It’s no secret that the Arduino development board has changed the way we look at working with electronics. All over the world, the little board has enabled millions of engineers, students, artists, and makers to get electronics projects up and going. We recently traveled to DotDotDot in Milan, Italy, to chat with Arduino codeveloper Massimo Banzi, who talked about the history of Arduino, the importance of makerspaces, and more.
Ayse K. Coskun is an associate professor in the Electrical and Computer Engineering Department at Boston University, where she is working on 3-D stacked architectures. She recently sat for an interview about her background, work, and research in the areas of 3-D stacked architectures and green computing.
About five years ago, a small group of enthusiast designers led by Eben Upton launched a small, inexpensive computer that looked nothing like a normal computer. The bare green PCB board appealed to makers and hackers and the option to connect a keyboard and screen appealed to traditional computer nerds. Today, the Raspberry Pi is the best-selling personal computer in the United Kingdom.
Circuit Cellar recently visited Cambridge, England, to interview Upton about his work at the Raspberry Pi Foundation and more. Check it out.
We first met London-based engineer Saar Drimer in December 2015. At that time, his was running Boldport—a hardware and prototyping consultancy that specializes in circuit boards—from a workspace was in one of the characteristic arches underneath London Bridge Station. A lot has changed since then. Today, Drimer has a new workspace and he is running Boldport Club, which is a monthly electronics hardware subscription service. We recently met up with him to discuss his work and newest endeavors.
“The big change is the club I started early this year,” Drimer explained. “I posted my initial ideas online and the response was very promising, around 170 members signed up in the first month.”
When you talk about a startup, you likely envision bearded hipsters drinking fancy coffee at their expensive Macs. But not all startups are cut from the same cloth. Consider the following case. We recently met with a small team of talented long-time engineers in Madrid that is swimming against the tide. After working for many years in the electronics design industry, the engineers now innovating secure hardware products at a startup with big ideas and lofty goals.
Engineer and author Robert Lacoste has been designing and innovating for more than two decades. Fortunately for us, Robert is also an excellent writer who regularly publishes Circuit Cellar articles on the “dark” and difficult side of engineering. Over the years, he has taught us about topics ranging from direct digital synthesis to RF mixers to bipolar transistor biasing.
This week, Robert gives us a tour of his consulting company, Alciom, which is based just outside of Paris. He also talks about his electronics equipment and his love for difficult projects.
Want to see what it’s like buying electronics (e.g., Arduino, displays, and general components) in Mumbai? Circuit Cellar correspondent and videographer Wisse Hettinga joins engineer Nishant Mittal on a tour of Lamington Road, Mumbai, India. This street is famous for the many electronics shops. You can find virtually any component you can think of.
“Together with Nishan Mittal, we go inside Lamington Road and discover one of the biggest electronics markets in the world,” Hettinga says. In this video they search for a good price on an Arduino.
Dr. Max Ortiz Catalan is Research Director at Integrum AB, a medical device company based in Molndal, Sweden. Wisse Hettinga recently interviewed him about his work in the field of prosthetic design and biomedical systems.
As an electrical engineer, your first focus is to create new technology or to bring a new schematic design come to life. Dr. Max Ortiz Catalan is taking this concept much further. His research and work is enabling people to really start a new life!
People without an upper limb often find it difficult to manage tasks due to the limitations of prostheses. Dr. Catalan’s research at Chalmers University of Technology and Sahlgrenska University Hospital in Gothenburg, Sweden, focuses on the use of osseointegrated implants and a direct electronic connection between the nervous system and a prosthetic hand. People can control the prosthesis just like you control your hand, and they are able to sense forces as well. The results are impressive. The first patient received his implant three years ago and is successfully using it today. And more patients will be treated this year. I recently interviewed Dr. Catalan about his work. I trust this interview will inspire seasoned and novice engineers alike.—Wisse Hettinga
HETTINGA: What led you to this field of research?
CATALAN: I was always interested in working on robotics and the medical field. After my bachelor’s in electronics, my first job was in the manufacturing industry, but I soon realized that I was more interested in research and the development of technology. So I left that job to go back to school and do a master’s in Complex Adaptive System. I also took some additional courses in biomedical engineering and then continued working in this field where I did my doctoral work.
HETTINGA: I was surprised you did not mention the word “robot” once in your TEDx presentation (“Bionic Limbs Integrated to Bone, Nerves, and Muscles”)? Was that coincidence or on purpose?
CATALAN: That was coincidence, you can call a prosthesis a “robotic device” or “robotic prosthesis.” When you talk about a “robot,” you often see it as an independent entity. In this case, the robotic arm is fully controlled by the human so it makes more sense to talk about bionics or biomechatronics.
HETTINGA: What will be the next field of research for you?
CATALAN: The next step for us is the restoration of the sense of touch and proprioception via direct nerve stimulation, or “neurostimulation.” We have developed an embedded control system for running all the signal processing and machine learning algorithms, but it also contains a neurostimulation unit that we use to elicit sensations in the patient that are perceived as arising from the missing limb. The patients will start using this system in their daily life this year.
HETTINGA: You are connecting the controls of the prosthesis with nerves. How do you connect a wire to a nerve?
CATALAN: There are a variety of neural interfaces (or electrodes) which can be used to connect with the nerves. The most invasive and selective neural interfaces suffer from long-term instability. In our case we decided to go for a cuff electrode, which is considered as a extra-neural interface since it does not penetrate the blood-nerve barrier and is well tolerated by the body for long periods of time, while also remaining functional.
HETTINGA: Can you explain how the nerve signals are transferred into processable electric signals?
CATALAN: Electricity travels within the body in the form of ions and the variations in electric potentials, or motor action potentials for control purposes. They are transduced into electrons by the electrodes so the signals can be finally amplified by analog electronics and then decoded on the digital side to reproduce motor volition by the prosthesis.
HETTINGA: What is the signal strength?
CATALAN: Nerve signals (ENG) are in the order of microvolts and muscle signals (EMG) in the order of millivolts.
HETTINGA: What technologies are you using to cancel out signal noise?
CATALAN: We use low-noise precision amplifiers and active filtering for the initial signal conditioning, then we can use adaptive filters implemented in software if necessary.
HETTINGA: How do you protect the signals being disturbed by external sources or EM signals?
CATALAN: Since we are using implanted electrodes, we use the body as a shielding, as well as the titanium implant and the electronics housing. This shielding becomes part of the amplifier’s reference so it is rejected as common noise.
HETTINGA: How are the signals transferred from the nerves to the prosthesis?
CATALAN: The signals from nerves and muscles are transferred via the osseointegrated implant to reach the prosthesis where they are amplified and processed. In a similar ways, signals coming from sensors in the prosthesis are sent into the body to stimulate the neural pathways that used to be connected to the biological sensors in the missing hand. Osseointegration is the key difference between our work and previous approaches.
