Interview with Neil Gruending

Featured Engineer

Neil Gruending

Neil Gruending - Design Engineer, Gruending Design

How did you get into electronics/ engineering and when did you start?

Lots of electronics design engineers started playing with electronics when they were young. Unfortunately I’m not one of those people. I was always more of a tinkerer as a kid and I was always seemed to have a big pile of almost working inventions. In high school I was pretty good at math and physics so I figured robotics would be a good career choice. I ended up getting a Systems Engineering degree which was great for me because I learned about electronics, programming, sensors, actuators and mechanical design.

What are your favorite hardware tools that you use?

Like most engineers I mainly use multimeters and oscilloscopes for my work. My home lab has a Tek 754D and a 7704A oscilloscope. It also has more than 5 Agilent and Fluke multimeters all the way from a Agilent 34401A down to a Fluke 73. It sounds like a lot, but each instrument is specifically suited to different probing situations. I find that the real challenge is knowing when and how to use them.

What are your favorite software tools that you use?

When I design circuit boards I use Altium Designer at work or DesignSpark for stuff at home. When I write software I use some of the best open source software out there: GCC, Vim and Python. I really dislike Eclipse and avoid it when can.

What is the hardest/trickiest bug you have ever fixed?

There are two classes of bugs that I always find difficult to resolve: ones that only happen periodically and others that happen because you misunderstood the problem. I design a lot of automotive products so these types of problems happen regularly due to the hostile electrical and environmental characteristics of cars. Here’s a recent example of a periodic bug:

We had been shipping product for a while when we started to receive the occasional complaint that our product wasn’t booting. It would just sit there doing nothing until the watchdog timer kicked in or it was power cycled. That’s all the detail we could get from the customers since they were worried about there issues and not ours. Several visits to the customer sites didn’t add any new information.

I knew that it had to be a power problem but first I needed to figure out how to reproduce it. I tested several systems for weeks until I thought I had figured out the necessary steps. But the problem was random and I wanted to make sure I had narrowed down the cause because I wasn’t going to get a second chance to fix it. So before I could even fix the problem I had to accurately how often the problem occurred over a large sample size. I ended up using a programmable power supply and writing an automatic test suite that could control the power supply and measure all of the products in the sample to make sure they were operating properly. The test suite made it simple to generate test cases and measure the results until I can up with a worst case scenario. Now it was time to fix the problem.

I took apart the worst performing units and compared them to the best ones. After a lot of searching I narrowed it down to a power supply time constant that was easily changed with a new capacitor value. Testing the new change only took days instead of months because of the automated tests and we quickly put the changes into production. Shortly afterwards our customers stopped complaining about the issue.

What is on your bookshelf?

I have a quite a few books, but I’ll just list the ones that really influenced me. “High-Speed Digital Design” by Dr Howard Johnson really changed the way I design circuit boards and I really like the practical nature of the book that makes its topics easier to remember. “Troubleshooting Analog Circuits” by Bob Pease is a great read on how to use all that test gear sitting on the bench. I also like Jim Williams books “Analog Circuit Design” and “The Art and Science of Analog Circuit Design”. There’s a tremendous of industry knowledge in those books. My most recent addition is the “Art of Electronics” by Paul Horowitz and Winfield Hill.

Do you have any tricks up your sleeve?

Electronics is as much art as it is science. My simple rule is to think before you act, especially when you’re just starting out. It starts at the design stage where I do my best to make my designs testable and I try and visualize how the circuit will work before committing to a circuit board. When I layout a board I try and consider all the issues that can occur. This thought process saves me a bunch of time because I catch most of my errors pretty early in the design.

What has been your favorite project?

I’ve been fortunate to work on many interesting projects. One of my favorite projects that I’ve worked on recently was a high current DC-DC convertor. It needed 25A of input current to run which make the design interesting since the layout took a lot of planning to work properly.

What future projects do you have planned?

I have an unhealthy obsession with Christmas lights and I would like to design an open source LED lighting solution. I think it would be fun to try the open source hardware model and see how well it works. The scope of the project would also be interesting because I intend to control several thousand individual RGB LEDs in real time.

What are some of the challenges you’ve faced in your career?

Where I live I’m a hardware guy in a software world. I have to constantly work on networking with other people in the electronics industry in order to stay relevant since the market here is too small for most distributors to care about. I also have to constantly update my skills on my own since training classes and seminars aren’t available. But I think that extra work is worth it and that it helps me be a better engineer.