Q&A: Miguel Sanchez (Professor, Designer)

Miguel Sánchez (PhD, Computer Science) is Valencia, Spain-based computer scientist, embedded tech enthusiast, and professor who regularly challenges himself to design innovative microcontroller-based systems. Since 2005, Circuit Cellar has published six of his articles about projects such as a digital video recorder (Circuit Cellar 174) and a creative DIY image-processing system (Circuit Cellar 263).

This is a sample depth image projected in a 3-D space. It appeared in Sanchez’s article, “Image Processing System Development.” (Source: M. Sanchez, Circuit Cellar 263)

In the September issue of Circuit Cellar, Sánchez tells us about his background, his work at the Universitat Politècnica de València, his current interests, and his innovative designs. An abridged version of the interview follows.

NAN PRICE: How long have you been designing microcontroller-based systems?

MIGUEL SANCHEZ: I started using computers in 1978. I built my first microcontroller project in 1984 during my first year at Universitat Politècnica de València. I haven’t stopped designing embedded systems since then.

NAN: Tell us about the first microcontroller you worked with. Where were you at the time?

MIGUEL: Our university’s lab had Intel SDK-85 boards you could program in Hex using the built-in keyboard. I guess it wasn’t built well. You sometimes lost all your work while typing your code. I learned that schematics were available and a terminal monitor was built in too. So, I built my first microcontroller-based board around an Intel 8085 using the same software that was on the original ROM. But, I changed the serial port delay value so I could use 9,600 bps instead of the original 110 bps on the terminal port. This way, I could do the same labs as my mates, but I could do my work in 8080 Assembler, which was available in Control Program/Monitor (CP/M) computers. At the time, I had an Atari 1040 ST that could run CP/M on top of a Z-80 emulator. Assembly code could be uploaded to my board’s RAM memory and later executed using SDK-85 serial monitor code.

I used the 8085’s Wait signal to build an additional EEPROM socket in this same board that, with the aid of a 555 timer, was my first EEPROM programmer. I used the Wait signal to delay write operations. In fact, I used this programmer to change the original baud rate to the new one, as I originally did not know that was something I’d want to change later.

My teacher, who is now one of my colleagues, was quite amused with my development and he gave me an A+. I learned a lot about microcontrollers, serial communications, Assembly language, monitor programs, and EEPROM programming algorithms. And, I learned it was not fun to design PCBs with system buses on only one copper layer. …

NAN: You designed a system to simulate strokes on a keypad to trigger modes on an alarm system (“Reverse-Engineered ECP Bus,” Circuit Cellar 201, 2007). Why did you design it and how have you used it?

MIGUEL: A local company wanted to give new life to old Ademco alarm units. These boards could only be programmed by a serial port socket once a certain service code was typed at the keyboard. I was asked whether an add-on board could be created to make these old boards Internet-enabled so they could be remotely managed and reconfigured over the ’Net.

The first thing I needed to do was to figure out how to simulate the required keystrokes. But I couldn’t find any information about the way that bus worked, so I figured that out myself. Later, I thought both the information itself and the way I figured it out might be useful to others, so I approached Circuit Cellar editors with a proposal to write an article.

That project ended up as a Rabbit-core powered board that connected the alarm board and the remote access to its serial port. Combined with a virtual serial port on the PC, it fooled the original management software into thinking the PC was directly connected to the alarm board, although it was all happening over the Internet. But the project never made it to the market for reasons unknown.

NAN: In “Three-Axis Stepper Controller” (Circuit Cellar 234, 2010), you describe how you built an Arduino-based, platform-independent driver board. Tell us about the design.

MIGUEL: When I discovered the Arduino platform, I was surprised by a few things. First, this development system was not designed by a chip vendor. Second, it was not intended for engineers but for artists! Third, I was shocked because it was multiplatform (which was possible because it was based on Java and GCC) and because none of the other development systems I was aware of were so easy to use. The price was low too, which was a plus for hobbyists and students.