HETTINGA: What sensors technologies are you using in the prosthetic hand?
CATALAN: At this point it is rather straightforward with strain gauges and FSRs (Force Sensitive Resistor), but on research prostheses, motors are normally instrumented as well so we can infer joint angles.
This interview appears in Circuit Cellar 307 February.
Mitch Altman is an inventor (TV-B-Gone), hacker and traveler whose ideas will inspire many of us to join a hackerspace and get creative with the design community. Circuit Cellar recently met up with Altman at FabLab Berlin, Germany. Altman talks about hacking and presents a new synthesizer, which is a board with an Arduino, sound amplifier, and keyboard-shaped pads to play music.
Saar Drimer (PhD, Cambridge) runs Boldport, a London-based hardware and prototyping consultancy that specializes in circuit boards. Wisse Hettinga recently met with Drimer to discuss PCB design, electronics craftsmanship, and his various engineering projects.
The Art of Electronics is a book that’s well-known by many electronic engineers all over the world. Written by Horowitz and Hill, the first edition was published in 1980 and recently, in 2015, a third edition was released. Over the past 35 years, the book has been an inspiration and resource for many engineers eager to learn about the art of designing with electronics. But there is also a real art of electronics. To discover what that is, I traveled to London to meet up with Saar Drimer. His workplace was in one of the characteristic arches underneath London Bridge Station. With the constant rumble of the trains arriving and pulling out of the station in the background, he showed me some of his work.
SOMETHING COMPLETELY DIFFERENT
Drimer’s designs are completely different from what we usually see on PCBs. Where most of our designs end up as small rectangles with only a few holes for the assembly screws, his boards take different shapes. Some are swirly, sometimes animal-like. At other times, he integrates components right into the board in special holes, as you can see in his Tiny Engineer Superhero Emergency Kit. Often there is no straight copper line to be found; they go all over the place and are a vital part of the total design.
A PCB designed by Drimer asks for exposure and can be interesting for art’s sake only, but also for marketing purposes where drawing attention and presenting a surprise is required. One of his designs even features in the women’s magazine Marie Claire!
DESIGNING THE OTHER WAY AROUND
Where many of us try to put all the PCB and wiring in a (mostly) gray box and leave it out of sight, Drimer is doing exactly the opposite: he is trying to expose it. His end product is the PCB and that is where his art comes into the picture—in many exciting formats. In many ways, Saar is an engineer like many of us. He is extremely knowledgeable about electronics and designing. But when it comes to the latter, he is using unorthodox methods. Where we start with the schematics, Drimer starts with the form and shape of the final PCB—basically, he designs the other way around!
Working and designing in the opposite direction is not easy with existing PCB CAD programs like Eagle or Altium. They all start with a schematic and are using component libraries routing the final layout in the most effective or smallest footprint PCB. Their rigid, straightforward approach is excellent when designing for just another rectangle PCB. But if you want new and creative designs, you need to think of a different way of working and using other tools. If you want to change the way of thinking and designing, you need to be able to use free forms and the routing cannot be left to the CAD program. And that is exactly what Drimer is doing.
THE CRAFTSMAN’S TOOL
To be able to start with a different type of design, Drimer was left with no choice but to start developing his own PCB CAD design program. Unlike most of us who call ourselves “engineer,” Drimer calls himself ”craftsman”—and as a true craftsmen, he makes his own tools. PCBmodE is Drimer’s custom PCB CAD program. The “mod” in PCBmodE has a double meaning, Drimer explained. “The first is short for ‘modern’ in contrast to tired, old EDA tools. The second is a play on the familiar ‘modifications,’ or ‘mods,’ done to imperfect PCBs. Call it ‘PCB mode’ or ‘PCB mod E’, whichever you prefer,” he said.
PCBmodE is a PCB design Python script that creates an SVG from JSON input files. It then creates Gerber (the standard software to describe the PCB images: copper layers, soldering mask, legend, etc.) and Excellon files for manufacturing. With no graphical interface, PCBmodE enables you to place any arbitrary shape on any layer because it is natively vector-based. Most of the design is done in a text editor with viewing and some editing (routing) completed with Inkscape. (Inkscape is a professional vector graphics editor for Windows, Mac OS X, and Linux. It’s free and open source.) On his website, Drimer explains how to work with the program.
“PCBmodE was originally conceived as a tool that enables the designer to precisely define and position design elements in a text file, and not through a GUI. For practical reasons, PCBmodE does not have a GUI of its own, and uses an unmodified Inkscape for visual representation and some editing that cannot practically be done textually,” said Drimer.
A typical PCBmodE design workflow is as follows:
- Edit JSON files with a text editor
- “Compile” the board using PCBmodE
- View the generated SVG in Inkscape
- Make modifications in Inkscape
- Extract changes using PCBmodE
- Back to step 1 or step 2
- Generate production files using PCBmodE
If you want to give PCBmodE a try, simply download it at www.pcbmode.com. It works with Linux, but Drimer is interested in results on other OS platforms as well. For starters, a “hello solder” design is currently available.
THE CRAFTSMAN’S WORK
Examples of Drimer’s work are posted on his website, www.boldport.com. I especially like the Tiny Engineer Superhero Emergency Kit’ design where the components are integrated into the PCB itself resulting in a very flat design. You will also notice he is not using straight lines and angles for the traces. It is more of a pencil drawing; the traces flow along the lines of the PCB and components.
You might ask why on earth someone would put so much effort into all of this? Don’t ask! But, if you like, here are a few answers. First, because it is an art. Second, it is Drimer’s full-time job and he hopes to expand the business. And third, working differently from the norm tends to generate fresh ideas and exciting solutions—and that is what we need more of.
This article appears in Circuit Cellar 306 (January 2016).
Rich Legrand founded Charmed Labs in 2002 to develop and sell innovative robotics-related designs, including the Xport Robot Kit, the Qwerk robot controller, the GigaPan robotic camera mount, and the Pixy vision sensor. He recently told us about his background, passion for robotics, and interest in open-source hardware.
RICH: Back in 1982 when I was 12, one of my older brother’s friends was what they called a “whiz kid.” I would show up uninvited at his place because he was always creating something new, and he didn’t treat me like a snotty-nosed kid (which I was). On one particular afternoon he had disassembled a Big Trak toy (remember those?) and connected it to his Atari 800, so the Atari could control its movements. He wrote a simple BASIC program to read the joystick movements and translate them to Big Trak movements. You could then hit the return key and the Atari would play back the motions you just made. There were relays clicking and LEDs flashing, and the Big Trak did exactly what you told it to do. I had never seen a computer do this before, and I was absolutely amazed. I wanted to learn as much as I could about electronics after that. And I’m still learning, of course.
