Q&A: Chris Paiano (Problem Solving & Design)

Chris Paiano is an Elko, NV-based problem engineer. His father introduced him to programming at an early age, and Chris has continued to team with his father to write software and firmware for some of his hardware designs. Chris has written dozens of unique application notes for the Cypress Semiconductor Programmable-System-on-Chip (PSoC) chipset. He is currently using PSoC in an innovative household project and dreams of finishing his concept for environmentally friendly electric/hybrid vehicle wheeldrive retrofit kits.

Chris Paiano working with his “office assistants” (bearded dragons)

You can read the complete interview in Circuit Cellar 272 March 2013.

NAN PRICE: Tell us a little about your background.

CHRIS PAIANO: I went to school in Orlando, FL, all the way through college at the University of Central Florida, where I obtained my bachelor’s degree in Computer Engineering.

I started at a very young age. My father always had an electronics workbench and I spent time there when I could. When I was 2 years old, he brought me home an Apple ][ with some floppy disks and told me there were games to be played—if I could only figure out how to make them work.

The Apple ][ was not the most user-friendly or intuitive computer system, by any means. In order to accomplish my important goal of playing video games, I had to learn how to work with the computer’s clunky command-line interface (CLI). Once I figured out how to make all the games work, I wanted to fully automate them so I didn’t have to go through all the manual steps to play them every time (also, so my friends could start them up without me). So, I spent much time developing automatic start-up scripts, from the Applesoft HELLO program to MS-DOS configuration start-up menus, supporting whatever memory management method was required to play certain games, along with icon-driven pre-Windows menu systems that made these early systems usable by my friends, family, and clients.

This evolved into more elaborate scripting and programming to fill the gaps where the tools I needed did not exist, so I had to create them. My possibilities really opened up when I began developing firmware to complement my father’s hardware designs.

NAN: Tell us about your company, Christopher Paiano Engineering (CpE).

CHRIS: I design and program prototypes for various clients. I provide them with ideas at various development stages, which I turn into something that they can mass produce. I’ve just redesigned my website (www.cpeproto.com), by the way. It has a sleeker, simple interface and is easier to navigate now. No more Java menu with annoying sound effects!

NAN: Several of your projects are built around the Cypress Semiconductor programmable system-on-chip (PSoC). Is that your go-to chipset?

CHRIS: Yes, mainly because of how versatile and capable it is. It seems to be sufficient to take care of most any embedded task or set of tasks that come to mind.

For example, recently, the proprietor of a local game/tech/arcade business approached me to build a custom, inexpensive door chime. He wanted customers to hear random, recognizable portal sounds from popular video games whenever customers entered or exited his shop.

I started with an inexpensive motion sensor product from a local superstore. I added a Cypress CY8C27443 PSoC, as I have several lying around for general projects. I made a copy of my “Playing WAV Files with a PSoC” app note project to modify.

I added code to randomly cycle through available sound clips in the memory and I was able to provide 1.9805 s of audio at 8 kHz with the 16 KB of RAM available in this chip. The client was happy with this. He settled on two portal sounds (from The Legend of Zelda and Super Mario Brothers) and the chime has been in use for several months now. Customer feedback has been excellent. Everyone entering the place immediately recognizes the sounds and loves it!

NAN: You’ve written more than 30 application notes for the Cypress chipset, including PongSoC and the Video RTA. Can you explain the process?

CHRIS: Sometimes Cypress would post bounties for app notes that they’d like to see written on a certain topic or capability. Other times, I’d have an interesting personal project for which I decided to utilize a PSoC. I would then decide it might make a good app note, so I’d write it up and submit it. Either way, I’d usually develop the project side-by-side with my father. (We make an excellent hardware/software team.) I work out whatever firmware and PC/smartphone apps may be necessary, and he builds the PSoC circuit board with which to test. Then, I document it all, arrange it, and edit it into an app note (or, in some cases, an article).

Sometimes a project is just too complex to squeeze into a single PSoC’s resources and the simplest solution is to just add another PSoC. Communication between PSoCs can be quick and easy to implement, so distributing tasks and maintaining synchronization is not too difficult. This was the solution for the video real-time analyzer (RTA) app note where, realistically, there were only enough internal analog resources to provide three filters in each PSoC. With the Video RTA, one just adds as many PSoCs to the bus as is necessary to achieve the desired analyzer resolution.

The PongSoC was a fun one! Once I learned it was possible to combine some internal PSoC modules and algorithms to generate a stable composite video signal, I immediately decided I wanted to try and utilize this new capability to recreate a Pong-like embedded game-on-a-chip. I could already generate sound effects and read potentiometers for paddle inputs, I just needed to work it all out. I had a great time doing so, testing it with friends and playing with the variables to tweak the gameplay, and so forth.

Additionally, all 40 of my PSoC application notes are now available in some capacity on my updated website, as Cypress does not actively market the older PSoC families that many of my projects utilized in the past. I get enough e-mail requests for source code and documentation from this collection, so I have just gone ahead and taken the time to restore as many as I could find from my archives to the new website.

NAN: Your two-part article series “PSoC Design Techniques” describes how to build an eight-channel mixer and how DSP effects and a user interface can be added to it (Circuit Cellar 216–217, 2008). Describe the design and why you chose this design concept.

CHRIS: This was a great challenge. In a chip that traditionally would only allow for four full audio pathways in the provided analog resources (four PGA modules utilizing the normal I/O paths provided by PSoC Designer), we managed to figure out a way to utilize the remaining switched-capacitor blocks to act as signal mixers and gain stages with enough live reconfigurable resources to add potentiometers to control volume for each channel. Since there was still plenty of code space, I went ahead and added some DSP effects (reverb and pitch shift) along with a voice menu and flash-settings memory.

I really wanted to showcase what efficient design and algorithms could accomplish in a single piece of silicon, and I’m quite pleased with the way this project turned out. I still use the resulting device on my workbench and in my setups. It comes in handy sometimes. I have not updated it at all. I’ve been using it as is and it is still available for purchase on my website for anyone interested in experimenting with one.

NAN: Are you currently working on or planning any microprocessor-based projects?

CHRIS: Currently, I’m working on a PSoC solution for my broken dishwasher.

Chris Paiano is developing a PSoC solution for a broken dishwasher. In addition to the fix, he plans to make it smartphone-controllable.

The control module on this appliance has failed, so I am wiring it into a PSoC to make it work again as well as add some new capabilities (such as keeping a wash/rinse/door open log so it can tell when the dishes contained within it are clean or dirty, and adding a Bluetooth module so I can check the status and control/program the appliance from my smartphone).

This is the type of personal project I like to work on in my free time. It also might make a good app note or article in the future, as it involves an Android application and Bluetooth communication. It also increases my capabilities, if I have to figure out anything new. And that is always good.

I am almost ready to hook it up to the dishwasher, let it try running through the cycles, and hope I don’t flood my house in the process. Ah, the pure excitement of engineering!

The entire interview is available in Circuit Cellar 272 March 2013.

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.