to seamlessly split the verification between real hardware interfacing to external devices and simulated hardware on your computer.”

You can find videos and other material that complement Colin’s articles on his website.

Another October issue highlight is a real prize-winner. The issue features the first installment of a two-part series on the SunSeeker Solar Array Tracker, which won third SunSeekerplace in the 2012 DesignSpark chipKit challenge overseen by Circuit Cellar.

The SunSeeker, designed by Canadian Graig Pearen, uses a Microchip Technology chipKIT Max32 and tracks, monitors, and adjusts PV arrays based on weather and sky conditions. It measures PV and air temperature, compiles statistics, and communicates with a local server that enables the SunSeeker to facilitate software algorithm development. Diagnostic software monitors the design’s motors to show both movement and position.

Pearen, semi-retired from the telecommunications industry and a part-time solar technician, is still refining his original design.

“Over the next two to three years of development and field testing, I plan for it to evolve into a full-featured ‘bells-and-whistles’ solar array tracker,” Pearen says. “I added a few enhancements as the software evolved, but I will develop most of the additional features later.”

Walter Krawec, a PhD student studying Computer Science at the Stevens Institute of Technology in Hoboken, NJ, wraps up his two-part series on “Experiments in Developmental Robotics.”

In Part 1, he introduced readers to the basics of artificial neural networks (ANNs) in robots and outlined an architecture for a robot’s evolving neural network, short-term memory system, and simple reflexes and instincts. In Part 2, Krawec discusses the reflex and instinct system that rewards an ENN.

“I’ll also explain the ‘decision path’ system, which rewards/penalizes chains of actions,” he says. “Finally, I’ll describe the experiments we’ve run demonstrating this architecture in a simulated environment.”

Videos of some of Krawec’s robot simulations can be found on his website.

Speaking of robotics, in this issue columnist Jeff Bachiochi introduces readers to the free robot control programming language RobotBASIC and explains how to use it with an integrated simulator for robot communication.

Other columnists also take on a number of very practical subjects. Robert Lacoste explains how inexpensive bipolar junction transistors (BJTs) can be helpful in many designs and outlines how to use one to build an amplifier.

George Novacek, who has found that the cost of battery packs account for half the DIY Battery Chargerpurchase price of his equipment, explains how to build a back-up power source with a lead-acid battery and a charger.

“Building a good battery charger is easy these days because there are many ICs specifically designed for battery chargers,” he says.

Columnist Bob Japenga begins a new series looking at file systems available on Linux for embedded systems.

“Although you could build a Linux system without a file system, most Linux systems will have some sort of file system,” Japenga says. “And there are various types. There are files systems that do not retain their data (volatile) across power outages (i.e., RAM drives). There are nonvolatile read-only file systems that cannot be changed (e.g., CRAMFS). And there are nonvolatile read/write file systems.”

Linux provides all three types of file systems, Japenga says, and his series will address all of them.

Finally, the magazine offers some special features, including an interview with Alenka Zajić, who teaches signal processing and electromagnetics at Georgia Institute of Technology’s School of Electrical and Computer Engineering. Also, two North Carolina State University researchers write about advances in 3-D liquid metal printing and possible applications such as electrical wires that can “heal” themselves after being severed.

For more, check out the Circuit Cellar’s October issue.

 

 

CC 277: Using Files in Concurrent Linux Designs

In the August issue of Circuit Cellar, columnist Robert Japenga, who has been designing embedded systems since 1973, wraps up his eight-part series on the benefits and challenges of designing concurrency into your systems and some of the specific tools Linux provides for IPC.

His final installment discusses file usage. It also recounts how the development of read/write nonvolatile memory (i.e., flash technology) enabled embedded systems to contain cost-competitive file systems.

“Disk drives in the early days were too big and weren’t reliable enough for embedded systems. The first real disk drive I used in 1975 was a Digital Equipment RK-05 for a PDP-11 that held an amazing 2.5 MB of data,” Japenga says in his column. “The RK-05 was released in 1972. It initially weighed 100 lbs. The $74 monthly maintenance cost would buy a 1-TB drive today or 12 per year.

In 1972, a Digital Equipment RK-05 disk drive held only 2.5 MB of data. (Photo courtesy of Mark Csele)

“In 1977, a friend from Bell Labs carried an RK-05 with a copy of Unix onto a plane. At the gate, the inspector opened the lid and put his finger on the magnetic platter. Whoops. The disk gloriously crashed when inserted into my disk drive. It seemed I would have to wait for my first copy of Unix.

