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Circuit Cellar's editorial team comprises professional engineers, technical editors, and digital media specialists. You can reach the Editorial Department at editorial@circuitcellar.com, @circuitcellar, and facebook.com/circuitcellar

Freescale High-Sensitivity Accelerometer Family

Freescale recently introduced a new range of three-axis accelerometers offering high sensitivity at low power consumption. According to Freescale, the FXLN83xxQ family is capable of detecting acceleration information often missed by less accurate sensors commonly used in consumer products such as smartphones and exercise activity monitors. In conjunction with appropriate software algorithms, its improved sensitivity allows the new sensor to be used for equipment fault prognostication (for predictive maintenance), condition monitoring, and medical tamper detection applications.

Source: Freescale

Source: Freescale

The 3 mm × 3 mm chip has a bandwidth of 2.7 kHz and uses analog output signals for direct connection to a microcontroller’s ADC input. Each chip has two levels of sensitivity that can be changed on the fly. The complete family covers acceleration ranges of ±2, ±4, ±8, and ±16 g, with gains of, 229.0, 114.5, 57.25, and 28.62 mV/g, respectively. Zero g is indicated by an output level of 0.75 V.

The FXLN83xxQ family:

  • FXLN83x1Q ±2 or ±8 g range
  • FXLN83x2Q ±4 or ±16 g
  • FXLN836xQ 1.1 kHz x- and y-axis bandwidth (Z = 600 Hz)
  • FXLN837xQ 2.7 kHz x- and y-axis bandwidth (Z = 600 Hz)

The sensors operate from 1.71 to 3.6 V (at 180 µA typically, 30 nA shutdown). The company has also made available the DEMOFXLN83xxQ evaluation break-out board with a ready-mounted sensor to simplify device integration into a test and development environment.

Professor’s Convertible Electronics Workspace

In addition to serving as a contributor and technical reviewer for Circuit Cellar, Chris Coulston heads the Computer Science and Software Engineering department at Penn State Erie, The Behrend College. He has a broad range of technical interests, including embedded systems, computer graphics algorithms, and sensor design.

Since 2005, he has submitted five articles for publication in Circuit Cellar, on projects and topics ranging from DIY motion-controlled gaming to a design for a “smart” jewelry pendant utilizing RGB LEDs.

We asked him to share photos and a description of the workspace in his Erie, PA, home. His office desk (see Photo 1) has something of an alter ego. When need and invention arise, he reconfigures it into an “embedded workstation.”

Coulston's workspace configured as an office desk

Photo 1: Coulston’s workspace configured as an office desk

When working on my projects, my embedded workstation contains only the essential equipment that I need to complete my project (see Photo 2).  What it lacks in quantity I’ve tried to make up for in quality instrumentation; a Tektronix TDS 3012B oscilloscope, a Fluke 87-V digital multimeter, and a Weller WS40 soldering iron.  While my workstation lacks a function generator and power supply, most of my projects are digital and have modest power requirements.

Coulston can reconfigure his desk into the embedded workstation pictured here.

Photo 2: Coulston can reconfigure his desk into the embedded workstation pictured here.

Coulston says his workspace must function as a “typical office desk” 80 percent of the time and electronics station 20 percent of the time.

It must do this while maintaining some semblance of being presentable—my wife shares a desk in the same space. The foundation of my workstation is a recycled desk with a heavy plywood backing on which I attached shelving. Being a bit clumsy, I’ve tried to screw down anything that could be knocked over—speakers, lights, bulletin board, power strip, cable modem, and routers.

The head of a university department has different needs in a workspace than does an electronics designer. So how does Coulston make his single office desk suffice for both his professional and personal interests? It’s definitely not a messy solution.

My role as department chair and professor means that I spend a lot time grading, writing, and planning. For this work, there is no substitute for uncluttered square footage—getting all the equipment off the working surface. However, when it’s time to play with the circuits, I need to easily reconfigure this space.