CIRCUIT CELLAR: You studied electrical engineering at both Rice University and North Carolina State University. Why electrical engineering?
RICH: I think it goes back to when I was 12 and trying to learn more about robotics. With a limited budget, it was largely a question of what I get my hands on. Back then you could go into Radio Shack and buy a handful of 7400 series parts and create something simple, but pretty amazing. Forrest Mims’s books (also available at Radio Shack) were full of inspiring circuit designs. And Steve Ciarcia’s “Circuit Cellar” column in Byte magazine focused on seat-of-the-pants electronics projects you could build yourself. The only tools you needed were a soldering iron, a voltmeter, and a logic probe. I think young people today see a similar landscape where it’s easier to get involved in electrical engineering than say mechanical engineering (although 3-D printing might change this). The Internet is full of source material and the hardware (computers, microcontrollers, power supplies, etc.) is lower-cost and easier to find. The Arduino is a good example of this. It has its own ecosystem from which you can launch practically any project or idea.
CIRCUIT CELLAR: Photography factors in a lot of your work and work history. Is photography a passion of yours?
RICH: I don’t think so, but I enjoy photography. Image processing, image understanding, machine vision—the idea that you can extract useful information from a digital image with a piece of software, an algorithm. It’s a cool idea to me because you can have multiple vision algorithms and effectively have several sensors in one package. Or in the case of Gigapan, being able to create a gigapixel imager from a fairly low-cost point-and-shoot camera, some motors, and customized photo stitching software. I’m a hardware guy at heart, but hardware tends to be expensive. Combining inexpensive hardware with software to create something that’s lower-cost—it sounds like a pretty niche idea, but these are the projects that I seem to fall for over and over again. Working on these projects is what I really enjoy.
CIRCUIT CELLAR: Prior to your current gig at Charmed Labs, you were with Gigapan Systems, which you co-founded. Tell us about how you came to launch Gigapan.
RICH: Gigapan is robotic camera mount that allows practically anyone with a digital camera to make high-resolution panoramas. The basic idea is that you take a camera with high resolution but narrow field-of-view (high-zoom) to capture a mosaic of pictures that can be later stitched together with software to form a much larger, highly-detailed panorama of the subject, whether it’s the Grand Canyon or the cockpit of the Space Shuttle. This technique is used by the Mars rovers, so it’s not surprising that a NASA engineer (Randy Sargent) first conceived Gigapan. Charmed Labs got a chance to bid on the hardware, and we designed and manufactured the first Gigapan units as part of a public beta program. (The beta was funded by Carnegie Mellon University through donations from NASA and Google.) The beta garnered enough attention to get investors and start a company to focus on Gigapan, which we did. We were on CNN, we were mentioned on Jay Leno. It was a fun and exciting time!
CIRCUIT CELLAR: In a 2004 article, “Closed-Loop Motion Control for Mobile Robotics“ (Circuit Cellar 169), you introduced us to your first product, the Xport. How did you come to design the Xport?
RICH: When the Gameboy Advance was announced back in 1999, I thought it was a perfect robot platform. It had a color LCD and a powerful 32-bit processor, it was optimized for battery power, and it was low-cost. The pitch went something like: “For $40 you can buy a cartridge for your Gameboy that allows you to play a game. For $99 you can buy a cartridge with motors and sensors that turns your Gameboy into a robot.” So the Gameboy becomes the “brains” of the robot if you will. I didn’t know what the robot would do exactly, other than be cool and robot-like, and I didn’t know how to land a consumer electronics product on the shelves of Toys “R” Us, so I tackled some of the bigger technical problems instead, like how to turn the Gameboy into an embedded system with the required I/O for robotics. I ordered a Gameboy from Japan through eBay prior to the US release and reverse-engineered the cartridge port. The first “Xport” prototype was working not long after the first Gameboys showed up in US stores, so that was pretty cool. It was a simple circuit board that plugged into the Gamboy’s cartridge port. It had flash for program storage and an FPGA for programmable I/O. The Xport seemed like an interesting product by itself, so I decided to sell it. I quit my job as a software engineer and started Charmed Labs.
CIRCUIT CELLAR: Tell us about the Xport Botball Controller (XBC).
RICH: The Xport turned the Gameboy into an embedded system with lots of I/O, but my real goal was to make a robot. So I added more electronics around the Xport for motor control, sensor inputs, a simple vision system, even Bluetooth. I sold it online for a while before the folks at Botball expressed interest in using it for their robot competition, which is geared for middle school and high school students. Building a robot out of a Gameboy was a compelling idea, especially for kids, and tens of thousands of students used the XBC to learn about engineering—that was really great. I never got the Gameboy robot on the shelves of Toys “R” Us, but it was a really happy ending to the project.
CIRCUIT CELLAR: Charmed Labs collaborated with the Carnegie Mellon CREATE Lab on the Qwerk robot controller. How did you end up collaborating with CMU?
RICH: I met Illah Nourbakhsh who runs the CREATE lab at a robot competition back when he was a grad student. His lab’s Telepresence Robotics Kit (TeRK) was created in part to address the falling rate of computer science graduates in the US. The idea was to create a curriculum that featured robotics to help attract more students to the field. Qwerk was an embedded Linux system that allowed you make a telepresence robot easily. You could literally plug in some motors, a webcam, and a battery, and fire up a web browser and become “telepresent” through the robot. We designed and manufactured Qwerk for a couple years before we licensed it.
CIRCUIT CELLAR: Pixy is a cool vision sensor for robotics that you can teach to track objects. What was the impetus for that design?
RICH: Pixy is actually the fifth version of the CMUcam. The first CMUcam was invented at Carnegie Mellon by Anthony Rowe back in 2000 when he was a graduate student. I got involved on a bit of a lark. NXP Semiconductors had just announced a processor that looked like an good fit for a low-cost vision sensor, so I sent Anthony a heads-up, that’s all. He was looking for someone to help with the next version of CMUcam, so it was a happy coincidence.
CIRCUIT CELLAR: You launched Pixy in 2013 on Kickstarter. Would you recommend Kickstarter to Circuit Cellar readers who are thinking of launching a hardware product?
RICH: Before crowdfunding was a thing, you either had to self-fund or convince a few investors to contribute a decent amount of cash based on the premise that you had a good idea. And the investors typically didn’t have your background or perspective, so it was usually a difficult sell. With crowdfunding, a couple hundred people with similar backgrounds and perspectives contribute $50 (or so) in exchange for becoming the very first customers. It’s an easier path I think, and it’s a great fit for products like Pixy that have a limited but enthusiastic audience. I think of crowdfunding as a cost-effective marketing strategy. Sites like Kickstarter get huge amounts of traffic, and getting your idea in front of such a large audience is usually expensive—cost-prohibitive in my case. It also answers two important questions for hardware makers: Are enough people interested in this thing to make it worthwhile? And if it is worthwhile, how many should I make?