“”For a time, companies produced hardened disk drives. The cost was very prohibitive and the reliability was questionable. Then in 2001, the iPod changed all that when Apple used Toshiba’s 1.8” hard drive, which is only 0.2” thick. As a consumer product, it had to be extremely rugged. Very small embedded systems now had hard drives.

“But not all of us built millions of systems, nor could we afford to put a hard disk in our temperature controllers, motion-control devices, or avionics boxes. However, with the advent of read/write nonvolatile memory (i.e., flash technology), embedded systems now had a way to contain cost-competitive file systems. This paved the way for putting real OSes into embedded systems. In the late 1990s and later, we were putting DOS on a flash card. Well, not everything was a real OS! And that is where Linux comes into the picture.”

Japenga’s column goes on to discuss file systems and the mechanisms to create concurrent systems, including nonvolatile flag files, volatile flag files, data sharing, and event triggering. It concludes with a thorough discussion of some of the risks of using a file system in a concurrent system.

“Modern embedded systems are doing more than I ever imagined when I started out,” Japenga says. “Adding a file system to your design can provide significant advantages to improve your product. As with all OS functions, we need to understand how our file system works if we are going to use it properly—especially in systems with concurrency.”

For more, check out  Japenga’s column, Embedded in Thin Slices, in Circuit Cellar‘s August issue.

Free Raspberry Pi Poster

The Raspberry Pi is a computer with no casing, no keyboard, no hard disk and no screen. Despite all that, it’s taking the world by storm!

Get your free Raspberry Pi poster now, courtesy of Elektor, RS Components, and CC! Go ahead: download, print, and then enjoy!

Free Raspberry Pi Poster

RASPBERRY PI ESSENTIALS

Model A has 256-MB RAM, one USB port, and no Ethernet port (network connection). Model B has 512-MB RAM, two USB ports, and an Ethernet port.

The Raspberry Pi Model B, revision 2 board:

  • Status led labels: top led has label “ACT” and bottom led has label “100”
  • Header P2 is not populated
  • The text underneath the Raspberry Pi logo reads: “(C) 2011,12”
  • The area next to the micro usb port has CE and FCC logos and the text “Made in China or UK” along the board edge.
  • There are two 2.9-mm holes in the PCB, which can be used as mounting holes.
  • P5 is a new GPIO header with four additional GPIO pins and four power pins. Also note that some pin and I2C port numbers of connector P1 have been modified between revisions!
  • Header P6 (left from the HDMI port) was added, short these two pins to reset the computer or wake it up when powered down with the “sudo halt” command.

The Raspberry Pi measures 85.60 mm × 56 mm × 21 mm, with a little overlap for the SD card and connectors which project over the edges. It weighs 45 g.

The SoC is a Broadcom BCM2835. This contains an ARM ARM1176JZFS, with floating point, running at 700 MHz, and a Videocore 4 GPU. The GPU is capable of BluRay quality playback, using H.264 at 40 Mbps. It has a fast 3D core which can be accessed using the supplied OpenGL ES2.0 and OpenVG libraries.

The Raspberry Pi is capable of using hardware acceleration for MPEG-2 and VC-1 playback, but you’ll need to buy license keys at the Raspberry Pi Store to unlock this functionality.

Which programming languages can you use? Python, C/C++, Perl, Java, PHP/MySQL, Scratch, and many more that can run under Linux.

TROUBLESHOOTING TIPS

If you’re getting a flashing red PWR LED or random restarts during the booting process, it’s likely that your PSU or USB cable has problems. The Raspberry Pi is pretty picky and requires a solid 5-V/1000-mA power supply. For other issues and more troubleshooting tips check out the extensive overview at the eLinux website

Circuitcellar.com is an Elektor International Media website.

Member Profile: Thomas Struzik

Member Thomas Struzik at his bench.