I have found organization to be key to successfully realize this goal. Common parts are organized in a parts case, parts for each project are put in their own bag, the active project is stored in the top draw, frequently used tools, jumper wires, and DMM are stored in the next draw. All other equipment is stored in a nearby closet.

I’ve looked at some of the professional-looking workspaces in Circuit Cellar and must admit that I am a bit jealous. However, when it comes to operating under the constraints of a busy professional life, I have found that my reconfigurable space is a practical compromise.

To learn more about Coulston and his technical interests, check out his Member Profile.

Chris Coulston

Chris Coulston

Q&A: Embedded Systems Training Expert

Professional engineer Jason Long worked as an embedded systems designer for more than a decade. In 2010 he founded Engenuics Technologies. Jason lives in Victoria, BC, where he continues growing his company alongside the MicroProcessor Group (MPG) embedded systems hardware teaching program he developed in 2000.

 

CIRCUIT CELLAR: In 2010 you founded your company Engenuics Technologies (www.engenuics.com) based on the success of the MicroProcessorGroup (MPG) program. Give us a little background. How did the MPG begin?

JASON: MPG started way back in 2000 at the University of Calgary when I was doing my undergraduate studies. I figured out that embedded systems was exactly what I wanted to do, but struggled to find enough hands-on learning in the core curriculum programs to satisfy this new appetite. I was involved in the university’s Institute of Electrical and Electronics Engineers (IEEE) student branch, where someone handed me my first Microchip Technology PIC microcontroller and ran a few lunchtime tutorials about getting it up and running. I wanted more, and so did other people.

Jason Long

Jason Long

I was also very aware that I needed to drastically improve my personal confidence and my ability to speak in public if I was going to have any luck with a career outside of a cubicle, let alone survive an interview to get a job in the first place. The combination of these two things was the perfect excuse/opportunity to start up the MPG to ensure I kept learning by being accountable to teach people new stuff each week, but also to gain the experience of delivering those presentations.

I was blown away when there were almost 30 people at the first MPG meeting, but I was ready. Two things became very clear very quickly. The first was that, to be able to teach, you must achieve a whole new level of mastery about your subject, but it was also okay to say, “I don’t know” and find out for next week. The second was that I could, in fact, get my nerves under control as long as I was prepared and didn’t try to do too much. I’m still nervous every time I start a lecture, even 14 years later, but now I know how to use those nerves! The best part was that people really appreciated what I was doing and perhaps were a bit more tolerant since MPG is free. I found a love for teaching that I didn’t expect, nor did I get how rewarding the endeavor would be.

When I was wrapping up the ninth year of the program, I considered giving it one more year and then calling it quits. I took a moment to look back at what the program was when I started and where it had come to—it had indeed evolved a lot, and I figured I had put in about 2,000 h by this point. It seemed like a waste to throw in the towel. I also looked at the relationships that had come from the program, both personally and professionally, and realized that the majority of my career and who I had become professionally had really been defined by my work with MPG. But the program—even though it was still just in Calgary—was too big to keep as a side project. I had $10,000 in inventory to support the development boards, and although all monies stayed in the program, there were thousands of dollars exchanging hands. This was a business waiting to happen, though I had never thought of myself as an entrepreneur. I was just doing stuff I loved.

This ARM-based development board is made by Jason’s company, Engenuics Technologies.

This ARM-based development board is made by Jason’s company, Engenuics Technologies.

Around the same time I discovered SparkFun Electronics, and more importantly, I discovered the story of how the company got started by Nathan Seidie. That story begins almost exactly how MPG began, but clearly Nathan is a lot smarter than I am and has built an amazing company in the same time it took me to get to this point. I feel quite disappointed when I think about it that way, but thankfully I don’t think it’s too late to do what I should have done a long time ago. I hope to meet Nathan one day, but even if I don’t, I consider him a mentor and his story provides validation that the MPG platform and community may be able to grow and be sustainable.