The aim of that project was to show all that to the readers. The idea was also not only to show how to build a stepper controller and to explain the difference between the drive modes and the bipolar and unipolar designs, but to demonstrate how easy it was to work with Arduino.

In his 2010 article, “Three-Axis Stepper Controller,” Sanchez provided this controller circuit schematic to interface Arduino I/O headers with stepper motors. (Source: M. Sanchez, Circuit Cellar 234)

NAN: Your most recent Circuit Cellar article, “Image Processing System Development: Use an MCU to Unleash the Power of Depth Cameras” (263, 2012), describes how you used Microsoft’s Kinect motion-sensing device for an interactive art project. Tell us about the project and how you came to be involved.

MIGUEL: My university offers a master’s degree in fine arts. I met a professor from the drawing department who had seen a video of my vertical plotter on YouTube and was interested in contacting me, as we worked on the same campus. We became friends and he asked me to help him out with an idea for an installation.

The first approach used an RGB camera, but then Kinect was launched. From what I read on the ’Net, I was convinced it would be a better mousetrap. So, I bought one unit and started learning how to use it, thanks to the hack that had been made available.

The project required gathering visitors’ silhouettes and later drawing them on a big wall. The drawing was performed with a properly scaled-up version of my vertical plotter, which, by the way, was controlled by an Arduino board.

I have found working with artists is a lot of fun too, as they usually have a totally different vision than engineers.

The full article appears in the September issue.

Q&A: Guido Ottaviani (Roboticist, Author)

Guido Ottaviani designs and creates innovative microcontroller-based robot systems in the city from which remarkable innovations in science and art have originated for centuries.

Guido Ottaviani

By day, the Rome-based designer is a technical manager for a large Italian editorial group. In his spare time he designs robots and interacts with various other “electronics addicts.” In an a candid interview published in Circuit Cellar 265 (August 2012), Guido described his fascination with robotics, his preferred microcontrollers, and some of his favorite design projects. Below is an abridged version of the interview.

NAN PRICE: What was the first MCU you worked with? Where were you at the time? Tell us about the project and what you learned.

GUIDO OTTAVIANI: The very first one was not technically an MCU, that was too early. It was in the mid 1980s. I worked on an 8085 CPU-based board with a lot of peripherals, clocked at 470 kHz (less than half a megahertz!) used for a radio set control panel. I was an analog circuits designer in a big electronics company, and I had started studying digital electronics on my own on a Bugbook series of self-instruction books, which were very expensive at that time. When the company needed an assembly programmer to work on this board, I said, “Don’t worry, I know the 8085 CPU very well.” Of course this was not true, but they never complained, because that job was done well and within the scheduled time.

I learned a lot about how to optimize CPU cycles on a slow processor. The program had very little time to switch off the receiver to avoid destroying it before the powerful transmitter started.

Flow charts on paper, a Motorola developing system with the program saved on an 8” floppy disk, a very primitive character-based editor, the program burned on an external EPROM and erased with a UV lamp. That was the environment! When, 20 years later, I started again with embedded programming for my hobby, using Microchip Technology’s MPLAB IDE (maybe still version 6.xx) and a Microchip Technology PIC16F84, it looked like paradise to me, even if I had to relearn almost everything.

But, what I’ve learned about code optimization—both for speed and size—is still useful even when I program the many resources on the dsPIC33F series…

NAN: You worked in the field of analog and digital development for several years. Tell us a bit about your background and experiences.

GUIDO: Let me talk about my first day of work, exactly 31 years ago.

Being a radio amateur and electronics fan, I went often to the surplus stores to find some useful components and devices, or just to touch the wonderful receivers or instruments: Bird wattmeters, Collins or Racal receivers, BC 312, BC 603 or BC 1000 military receivers and everything else on the shelves.