But I really didn’t think many people would be interested in a vision sensor for hobbyist robotics, so when faced with the task of creating a Kickstarter for Pixy, I thought of lots of excuses not to move forward with it. Case in point—if your Kickstarter campaign fails, it’s public Internet knowledge. (Yikes!) But I’m always telling my boys that you learn more from your mistakes than from your successes, so it seemed pretty lame that I was dragging my heals on the Kickstarter thing because I wanted to avoid potential embarrassment. I eventually got the campaign launched, and it was a success, and Pixy got a chance to see the light of day, so that was good. It was a lot of work, and it was psychologically exhausting, but it was really fun to see folks excited about your idea. I’d totally do it again though, and I’d like to crowdfund my next project.
CIRCUIT CELLAR: Can you tell us about one or two of the more interesting projects you’ve seen featuring Pixy?
RICH: Ben Heck used Pixy in a couple of his episodes of the Ben Heck Show (www.element14.com/community/community/experts/benheck). He used Pixy to create a camera that can automatically track what he’s filming. And Microsoft used Pixy for an Windows 10 demo that played air hockey IR-Lock (www.irlock.com) is a small company that launched a successful Kickstarter campaign that featured Pixy as a beacon detector for use in autonomous drones. All of these projects have a high fun-factor, which I really enjoy seeing.
CIRCUIT CELLAR: What’s next for Charmed Labs?
RICH: I’ll tell you about one of my crazier ideas. My wife gets on my case every holiday season to hang lights on the house. It wouldn’t be that bad, except our next-door neighbors go all-out. They hang lights on every available surface of their house—think Griswolds from the Christmas Vacation movie. So anything I do to our house looks pretty sad by comparison. I’m competitive. But I had the idea that if I created a computer-controlled light show that’s synchronized to music, it might be a good face-saving technology, a way to possibly one-up the neighbors, because that’s what it’s all about, right? (Ha!) So I’ve been working on an easy-to-set-up and low-cost way to make your own holiday light show. It’s way outside of my robotics wheelhouse. I’m learning about high-voltage electronics and UL requirements, and there’s a decent chance it won’t be cost-competitive, or even work, but my hope is to launch a crowdfunding campaign in the next year or so.
CIRCUIT CELLAR: What are your thoughts on the future of open-source hardware?
RICH: We can probably thank the Arduino folks because before they came along, very few were talking about open hardware. They showed that you can fully open-source a design (including the hardware) and still be successful. Pixy was my first open hardware project and I must admit that I was a little nervous moving forward with it, but open hardware principles have definitely helped us. More people are using Pixy because it’s fully open. If you’re interested in licensing your software or firmware, open hardware is an effective marketing strategy, so I don’t think it’s about “giving it all away” as some might assume. That is, you can still offer closed-source licenses to customers that want to use your software, but not open-source their customizations. I’ve always liked the idea of open vs. proprietary, and I’ve learned plenty from fellow engineers who choose to share instead of lock things down. It’s great for innovation.
On a different robot, a flapping winged ornithopter, we had this PC104 computer running matlab as the controller. It probably weighed about 2 pounds, which forced us to build a huge wingspan – almost 6 feet. We dreamed about adding some machine vision to the platform as well. Having just built a vision-based robot for MIT’s MASLAB competition using an FPGA paired with an Arduino – the PC104 solution started to look pretty stupid to me. That was what really got me interested embedded work. FPGAs and Microcontrollers gave you an insane amount of computing power at comparatively minuscule power and weight footprints. And so died the PC104 standard.
This interview appears in Circuit Cellar 305 (December 2015).
In 2009, Andrew Meyer, an MIT-trained engineer and entrepreneur, co-founded LeafLabs, a Cambridge, MA-based R&D firm that designs “powerful physical computing devices for control and communication among smart machines (including humans).” We recently asked Andrew to tell us about his background, detail some of his most intriguing projects, tell us about his contributions to Project Ara, and share his thoughts on the future of electrical engineering.
CIRCUIT CELLAR: How did you become interested in electronics? Did you start at a young age?
ANDREW: Yes, actually, but I am not sure I really got anywhere fooling around as a kid. I had a deep love of remote control cars and airplanes in middle school. I was totally obsessed with figuring out how to build my own control radio. This was right before the rise of Google, and I scoured the net for info on circuits. In the end, I achieved a reasonable grasp on really simple RC type circuits but completely failed in figuring out the radio. Later in high school I took some courses at the local community college and built an AM radio and got into the math for the first time – j and omega and all that.
CIRCUIT CELLAR: What is Leaflabs? How did it start? Who comprises your team today?
ANDREW: LeafLabs is an R&D firm specializing in embedded and distributed systems. Projects start as solving specific problems for a client, but the idea is to turn those relationships into product opportunities. To me, that’s what separates R&D from consulting.
I started LeafLabs with a handful of friends in 2009. It was an all MIT cast of engineers, and it took four or five years before I understood how much we were holding ourselves back by not embracing some marketing and sales talent. The original concept was to try and design ICs that were optimized for running certain machine learning algorithms at low power. The idea was that smartphones might want to do speech to text some day without sending the audio off to the cloud. This was way too ambitious for a group of 22 year olds with no money.
Our second overly ambitious idea was to try and solve the “FPGA problem.” I’m still really passionate about this, but it too was too much for four kids in a basement to take a big bite off. The problem is that FPGAs vendors like Xilinx and Altera have loads of expertise in silicon, but great software is just not in their DNA. Imagine if x86 never published their instruction set. What if Intel insisted on owning not just the processors, but the languages, compilers, libraries, IDEs, debuggers, operating systems, and the rest of it? Would we ever have gotten to Linux? What about Python? FPGAs have enormous potential to surpass even the GPU as a completely standard technology in computer systems. There should some gate fabric in my phone. The development tools just suck, suck, suck. If any FPGA executives are reading this: Please open up your bitstream formats, the FSF and the rest of the community will get the ball rolling on an open toolchain that will far exceed what you guys are doing internally. You will change the world.
CIRCUIT CELLAR: How did the Maple microcontroller board come about?
ANDREW: Arduino was really starting to come up at the time. I had just left Analog, where we had been using the 32-bit Cortex M3. We started asking “Chips like the STM32 are clearly the way of the future, why on earth is Arduino using a chip from the ‘90s?” Perry, another LeafLabs founder, was really passionate about this. ARM is taking over the world, the community deserves a product that is as easy to use as Arduino, but built on top of modern technology.
CIRCUIT CELLAR: Can you give a general overview of your involvement with Project Ara?