I think MPG/Engenuics Technologies can find similar success as SparkFun. We can do that without ever having to compete against SparkFun because what we do is unique enough. There might be a bit of overlap, but I’m always going to try to complement what SparkFun does rather than compete against it. We simply become another resource to feed the voracious and infinite appetite for information from students, hobbyists, and engineers. Win-win is always the way to go.

I decided I should grow the program instead of ending it, so I started Engenuics Technologies, which would be built on the decade of MPG experience plus the decade of embedded design experience I had from the industry. It seemed like a pretty solid foundation on which to start a company! Surely I could promote all of the content and find students of the same mindset I was in when I started MPG? They could lead the program at different universities and develop those infinitely valuable communication and leadership skills that MPG fosters, except they’d have the advantage of not having to put in hundreds of hours to write all of the material. Even if groups of people weren’t playing with MPG, individuals could make use of the technical resource on their own and we could have a solid online community. I also wanted to keep students engaged beyond the single year of their engineer degrees in which MPG existed.

CIRCUIT CELLAR: What other products/services does Engenuics Technologies provide?

JASON: I describe Engenuics Technologies as a four-tier company as there are three significant aspects of the business in addition to MPG. The main purpose of the company is to fill a gap in the industry for specific training in embedded systems. There is very little formal training to be found for low-to-mid-level embedded hardware and firmware development and quality/value is often hit or miss. From teaching for 10 years while being an embedded designer for the same amount of time, I felt like I had the right skills to create great training. I had already created a LabVIEW course that I delivered internally for a company while I worked there, and people were blown away by the quality and content. I saw a huge need to develop embedded-specific training to help new graduates transition to the industry as well as junior engineers who were lacking in some fundamental engineering knowledge.

We have an embedded boot camp course that is about 20% hardware and 80% firmware focused, which I think is essential for new engineering graduates getting into embedded design. Though the course is based specifically on a Cortex-M3 development board, we ensure that we focus on how to learn a processor so the knowledge can be applied to any platform.

Engenuics Technologies has several courses now and we continue to offer those periodically though never as often as we would like, as we’ve become too busy with the other parts of the company. We finally got an office last August with an onsite training room, which makes the logistics much easier, and we’re ramping up the frequency of the programs we offer.

CIRCUIT CELLAR: You earned your BSEE from the University of Calgary in 2002. Can you describe any of the projects you’ve worked while you were there?

JASON: The professors at the U of C were a phenomenal bunch and it was a privilege to get to know them and work with them during my undergraduate studies. I remain in contact with many of them, and several are very good friends. Aside from blinking some LEDs on breadboards, the first complicated device I built was an attempt at the IEEE Micromouse competition. That proved to be a little much and my robot never did do anything beyond go forward, sense a wall, and then back up.

While studying at the University of Calgary, some of Jason’s first embedded designs included a programmable phase-locked loop project, a robot built for an IEEE Micromouse competition, an MPG dev board, and a binary clock.

While studying at the University of Calgary, some of Jason’s first embedded designs included a programmable phase-locked loop project, a robot built for an IEEE Micromouse competition, an MPG dev board, and a binary clock.

I originally thought I would base MPG around building robots, but that proved impossible due to cost. Building a robot is still on my bucket list. I’ll likely get there once my two boys are old enough to want to build robots. I continue to fantasize about building an autonomous quadcopter that can deliver beer. I better get busy on that before its commonplace!

Our IEEE student branch had a Protel 99 SE license and somehow I learned how to design PCBs. The first board I designed was a binary clock that I still use. I then did a PIC programmer and later I built a combined development board and programmer for MPG.

I also designed the PCB for our fourth-year Capstone design project, which initially was a very boring implementation of a phase-locked loop, but became a lot more fun when I decided to make it programmable with a keypad and an LCD. I brought all these things to my BW Technologies job interview and proudly showed them off. For any students reading this, by the way, landing your first engineering job is probably 5% technical, 10% GPA, and 85% enthusiasm and demonstrated interest and achievement. It’s really boring to interview someone who has done nothing extracurricular.