The first day of work in the laboratory they told to me, “Start learning that instrument.” It was a Hewlett-Packard spectrum analyzer (maybe an HP85-something) that cost more than 10 times my annual gross salary at that time. I still remember the excitement of being able to touch it, for that day and the following days. Working in a company full of these kinds of instruments (the building even had a repair and calibration laboratory with HP employees), with more than a thousand engineers who knew everything from DC to microwaves to learn from, was like living in Eden. The salary was a secondary issue (at that time).

I worked on audio and RF circuits in the HF to UHF bands: active antennas, radiogoniometers, first tests on frequency hopping and spread spectrum, and a first sample of a Motorola 68000-based GPS as big as a microwave oven.

Each instrument had an HPIB (or GPIB or IEEE488) interface to the computer. So I started approaching this new (for me) world of programming an HP9845 computer (with a cost equivalent to 5 years of my salary then) to build up automatic test sets for the circuits I developed. I was very satisfied when I was able to obtain a 10-Hz frequency hopping by a Takeda-Riken frequency synthesizer. It was not easy with such a slow computer, BASIC language, and a bus with long latencies. I had to buffer each string of commands in an array and use some special pre-caching features of the HPIB interface I found in the manual.

Every circuit, even if it was analog, was interfaced with digital ports. The boards were full of SN74xx (or SN54xx) ICs, just to make some simple functions as switching, multiplexing, or similar. Here again, my lack of knowledge was filled with the “long history experience” on Bugbook series.

Well, audio, RF, programming, communications, interfacing, digital circuits. What was I still missing to have a good background for the next-coming hobby of robotics? Ah! Embedded programming. But I’ve already mentioned this experience.

After all these design jobs, because my knowledge started spreading on many different projects, it was natural to start working as a system engineer, taking care of all the aspects of a complex system, including project management.

NAN: You have a long-time interest in robotics and autonomous robot design. When did you first become interested in robots and why?

GUIDO: I’ve loved the very simple robots in the toy store windows since I was young, the same I have on my website (Pino and Nino). But they were too simple. Just making something a little bit more sophisticated required too much electronics at that time.

After a big gap in my electronics activity, I discovered a newly published robotic magazine, with an electronic parts supplement. This enabled me to build a programmable robot based on a Microchip PIC16F84. A new adventure started. I felt much younger. Suddenly, all the electronics-specialized neurons inside my brain, after being asleep for many years, woke up and started running again. Thanks to the Internet (not yet available when I left professional electronics design), I discovered a lot of new things: MCUs, free IDEs running even on a simple computer, free compilers, very cheap programming devices, and lots of documentation freely available. I threw away the last Texas Instruments databook I still had on my bookshelf and started studying again. There were a lot of new things to know, but, with a good background, it was a pleasant (if frantic) study. I’ve also bought some books, but they became old before I finished reading them.

Within a few months, jumping among all the hardware and software versions Microchip released at an astonishing rate, I found Johann Borenstein et al’s book Where Am I?: Systems and Methods for Mobile Robot Positioning (University of Michigan, 1996). This report and Borenstein’s website taught me a lot about autonomous navigation techniques. David P. Anderson’s “My Robots” webpage (www.geology.smu.edu/~dpa-www/myrobots.html) inspired all my robots, completed or forthcoming.

I’ve never wanted to make a remote-controlled car, so my robots must navigate autonomously in an unknown environment, reacting to the external stimuli. …

NAN: Robotics is a focal theme in many of the articles you have contributed to Circuit Cellar. One of your article series, “Robot Navigation and Control” (224–225, 2009), was about a navigation control subsystem you built for an autonomous differential steering explorer robot. The first part focused on the robotic platform that drives motors and controls an H-bridge. You then described the software development phase of the project. Is the project still in use? Have you made any updates to it?