ANDREW: We got into Ara at the beginning as subcontractors to the company that was leading a lot of the engineering, NK Labs. Since then our role has expanded quite a bit, but we are still focused on software and firmware development. Everyone understood that Ara was going to require a lot of firmware and FPGA work, and so we were a natural choice to get involved. One of the first Ara prototypes actually used the Maple software library, libmaple, and had eight FPGAs in it! For your readers that are interested in Ara, please to check out projectara.com and https://github.com/projectara/greybus/.
LeafLabs is focused on firmware development. What’s really exciting to me about the project is the technology under the hood. Basically, what we have done is built a network on a PCB. The first big problem with embedded linux devices is that they are completely centered around the SoC. Change the SoC and you are in for ton of software development, for instance, to bring your display driver back to life. Similarly, changes to the design, such as incorporating a faster Wi-Fi chip, might force you to change the SoC. This severe coupling between everything keeps designers from iterating. You have this attitude of “OK, no one touch this design for the next 5 years, we finally got it working.” If we have learned anything from SaaS and App companies it’s that quickly iterating and continuous deployment are key to great products. If your platform inhibits iteration, you have a big problem.
The other problem with embedded systems is that there are so many protocols! SDIO, USB, DSI, I2C, SPI, CSI, blah blah blah. Do we really need so many!? Think how much mileage we get out of TCP/IP. The protocol explosion just adds impedance to the entire design process, and forces engineers to be worrying about bits toggling on traces rather than customer facing features.
The technology being developed for Ara, called Greybus, solves both these problems. The centerpiece of our phone is a switch, and the display, Wi-Fi, audio, baseband, etc all hang off the switch as network devices. Even the processor is just another module hanging off this network. All modules speak the same “good enough” protocol called UniPro (Unified Protocol). The possibilities here are absolutely tantalizing. To learn more about Greybus, see here: https://github.com/projectara/greybus/.
CIRCUIT CELLAR: Can you define “minimalist data acquisition” for our readers? What is it and why does it interest you?
ANDREW: More and more fields, but particularly in neuroscience, are having to deal with outrageously huge real-time data sets. There are 100 billion neurons in the human brain. If we want to listen to just 1,000 of them, we are already talking about ~1 Gbps. Ed Boyden, a professor at MIT, asked us if we could build some hardware to help handle the torrent. Could we scale to 1 Tbps? Could we build something that researchers on a budget could actually afford and that mere mortals could use?
Willow is a hardware platform for capturing, storing, and processing neuroscience data at this scale. We had to be “minimalist” to keep costs down, and ensure our system is easy to use. Since we need to use an FPGA anyway to interface with a data source (like a bank of ADCs, or an array of image sensors), we thought, “Why not use the same chip for interfacing to storage?” With a single $150 FPGA and a couple of $200 SSD drives, we can record at 12 Gbps, put guarantees on throughput, and record for a couple of hours!
CIRCUIT CELLAR: What are you goals for LeafLabs for the next 6 to 12 months?
ANDREW: Including our superb remote contractors, our team is pushing 20. A year from now, it could be double that. This is a really tricky transition—where company culture really starts to solidify, where project management becomes a first-order problem, and where people’s careers are on the line. My first goal for LeafLabs is make sure we nail this transition and build off of a really solid foundation. Besides that, we are always looking for compelling new problems to work on and new markets to play in. Getting into neuroscience has been an absolute blast.
The complete interview appears in Circuit Cellar 298 (May 2015).
We met with Geoff Lees (Senior Vice President & General Manager of Microcontrollers, Freescale) at the 2015 Embedded World Show in Nuremberg, Germany. We asked him about the Internet of Things, the big changes on the embedded systems horizon, and what it takes to be a successful engineer.
CIRCUIT CELLAR: The Embedded World Show is one of the biggest that specifically focuses on embedded technologies, new products, and design. What makes this show special?
GEOFF: In Europe we go to the Electronica in Munich and also to this show. At Electronica, we meet up with our clients and distributors. This Embedded show has a much more technical focus. Here we meet with the individual designers and technical teams of our clients and see most in-depth technical discussions. At the Electronica show we talk business; here we talk more technology and what it can do for the client.
CIRCUIT CELLAR: Talking about individual engineers, we remember last year in your press conference you mentioned a focus on hobbyists. That’s quite remarkable for a company like Freescale. We also see there is a small “maker lab” in your booth at the show.
GEOFF: It is important to address makers and hobbyists for two reasons. First, there are the sheer numbers. At Maker Show in New York, you see there a 100,000 people showing up. At a show like this, it is 20,000 to 25,000. Here we see the engineering teams of companies. But what is interesting about the maker community is that individuals can have an idea or innovation, create and build the prototypes, but instead of having a company making this, they have the community and can even go to market.
CIRCUIT CELLAR: Sometimes we get the idea that the bigger companies are looking at the crowd-funding communities as part of—or as a replacement for—their own R&D activities. How does that work for a company like Freescale?
GEOFF: One thing that’s very clear in today’s world is speed. Sometimes an individual, with very little obstruction, can have speed that cannot be matched by companies—and someone who can respond or react to the requirements almost instantaneously has an advantage. There are so many of these. Finding and communicating with them is almost an impossible task. You really have to watch carefully. It is almost impossible to know where the next innovation is coming from.
CIRCUIT CELLAR: You call the Internet of Things, the Internet of Tomorrow?
GEOFF: The IoT is a very disruptive force. It started out as a buzz, but it is in the “nature” of microcontrollers to connect and to communicate. With new Wi-Fi concepts, low-power and IPv6 the road is clear for many new applications. To demonstrate the new technologies we have a “bigger than big” truck driving through the US. We put it in the parking lot of companies and demo not only our own products, but also their products as well as the solutions of their competitors. With a show you get the designers or marketing people. With the truck we also have CEOs and CTOs for a coffee—the guys who would not even consider visiting our website!
CIRCUIT CELLAR: But how will the IoT affect us?
GEOFF: I currently have eight apps on my phone that are all IoT controls, monitoring my house, solar panels, and vehicle. I expect that number will grow. Also, devices will talk to devices and create new independent controls. “Big Ass Fans” is a nice example of that. That company is making fans but is also playing a role in home automation. Their latest model fan talks to the NEST. Only a small difference in temperature can set the fan to work rather than your air conditioning, either by cooling down or circulating the hotter air downwards.
CIRCUIT CELLAR: Everyone knows that standards are key to making the IoT really happen. What role does Freescale have in this?
GEOFF: We joined up with the Thread Group. This initiative started with only eight companies, and that number has grown to 50 in five months, and now we see around 1,000 companies that look for information. If we see a growth from eight to 50 to 1,000, you know that there is a momentum which will result in new standards. The Thread Group uses existing (IEEE 8082.15.4) technologies and standards to build a new wireless mesh protocol that will enable to overcome the current limitations in wireless home automation. The Thread Networks will aim at the simple installation of new nodes and it can scale up to 250 and more devices in a single network. No company—whether you are Cisco or IBM or Oracle—has the power to set the standard on their own, maybe a part of it, but not all. This will go as usual, an initiative will gain critical mass, and then the momentum drives it through. This will all be about momentum.