CIRCUIT CELLAR: How long have you been designing embedded systems? When did you become interested?

JASON: My dad was a high school science teacher and my mom was a nurse, so I didn’t have a lot of technical influence growing up. I loved talking physics with my dad, and I’m one of the few engineers who can cook (thank you, mom).

Aside from really liking LEGO and dismantling anything electronic (without ever a hope of putting it back together but always wondering what all those funny looking components did), I barely demonstrated any interest in EE when I was young. But somehow I figured out in grade 12 that EE was probably what I should study at university.

I’m sure I still had visions of being a video game designer, but that nagging interest in learning what those funny components did steered me to EE instead of computer science. It wasn’t until my second year at university when someone gave me my first PIC microcontroller that I really knew that embedded was where I needed to be. That someone was a student named Sean Hum, a brilliant guy who is now an associate professor at the University of Toronto.

CIRCUIT CELLAR: Which new technologies excite you?

JASON: I particularly like the 2.4-GHz radio technologies that hold the potential to really make our environment interactive and intelligent. I think the world needs more intelligence to address the wasteful nature of what we have become whether it is by actively doing something like turning the lights or heat off when we’re not around, or by simply making us more aware of our surroundings. I love ANT+ and am just getting into BLE—obviously, smartphone integration will be critical.

I think technology will drive change in education and I hope to see (and perhaps be a driving force behind) a more cohesive existence between academics and the industry. I hope MPG becomes a model to the industry of what can be achieved with not a lot of financial resources, but has immense payback for employees who become mentors and students who can connect with the industry much earlier and thus get more from their degree programs and graduate with substantially higher capabilities.

You can read the entire interview in Circuit Cellar 289 (August 2014).

New Dual Step-Down Regulator

Linear Technology recently announced an addition to its family of power regulator solutions. The LTC3622 is a dual step-down regulator in a small 3 × 4 mm package that provides two independently configurable 1-A outputs operating from a 2.7 to 17 V input. External voltage divider networks define the two output voltages or alternatively a range of fixed output voltage versions result in a lower component count. The input voltage range makes it suitable for operation from single or multiple lithium cells or from a vehicular supply.ltc3622-Linear

The regulator can operate in Burst mode to give highest efficiency at light loads or Pulse-Skipping mode to give lower ripple noise. The system clock can be synchronized to an external source to help to reduce system noise bandwidth.

Main Features:

  •  Dual step-down outputs: 1 A per channel
  •  VIN range: 2.7 to 17 V
  •  VOUT range: 0.6 V to VIN
  •  Up to 95% efficiency
  •  No-load IQ = 5 μA (both channels enabled)  < 4 μA (one channel enabled)
  •  High efficiency, low dropout operation (100% duty cycle)
  •  Constant frequency (1 MHz/2.25 MHz) with external synchronization
  •  ±1% output voltage accuracy
  •  Current mode operation improves line and load transient response
  •  Phase shift programmable with external clock
  •  Selectable current limit
  •  Internal compensation and soft-start
  •  Compact 14-pin DFN (3 mm × 4 mm) package

The regulator is available now with a per-unit cost starting at $3.75 for orders of 1,000 units.

[Source: Linear Technology]

24-Channel Digital I/O Interface for Arduino & Compatibles

SCIDYNE Corp. recently expanded its product line by developing a digital I/O interface for Arduino hardware. The DIO24-ARD makes it easy to connect to solid-state I/O racks, switches, relays, LEDs, and many other commonly used peripheral devices. Target applications include industrial control systems, robotics, IoT, security, and education.Scidyne

The board provides 24 nonisolated I/O channels across three 8-bit ports. Each channel’s direction can be individually configured as either an Input or Output using standard SPI library functions. Outputs are capable of sinking 85 mA at 5 V. External devices attach by means of a 50 position ribbon-cable style header.

The DIO24-ARD features stack-through connectors with long-leads allowing systems to be built around multiple Arduino shields. It costs $38.

[Source: SCIDYNE Corp.]