The “dsNavCon” system features a Microchip Technology dsPIC30F4012 motor controller and a general-purpose dsPIC30F3013. (Source: G. Ottaviani, CC224)

GUIDO: After I wrote that article series, that project evolved until the beginning of this year. There is a new switched power supply, a new audio sensor, the latest version of dsNav dsPIC33-based board became commercially available online, some mechanical changing, improvements on telemetry console, a lot of modifications in the firmware, and the UMBmark calibration performed successfully.

The goal is reached. That robot was a lab to experiment sensors, solutions, and technologies. Now I’m ready for a further step: outdoors.

NAN: You wrote another robotics-related article in 2010 titled, “A Sensor System for Robotics Applications” (Circuit Cellar 236). Here you describe adding senses—sight, hearing, and touch—to a robotics design. Tell us about the design, which is built around an Arduino Diecimila board. How does the board factor into the design?

An Arduino-based robot platform (Source: G. Ottavini, CC236)

GUIDO: That was the first time I used an Arduino. I’ve always used PICs, and I wanted to test this well-known board. In that case, I needed to interface many I2C, analog sensors, and an I2C I/O expander. I didn’t want to waste time configuring peripherals. All the sensors had 5-V I/O. The computing time constraints were not so strict. Arduino fits perfectly into all of these prerequisites. The learning curve was very fast. There was already a library of every device I’ve used. There was no need for a voltage level translation between 3.3 and 5 V. Everything was easy, fast, and cheap. Why not use it for these kinds of projects?

NAN: You designed an audio sensor for a Rino robotic platform (“Sound Tone Detection with a PSoC Part 1 and Part 2,” Circuit Cellar 256–257, 2011). Why did you design the system? Did you design it for use at work or home? Give us some examples of how you’ve used the sensor.

GUIDO: I already had a sound board based on classic op-amp ICs. I discovered the PSoC devices in a robotic meeting. At that moment, there was a special offer for the PSoC1 programmer and, incidentally, it was close to my birthday. What a perfect gift from my relatives!

This was another excuse to study a completely different programmable device and add something new to my background. The learning curve was not as easy as the Arduino one. It is really different because… it does a very different job. The new PSoC-based audio board was smaller, simpler, and with many more features than the previous one. The original project was designed to detect a fixed 4-kHz tone, but now it is easy to change the central frequency, the band, and the behavior of the board. This confirms once more, if needed, that nowadays, this kind of professional design is also available to hobbyists. …

NAN: What do you consider to be the “next big thing” in the embedded design industry? Is there a particular technology that you’ve used or seen that will change the way engineers design in the coming months and years?

GUIDO: As often happens, the “big thing” is one of the smallest ones. Many manufacturers are working on micro-nano-pico watt devices. I’ve done a little but not very extreme experimenting with my Pendulum project. Using the sleeping features of a simple PIC10F22P with some care, I’ve maintained the pendulum’s oscillation bob for a year with a couple of AAA batteries and it is still oscillating behind me right now.

Because of this kind of MCU, we can start seriously thinking about energy harvesting. We can get energy from light, heat, any kind of RF, movement or whatever, to have a self-powered, autonomous device. Thanks to smartphones, PDAs, tablets, and other portable devices, the MEMS sensors have become smaller and less expensive.

In my opinion, all this technology—together with supercapacitors, solid-state batteries or similar—will spread many small devices everywhere to monitor everything.

The entire interview is published in Circuit Cellar 265 (August 2012).

Q&A: Ayse Kivilcim Coskun (Engineer, BU)

Ayse Kivilcim Coskun’s research on 3-D stacked systems has gained notoriety in academia, and it could change the way electrical engineers and chip manufacturers think about energy efficiency for years to come. In a recent interview, the Boston University engineering professor briefed us on her work and explained how she came to focus on the topics of green computing and 3-D systems.

Boston University professor Ayse Kivilcim Coskun

The following is an excerpt from an interview that appears in Circuit Cellar 264 (July 2012), which is currently on newsstands.

NAN: When did you first become interested in computer engineering?