The complete interview appears in Circuit Cellar 297 (April 2015).
Katherine J. Kuchenbecker is an Associate Professor in Mechanical Engineering and Applied Mechanics at the University of Pennsylvania, with a secondary appointment in Computer and Information Science. She directs the Penn Haptics Group, which is part of the General Robotics, Automation, Sensing, and Perception (GRASP) Laboratory. In this interview, she tells us about her research, which centers on the design and control of haptic interfaces for applications such as robot-assisted surgery, medical simulation, stroke rehabilitation, and personal computing.
CIRCUIT CELLAR: When did you first become interested in haptics and why did you decide to pursue it?
KATHERINE: I chose to become an engineer because I wanted to create technology that helps people. Several topics piqued my interest when I was pursuing my undergraduate degree in mechanical engineering at Stanford, including mechatronics, robotics, automotive engineering, product design, human-computer interaction, and medical devices. I was particularly excited about areas that involve human interaction with technology. Haptics is the perfect combination of these interests because it centers on human interaction with real, remote, or virtual objects, as well as robotic interaction with physical objects.
My first exposure to this field was a “haptic paddle” lab in a Stanford course on system dynamics, but that alone wouldn’t have been enough to make me fall in love with this field. Instead, it was conversations with Günter Niemeyer, the professor who advised me in my PhD at Stanford. I knew I wanted a doctorate so that I could become a faculty member myself, and I was inspired by the work he had done as an engineer at Intuitive Surgical, Inc., the maker of the da Vinci system for robotic surgery. Through my early research with Günter, I realized that it is incredibly satisfying to create computer-controlled electromechanical systems that enable the user to touch virtual objects or control a robot at a distance. I love demonstrating haptic systems because people make such great faces when they feel how the system responds to their movements. Another great benefit of studying haptics is that I get to work on a wide variety of applications that could potentially impact people in the near future: robotic surgery, medical training, stroke rehabilitation, personal robotics, and personal computing, to name a few.
CIRCUIT CELLAR: What is haptography? What are its benefits?
KATHERINE: I coined the term “haptography” (haptic photography) to proclaim an ambitious goal for haptics research: we should be able to capture and reproduce how surfaces feel with the same acuity that we can capture and reproduce how surfaces look.
When I entered the field of haptics in 2002, a lot of great research had been done on methods for letting a user feel a virtual three-dimensional shape through a stylus or thimble. Essentially, the user holds on to a handle attached to the end of a lightweight, back-drivable robot arm; the 3D Systems Touch device is the most recent haptic interface of this type. A computer measures the motion that the person makes and constantly outputs a three-dimensional force vector to give the user the illusion that they are touching the object shown on the screen. I was impressed with the haptics demonstrations I tried back in 2002, but I was also deeply disappointed with how the virtual surfaces felt. Everything was soft, squishy, and indistinct compared to how real objects feel. That’s one of the benefits of being new to a field; you’re not afraid to question the state of the art.
I started working to improve this situation as a doctoral student, helping invent a way to make hard virtual surfaces like wood and metal feel really hard and realistic. The key was understanding that the human haptic perceptual system keys in on transients instead of steady-state forces when judging hardness. I had to write a research statement to apply for faculty positions at the end of 2005, so I wrote all about haptography. Rather than trying to hand-program how various surfaces should feel, I wanted to make it all data driven. The idea is to use motion and force sensors to record everything a person feels when using a tool to touch a real surface. We then analyze the recorded data to make a model of how the surface responds when the tool moves in various ways. As with hardness, high-frequency vibration transients are also really important to human perception of texture, which is a big part of what makes different surfaces feel distinct. Standard haptic interfaces weren’t designed to output high-frequency vibrations, so we typically attach a voice-coil actuator (much like an audio speaker) to the handle, near the user’s fingertips. When the user is touching a virtual surface, we output data-driven tapping transients, friction forces, and texture vibrations to try to fool them into thinking they are touching the real surface from which the model was constructed.
After many years of research by my PhD students Heather Culbertson and Joe Romano, we’ve been able to create the most realistic haptic surfaces in the world. My work in haptography is motivated by a belief that there are myriad applications for highly realistic haptic virtual surfaces.
One exciting use is in recording what doctors and other clinical practitioners feel as they use various tools to care for their patients, such as inserting an epidural needle or examining teeth for decay (more on this below). Haptography would enable us to accurately simulate those interactions so that trainees can practice critical perceptualmotor skills on a computer model instead of on a human patient.
Another application that excites us is adding tactile feedback to online shopping. We’d love to use our technology to let consumers feel the fabrics and surfaces of products they’re considering without having to visit a physical store. Touch-mediated interaction plays an important role in many facets of human life; I hope that my team’s work on haptography will help bring highly realistic touch feedback into the digital domain.
Read Circuit Cellar’s interviews with other engineers, academics, and innovators.
CIRCUIT CELLAR: Which of the Penn Haptics Group’s projects most interest you at this time?
KATHERINE: That’s a hard question! I’m excited about all of the projects we are pursuing. There are a few I can’t talk about, because we’re planning to patent the underlying technology once we confirm that it works as well as we think it does. Two of those that are in the public domain have been fascinating me recently. Tactile Teleoperation: My lab shares a Willow Garage PR2 (Personal Robot 2) humanoid robot with several of the other faculty in Penn’s GRASP Lab. Our PR2’s name is Graspy.
While we’ve done lots of fun research to enable this robot to autonomously pick up and set down unknown objects, I’d always dreamed of having a great system for controlling Graspy from a distance. Instead of making the operator use a joystick or a keyboard, we wanted to let him or her control Graspy using natural hand motions and also feel what Graspy was feeling during interactions with objects.
My PhD student Rebecca Pierce recently led the development of a wearable device that accomplishes exactly this goal. It uses a direct drive geared DC motor with an optical encoder to actuate and sense a revolute joint that is aligned with the base joint of the operator’s index finger. Opening and closing your hand opens and closes the robot’s paralleljaw gripper, and the motor resists the motion of your hand if the robot grabs onto something. We supplement this kinesthetic haptic feedback with tactile feedback delivered to the pads of the user’s index finger and thumb. A voice coil actuator mounted in each location moves a platform into and out of contact with the finger to match what the robot’s tactile sensors detect. Each voice coil presses with a force proportional to what the corresponding robot finger is feeling, and the voice coils also transmit the high-frequency vibrations (typically caused by collisions) that are sensed by the MEMS-based accelerometer embedded in the robot’s hand. We track the movement of this wearable device using a Vicon optical motion tracking system, and Graspy follows the movements of the operator in real time. The operator sees a video of the interaction taking place. We’re in the process of having human participants test this teleoperation setup right now, and I’m really excited to learn how the haptic feedback affects the operator’s ability to control the robot.