 

  • Member Name: Thomas Struzik
  • Location: Houston, TX
  • Education: BSEE, Purdue University
  • Occupation: Software architect
  • Member Status: He has been a subscriber since day one. “I’ve got Issue 1 sitting in a box somewhere,” he said. Thomas adds that he was a BYTE magazine subscriber before Circuit Cellar.
  • Technical Interests: Thomas enjoys automation through embedded technology, robotics, low-level programming, and electronic music generation / enhancement.
  • Most Recent Embedded Tech-Related Purchase: He recently bought a CWAV USBee SX Digital Test Pod and an Atmel AVR Dragon.
  • Current and Recent Projects: Thomas is working on designing an isolated USB power supply for his car.
  • Thoughts on the Future of Embedded Technology: Ever-increasing complexity is becoming a stumbling block for the “average” user. “Few people even realize the technology embedded in everyday items,” he said. “How many people know that brand-new LCD TV they’ve got is actually running Linux under the covers? Fortunately, there seems to be a resurgence of ‘need-to-know how stuff works’ with the whole DIY/maker culture. But even that is still a small island compared to the population in general.”

CC269: Break Through Designer’s Block

Are you experiencing designer’s block? Having a hard time starting a new project? You aren’t alone. After more than 11 months of designing and programming (which invariably involved numerous successes and failures), many engineers are simply spent. But don’t worry. Just like every other year, new projects are just around the corner. Sooner or later you’ll regain your energy and find yourself back in action. Plus, we’re here to give you a boost. The December issue (Circuit Cellar 269) is packed with projects that are sure to inspire your next flurry of innovation.

Turn to page 16 to learn how Dan Karmann built the “EBikeMeter” Atmel ATmega328-P-based bicycle computer. He details the hardware and firmware, as well as the assembly process. The monitoring/logging system can acquire and display data such as Speed/Distance, Power, and Recent Log Files.

The Atmel ATmega328-P-based “EBikeMeter” is mounted on the bike’s handlebar.

Another  interesting project is Joe Pfeiffer’s bell ringer system (p. 26). Although the design is intended for generating sound effects in a theater, you can build a similar system for any number of other uses.

You probably don’t have to be coerced into getting excited about a home control project. Most engineers love them. Check out Scott Weber’s garage door control system (p. 34), which features a MikroElektronika RFid Reader. He built it around a Microchip Technology PIC18F2221.

The reader is connected to a breadboard that reads the data and clock signals. It’s built with two chips—the Microchip 28-pin PIC and the eight-pin DS1487 driver shown above it—to connect it to the network for testing. (Source: S. Weber, CC269)

Once considered a hobby part, Arduino is now implemented in countless innovative ways by professional engineers like Ed Nisley. Read Ed’s article before you start your next Arduino-related project (p. 44). He covers the essential, but often overlooked, topic of the Arduino’s built-in power supply.

A heatsink epoxied atop the linear regulator on this Arduino MEGA board helped reduce the operating temperature to a comfortable level. This is certainly not recommended engineering practice, but it’s an acceptable hack. (Source: E. Nisley, CC269)

Need to extract a signal in a noisy environment? Consider a lock-in amplifier. On page 50, Robert Lacoste describes synchronous detection, which is a useful way to extract a signal.

This month, Bob Japenga continues his series, “Concurrency in Embedded Systems” (p. 58). He covers “the mechanisms to create concurrently in your software through processes and threads.”

On page 64, George Novacek presents the second article in his series, “Product Reliability.” He explains the importance of failure rate data and how to use the information.

Jeff Bachiochi wraps up the issue with a article about using heat to power up electronic devices (p. 68). Fire and a Peltier device can save the day when you need to charge a cell phone!

Set aside time to carefully study the prize-winning projects from the Reneas RL78 Green Energy Challenge (p. 30). Among the noteworthy designs are an electrostatic cleaning robot and a solar energy-harvesting system.

Lastly, I want to take the opportunity to thank Steve Ciarcia for bringing the electrical engineering community 25 years of innovative projects, essential content, and industry insight. Since 1988, he’s devoted himself to the pursuit of EE innovation and publishing excellence, and we’re all better off for it. I encourage you to read Steve’s final “Priority Interrupt” editorial on page 80. I’m sure you’ll agree that there’s no better way to begin the next 25 years of innovation than by taking a moment to understand and celebrate our past. Thanks, Steve.

Elektor & element14 Partner for Embedded Linux Webinar at Electronica 2012

Want to learn more about Embedded Linux? You’re in luck. On Wednesday, November 14, Elektor and Farnell/element14 will partner to run an informative webinar on the topic at Electronica 2012 in Munich, Germany. If you’re at the show, you can attend the recordings for free. Register before October 31 to get free Electronica entry tickets from Farnell/element14.