AYSE: I’ve been interested in electronics since high school and in science and physics since I was little. My undergraduate major was microelectronics engineering. I actually did not start studying computer engineering officially until graduate school at University of California, San Diego. However, during my undergraduate education, I started taking programming, operating systems, logic design, and computer architecture classes, which spiked my interest in the area.

NAN: Tell us about your teaching position at the Electrical and Computer Engineering Department at Boston University (BU).

AYSE: I have been an assistant professor at BU for almost three years. I teach Introduction to Software Engineering to undergraduates and Introduction to Embedded systems to graduate students. I enjoy that both courses develop computational thinking as well as hands-on implementation skills. It’s great to see the students learning to build systems and have fun while learning.

NAN: As an engineering professor, you have some insight into what excites future engineers. What “hot topics” currently interest your students?

AYSE: Programming and software design in general are certainly attracting a lot of interest. Our introductory software engineering class is attracting a growing number of students across the College of Engineering every year. DSP, image processing, and security are also hot topics among the students. Our engineering students are very keen on seeing a working system at the end of their class projects. Some project examples from my embedded systems class include embedded low-power gaming consoles, autonomous toy vehicles, and embedded systems focusing on healthcare or security applications …

NAN: How did you come to focus on energy efficiency and thermal challenges?

AYSE: Energy efficiency has been a hot topic for embedded systems for several decades, mainly due to battery-life restrictions. With the growth of computing sources at all levels—from embedded to large-scale computers, and following the move to data centers and the cloud—now energy efficiency is a major bottleneck for any computing system. The focus on energy efficiency and temperature management among the academic community was increasing when I started my PhD. I got especially interested in thermally induced problems as I also had some background on fault tolerance and reliability topics. I thought it would be interesting to leverage job scheduling to improve thermal behavior and my advisor liked the idea too. Temperature-aware job scheduling in multiprocessor systems was the first energy-efficiency related project I worked on.

NAN: In May 2011, you were awarded the A. Richard Newton Graduate Scholarship at the Design Automation Conference (DAC) for a joint project, “3-D Systems for Low-Power High-Performance Computing.” Tell us about the project and how you became involved.

AYSE: My vision is that 3-D stacked systems—where multiple dies are stacked together into a single chip—can provide significant benefits in energy efficiency. However, there are design, modeling, and management challenges that need to be addressed in order to simultaneously achieve energy efficiency and reliability. For example, stacking enables putting DRAM and processor cores together on a single 3-D chip. This means we can cut down the memory access latency, which is the main performance bottleneck for a lot of applications today. This gain in performance could be leveraged to run processors at a lower speed or use simpler cores, which would enable low-power, high-performance computing. Or we can use the reduction in memory latency to boost performance of single-chip multicore systems. Higher performance, however, means higher power and temperature. Thermal challenges are already pressing concerns for 3-D design, as cooling these systems is difficult. The project focuses on simultaneously analyzing performance, power, and temperature and using this analysis to design system management methods that maximize performance under power or thermal constraints.

I started researching 3-D systems during a summer internship at  the Swiss Federal Institute of Technology (EPFL) in the last year of my PhD. Now, the area is maturing and there are even some 3-D prototype systems being designed. I think it is an exciting time for 3-D research as we’ll start seeing a larger pool of commercial 3-D stacked chips in a few years. The A. Richard Newton scholarship enabled us to do the preliminary research and collect results. Following the scholarship, I also received a National Science Foundation (NSF) CAREER award for designing innovative strategies for modeling and management of 3-D stacked systems.

The entire interview appears in Circuit Cellar 264  (July 2012).

Q&A: Aubrey Kagan (Engineer, Author)

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

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

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

NAN PRICE: What is your current occupation?

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

Engineer and author Aubrey Kagan

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

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

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

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

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

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

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

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

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

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

Circuit Cellar 263 (June 2012) is now available.