CIRCUIT CELLAR: In your TEDYouth talk, you describe a project in which a dental tool is fitted with an accelerometer to record what a dentist feels and then replay it back for a dental student. Can you tell us a bit about the project?
KATHERINE: This project spun out of my haptography research, which I described above. While we were learning to record and model haptic data from interactions between tools and objects, we realized that the original recordings had value on their own, even before we distilled them into a virtual model of what the person was touching. One day I gave a lab tour to two faculty members from the Penn School of Dental Medicine who were interested in new technologies. I hit it off with Dr. Margrit Maggio, who had great experience in teaching general dentistry skills to dental students. She explained that some dental students really struggled to master some of the tactile judgments needed to practice dentistry, particularly in discerning whether or not a tooth surface is decayed (in popular parlance, whether it has a cavity). A few students and I went over to her lab to test whether our accelerometer-based technology could capture the subtle details of how decayed vs. healthy tooth tissue feels. While the recordings are a little creepy to feel, they are super accurate. We refined our approach and conducted several studies on the potential of this technology to be used in training dental students. The results were really encouraging, once again showing the potential that haptic technology holds for improving clinical training.
CIRCUIT CELLAR: What is the “next big thing” in the field of haptics? Is there a specific area or technology that you think will be a game changer?
KATHERINE: Of course this depends on where you’re looking. While cell phones and game controllers have had vibration alerts for a long time, I think we’re just starting to see highquality haptic feedback emerge in consumer products. Haptics can definitely improve the user experience, which will give haptic products a market advantage, but their cost and implementation complexity need to be low enough to keep the product competitive. On the research side, I’m seeing a big move toward tactile feedback and wearable devices. Luckily there are enough interesting open research questions to keep my students and me busy for 30 more years, if not longer!
The complete interview appears in Circuit Cellar 296 (March 2015).
Carmen Parisi is an applications engineer who co-hosts an engineering podcast in his spare time. In this interview, he describes his work, shares some engineering tips, and tells us about a fun prank he played on an unsuspecting designer.
CIRCUIT CELLAR: Where are you located?
CARMEN: Currently, I’m living and working in Raleigh-Durham, NC, around the Research Triangle Park area between the two cities with my wife and new dog Sadie. Kelly and I moved down about three years ago from Buffalo, NY, and really like it here. There’s a lot of tech companies and engineers around, tons of stuff to do, and great food and beer scenes. Plus, as a hearty Northerner, I get to laugh at the “cold” winters we experience. Come summer, though, I melt into a puddle on the pavement. Snow all the way for me, but Kelly disagrees.
CIRCUIT CELLAR: When did you decide to pursue electrical engineering and why?
CARMEN: Ever since I was a kid I had a fascination with tools and how things worked. I would always have a toy sword and various tools stuffed into my belt and would volunteer to help my dad around the house building a deck around the pool or fixing the fence.
Once I got into high school, I took a few basic engineering courses during which time I got bit by the engineering bug. The course that really “doomed” me to a life of electronics was a Robotics course taught by my favorite teacher C, as we called him. He put me through my paces learning how to solder, reading schematics, programming in BASIC, and robbing Fort Knox using a LEGO Mindstorms robot. C’s class solidified my choice to go to college for engineering, and shortly thereafter, I picked electrical over mechanical for my major.
CIRCUIT CELLAR: When was the first time you used a microcontroller in a project?
CARMEN: If we’re counting LEGO Mindstorms, then the Robotics class in tenth grade with C where we had to build a robot to lift a golden brick and run away with it (thus “robbing Fort Knox”). I met all the individual milestones with my group for the project, but we couldn’t get the whole thing working smoothly from beginning to end. I guess that was my first time learning how to successfully fail too which has turned out to be a very useful skill.
My first real microcontroller experience was the summer after sophomore year when I took a college course at a local community college offering a few classes to high school students interested in engineering. During that course I learned more basic circuit theory, got introduced briefly to SMT soldering, and built some robots using the Parallax BOE Bot. Looking back, I’d say this was the time my analog career kicked off as I slowly started to realize that I was more interested in the circuits themselves than the overall robot.
CIRCUIT CELLAR: Tell us about your university-level schooling.
CARMEN: I still consider myself a student in that I’m always looking to learn new things and grow as an engineer, but my formal schooling is over for the foreseeable future. In 2011, I completed a combined BS/MS degree in Electrical Engineering at the Rochester Institute of Technology in Rochester, NY. I initially started off interested in robotics but after working with a great analog designer on my first co-op at GE, I switched into the analog circuit and semiconductor track and never looked back.
CIRCUIT CELLAR: Can you tell us about your work in graduate school?
CARMEN: Sure thing. My graduate work was primarily with the Communications professor who needed a proof of concept built to test out a theory that looked plausible on paper. Prior to my joining the Comms Lab, my advisor and two past grad students had worked out a method of securing wireless channels using the randomness of the channel itself. There was an initial front end of sorts to test the idea out but I don’t think it was ever tested.
I looked over the circuit design, decided to scrap it and start fresh, and immediately realized I had a big job ahead of me. Cue the analog professor becoming my co-advisor. Mixing circuits, active filters, phase detectors, ADCs, and communication theory swam through my head as I slowly cajoled the circuit to life. Two PCB revisions later the circuit worked in that it took the RF input signal and spat out some bits at the other end, but after my advisor applied his algorithm to the data, we weren’t able to generate symmetric keys on different boards. Whether this was from an error in theory or with my board I never found out, as I ended the project there to focus on my full-time job leaving with a grad paper instead of a full thesis.
I still have all my old lab notebooks, schematics, and board layouts on my bookshelf at home. I think the files are sitting on a hard drive somewhere too. Looking at them now, I can spot a lot of little errors I’d like to fix due to my inexperience at the time and some maybe a few not so little errors too.
CIRCUIT CELLAR: What did you do after school?
CARMEN: After I left RIT, I moved down here to Raleigh-Durham to start my career as an Applications Engineer working on switching regulators with Intersil. Back in 2009 I had done a summer stint as an FAE at a small field office in Long Island with the company which got me interested in working in the semiconductor industry.
Life on the road as an FAE didn’t appeal to me after spending my college years constantly moving around for co-ops, so my former boss set me up with an interview here at the RTP design center. On the way down for the interview, I got stuck in Dulles for the night thanks to some bad weather in Rochester causing me to miss my connection. I wound up getting a bare 3 hours of sleep that night on an empty terminal bench. The next morning, groggy and sleep deprived, I suited up in the family restroom and flew out for six wonderful hours of technical interviews. I was absolutely wiped out by the end of the day but managed to survive the ordeal. The rest is history.