Attendees should go to the Farnell/element14 stand (Hall 5, Stand 558) for the Elektor Academy seminar, which will focus on the latest developments on the innovative Embedded Linux board. You can watch the presentation and ask the experts questions. The webinar will be recorded and webcast a bit later.

  • Presenter: Embedded Linux expert Benedict Sauter, the board’s designer
  • Description: Benedict Sauter will take you through the design and update us on the latest applications.
  • When: Wed, November 14, 2012
  • Time: 11:30 CET
  • Where: Farnell element14 stand (Messe München, Hall 5, Booth 558)
  • Language: English

Visit the element14 page about the Elektor Academy event for more information and to register for a free entry ticket.

CircuitCellar.com is an Elektor International Media publication.

Elektor Weekly Wrap-Up: E-Blocks, Embedded Linux, & the Elektor Lab

Last week Elektor staffers provided the Circuit Cellar staff with an E-Blocks kit to open and analyze, introduced a new course on Embedded Linux (along with an affordable Linux board), and gave members a behind-the-scenes look at the Elektor Lab. Let’s review.

E-Blocks

Early last week, the Elektor editorial department sent Circuit Cellar staffers an E-Blocks kit to open and review.

E-Blocks: The Elektor Pro PICmicro Starter Kit

So, what are E-Blocks?

E-blocks are small circuit boards. Each contains a block of electronics that you would typically find in an electronic system. The 40 circuit boards in the E-blocks product line use rugged, nine-way, D-type connectors as a connection bus for eight signal lines and earth. Power (5 or 3.3 V) is wired separately. Thus, you can assemble a complete system to be assembled in a matter of minutes.

The system’s functionality can be enhanced further by the addition of more than 40 sensors and accessories.

Systems based on microcontrollers can be programmed using flowcharts, C, or Assembly. Systems based on CPLD/FPGA technologies can be programmed in block diagrams, VHDL or Verilog. A range of CD ROM tutorials, which includes compilers, development tools and manuals, provides support to students who are new to any of these technologies. (Source)

Click here for more information.

Take closer look at the E-Blocks kit. It includes a Microchip Technology PIC16F877A chip, a multiprogrammer board, an LCD board, a switch board, Flowcode, an internal power supply, and documentation.

Embedded Linux Made Easy

Elektor announced last Wednesday an introductory course on Embedded Linux that’s accompanied by a compact circuit board:

In this beginners’ course you will learn where the most important applications and software components, the basis of our Linux system, originate from. You will also learn how the hardware is constructed and how it operates. The next step is to install a suitable Linux development environment on a PC to compile our own source code. By the end of the course you will be able to construct a simple heating controller with a graphical display and data analysis via a browser.

The Linux board features:

  • Two-layer board using readily-available components
  • No special debugging or programming hardware required
  • Fully bootable from an SD memory card
  • Linux pre-installed
  • 180-MHz ARM9 MCU, 8-MB RAM (32 MB optional), 64 MB swap
  • Integrated USB-to-RS-232 converter for console access
  • Relay, external power supply, and pushbuttons for quick testing
  • Four GPIO pins, 3 A/D channels and a PWM channel
  • I²C and SPI buses accessible from Linux
  • USB interface for further expansion

More info.

Workspaces

Circuit Cellar has been publishing workspace writes for the past few weeks. Last week, our colleagues at Elektor gave the world some insight about the Elektor Lab:

Developing electronic circuits necessitates measurement equipment, tools and a good place to work. Many electronics engineers, pro or hobbyist, tinkerers, researchers and other refer to this place as their “Lab”. We at Elektor have our Lab where we develop and test the circuits we publish in the magazine. Over the years, we have collected, (mis)used and destroyed quite a lot of gear, soldering irons and components here, and it is only thanks to regular & rigorous ‘clean-up’ campaigns that we keep our lab workable.

Many of our readers have access to their own often substantial labs, with equipment that sometimes even the NASA would be jealous of. So what does your electronics workspace look like? Our colleagues at Circuit Cellar have begun posting write-ups about workspaces, hackspaces, and “circuit cellars” on their website. If you would like to show off your lab, just send them some pictures and descriptions and they will post it on the Circuit Cellar website. Don’t worry about cleaning up first as our lab is probably in a similar state as yours. (Source)

Email pictures and descriptions of your workspaces, hackspaces, and circuit cellars to our editors.

CircuitCellar.com is an Elektor International Media publication.