EE’s Two-Bench Workspace in Silicon Valley

I met Vincent Himpe—a Senior Staff Engineer at STMicroelectronics—a few years ago at the Emebdded Systems Conference in San Jose, CA. It took all of about 5 minutes to learn that he was an engineer with a lot on his mind. Himpe described his work on hard disk drives, sketched a few circuits on a piece of paper, and even mentioned a few ideas for books. (Yes, that’s books—plural.) Where does such a productive engineer get so many ideas and all that energy? I wondered after we parted. I didn’t get to ask him before the conference ended.

Fortunately, Himpe recently contacted me, so I took the opportunity to get more insight into the life of such a multitalented engineer. I sent him a few questions via email, and he kindly replied. We have some insight into where he does a lot of creating, problem solving, programming, and writing.

When Himpe isn’t working on advanced controller devices for hard disk drives at STMicro, he’s writing books (check out Mastering the I2C Bus, Elektor 2011), tackling personal design projects, and repairing surplus electronic electronic equipment in two-bench workspace in San Jose.

My short interview with Himpe appears after the following two photos of his San Jose-based workspace.

Vincent Himpe’s workbench for hardware development

Himpe’s workbench for programming

C. J.: What are you working these days?

VINCENT: I make the reference designs and the development system for a hard disk mechatronic interface chip. This chip spins the 3 phase motor, does the head positioning including velocity control for the seek algorithms, shock sensing (to park the heads when freefall or shock is detected), provides power to all other parts (it’s got 4 switching regulators onboard). In case of unexpected power loss, we protect the data by retracting the heads. We recycle the mechanical energy in the spinning platters by using the motor as generator. This gives us a few seconds of power where we can gracefully shutdown the drive, preventing disasters.

C. J.: What sorts of projects do you work on at these two workstations? Work-related projects? Personal projects?

VINCENT: Personal projects. I have a number of books published through Elektor. Some of the hardware for those was developed there.

C. J.: Can you tell us a bit about the equipment at your hardware workstation? What do you use most frequently?

VINCENT: This is almost all salvaged equipment that was half functioning or broken. Some machines were repaired by combining two broken ones. I scout local surplus stores and eBay for damaged equipment. And once in a while you get lucky. There was a local company moving to a new building. They had ceased hardware development a couple of years ago and only do IP blocks now. They had a “yard sale.” That’s where I picked up my logic analyzer and my favorite scope: an Agilent mso7104: 4 analog and 16 digital channels 1GHz bandwidth with deep memory and all the protocols enabled.

C. J.: It looks like you’re working on something at the hardware bench. On the shelf is some equipment with red wires.

VINCENT: Those are three bench power supplies e3410 from Agilent. Next to it are three 34401 multimeters, also Agilent. I’m a bit of an Agilent fan. The fact that you can easily get full-service manuals that include schematics, calibration and troubleshooting procedures makes it ideal to fix these machines. That’s not the case with many other brands. Plus, they are built to last.

C. J.: What’s the piece of equipment directly under the magnifier/lamp?

VINCENT: Looks like a roll of desoldering wick. I was working on the ringlight. You can see a circular PCB just above it. Thirty-six white LEDs driven by a current-controlled boost pump with PWM. The halogen light bulbs in my Mantis burn out too easily. So I will replace them with this ringlight.

C. J.: How many solder stations do you have at your hardware station?

VINCENT: About seven. I have a Microtouch for precision work, SMD tweezers to remove passives, a hot air pencil, two WSP80s with different tips (so I don’t have to switch tip continuously while working), and a regular desoldering station with a vacuum pump. These are all surplus and/or repaired machines.

C. J.: What is board you’re working with at your software station?

VINCENT: That is a controller board for a UV exposure unit to make PCBs. It’s got an ATmega328 and LCD display. The board does double duty as pizza oven reflow controller. Just install two thermocouple interface chips and change software.

CircuitCellar.com is an Elektor International Media (EIM) publication. EIM published Himpe’s book, Mastering the I2C Bus.