CIRCUIT CELLAR: Tell us about the work you are doing as an applications engineer for Intersil.
CARMEN: Well, for starters, being an apps engineer is exactly the rock n’ roll lifestyle I’m sure all your readers expect it to be. I roll into the office every morning and have the roadies warm up my iron for me!
In reality though, I work on buck regulators for computing applications like notebooks, tablets, ultrabooks, with maybe a bit of desktop work from time to time. Most of the parts I work on are for the primary core voltage on Intel processors. Sometimes, should the part integrate multiple regulators, I’ll work on a graphics rail or one of the other many voltage rails present on a motherboard. For each new processor tock (tick? I always confuse the two), Intel releases a laundry list of specs that have to be met in order to provide power to their CPUs and my parts are designed to those specs.
When I work apps on a brand spanking new chip, I’ll first work with the design engineers to run some feasibility studies and help define any new features for the IC. These tests range from tuning a similar part to the new Intel specs to see if the control scheme hits any corners or has stability issues to beating up some power FETs to determine if they can handle the new current requirements we have to meet. Once the chip tapes out, I’ll start work on preliminary documentation—a rough datasheet draft or early reference design based on feasibility testing and simulations—for the field to use when working with customers. During this time, I also design the evaluation board I’ll use to validate the part and send to customers for sampling.
The real meat and potatoes of my job is silicon validation. I’ve got an exhaustive spreadsheet of bench tests to do that functionally verify the IC over a wide range of corners. The first few weeks after silicon comes back I’m working full throttle, round the clock if need be, to make sure there are no show stopping bugs we need to address. I never see my office during validation. Instead I’m spending all my time in the lab hunched over the eval board or squinting at my scope.
Things calm down slightly after the initial validation, but the work is still nowhere near done. Now I’m working with design and test engineers to debug any issues that crept up during validation and implement fixes. Ideally, a board-level change is found because PCB or apps level schematic changes are much easier and cheaper than silicon spins. In conjunction with this work, I’ll also refine my reference designs and documentation as well as work with the field on initial customer designs by answering questions and checking over layouts and schematics to make sure everything’s optimal for their builds.
Up until the part releases, I’ll continue cycling through validation, debug, and customer support as needed, squeezing in documentation when I get a chance too. At any given time, I’m also supporting old parts still in production or, if I’m in a lull with my work, getting pulled onto other chips to help out other apps engineers in a jam.
The last part I released, and my first as the lead apps guy, was the ISL95813, a single phase regulator for Haswell and Broadwell systems. My next part is scheduled for release next year which I can’t talk too much about, but it’s really cool.
CIRCUIT CELLAR: During your time at Intersil, you must have learned some important lessons about professional engineering. Can you share one or two things you took from the experience?
CARMEN: Most importantly, good communication skills are key. A large chunk of my job is talking to other engineers and customers across the country and overseas. Their whole interaction with me is through the emails and reports I send out and I want to make sure they’re top notch. You don’t need to be a poet laureate by any means, but if you come across like a rock head, it will be much harder to get taken seriously and problems will drag out longer than necessary. Proofread your work; make sure you’re getting your point across clearly; and tailor your email, report, PowerPoint, whatever, to your audience’s level of technical expertise. Study up on how to make a slideshow that won’t bore your audience or read a technical writing guide. It can’t hurt.
Secondly, document, document, document—even if it’s only for your own reference. And keep it somewhat organized so you can find what you need again without too much hassle. Yes, it can help CYA, but also I’ve saved myself a ton of time not redoing the same derivations or looking back at a difficult test setup I had documented in my notebooks. It’s especially nice being able to pull up old data from past parts to see why the heck we did what we did years later.
CIRCUIT CELLAR: Tell us about your most recent electrical engineering project. What did you build and why?
CARMEN: Well, I can’t talk too much about work since all my projects at the moment are either customer related or under development, but suffice it to say I’m working on a lot of low power, multi-role chips.
Outside of work though for nearly two years now I’ve been co-hosting a podcast which keeps me plenty busy. The show’s called The Engineering Commons and it gets released every other week by myself and three other engineers scattered across the US. It was originally started by Chris Gammell and Jeff Shelton, but when Chris left the show for other projects back in 2013, I threw my hat into the ring when Jeff put the word out he was looking for new co-hosts. We discuss the engineering discipline as a whole rather than focus on any one field and some of our favorite topics include education, the value of co-ops, life in the workplace, and the stories of other engineers we bring on to interview.
The semiconductor field is pretty niche, and so through the show, I get exposed to all sorts of new ideas and philosophies, whether it’s from researching a topic when coming up with show notes or hearing the stories of engineers and professors from across the globe. Some of my favorite episodes are the ones while interviewing a guest I barely have to say anything and not just because I hate hearing my voice when I re-listen to an episode! Hearing someone get really into a story and talk about their passion I can’t help but get drawn in and become excited myself. All us engineers are alike; no matter the field once you get us going about that tricky bug we finally tracked down, the ridiculous meeting that happened the other day, or those ah-ha moments when a solution just clicks in your head we just can’t help but gush and it makes for great content. I’ve put out nearly 50 episodes with Jeff, Adam, and Brian, and I can’t wait to do the next 50!
CIRCUIT CELLAR: Tell our readers about the prank circuit gag you pulled on the designer you worked with. And can you share an image of the prank circuit?
CARMEN: A good way through the 813 development I found some problems that ended up being non-issues because I misinterpreted a spec, had a test setup issue, or made a silly component choice in my design. The designer started ribbing me a bit by immediately calling everything a board issue from that point on. This kind of back and forth goes on all the time between apps and design and it’s always good natured in tone. I didn’t take it personally and took strides to be more thorough before ringing alarm bells going forward but I couldn’t let him get way Scot-free.
With my boss’ permission I waited until a slow day came along and rigged up a little circuit to the bottom of the eval board that would overdrive the compensation node of our regulator, propagate through the control loop, and cause seemingly random spikes in the output voltage. I took some waveforms and sent them off to the designer explaining how I found an operational corner that affected regulation we needed to address. Since he was a thorough designer and liked to regularly pop into the apps lab I actually spent my morning running the tests he asked me to just to keep up the illusion something was wrong if he showed up.
I kept him digging through the schematics trying to find his mistake until mid-afternoon before I brought him in the lab and slowly flipped the board over while telling him I found the error was caused by a parasitic circuit. At this point a couple other engineers who were in on the gag had found reasons to be in the lab for the reveal and we all had a good laugh. The designer took it pretty well, and I even bought him a beer for being a good sport.
You can read the entire interview in Circuit Cellar 295 (February 2015).