Bench Talk

If you work in or follow the defense industry, you may have sensed a trend toward multifunctionality in U.S. Department of Defense (DoD) thinking – that everything it deploys in the future should perform multiple functions. It’s a logical concept when money is scarce, but it rarely works, especially if the functions to be combined are very different from each other. Smartphones, which today do everything but keep you healthy (that’s coming in iOS8), are a rare exception.

I am going to share a trade secret with you today. Did you know you could read an analog signal even if you only have digital inputs on your microcontroller or single board computer? It used to be a common practice, but maybe not so much anymore, judging by the questions I have been asked recently. But you can, and all you need is a simple resistor and capacitor.

Neil Armstrong’s favorite quote was "Science is about what is, engineering is about what can be.” STEM, and now STEAM (Science, Technology, Engineering, Art, and Mathematics) promote these areas for growth. Some might consider the “Art” in STEAM to be out of place, but I disagree. Engineers need cross-pollination, and have you seen some of the incredible art using open source technology?

According to some published studies, the area has the 10th worst traffic in the U.S. and the longest average commute in the US. I have given extensive thought to the social ramifications of self-driving cars. I have thought about this many times before, but now it is personal. The technology used in self-driving cars is fascinating, but I want to talk about the implications.

Let’s face it - circuit protection can be a tough sell. Here’s why: 1) Circuit protection isn’t sexy. It doesn’t add any “wow factor to the product." 2) In fact, it doesn’t add any functionality to the product at all. 3) Any effect circuit protection has on the function of a device is likely negative. Adding capacitance, resistance or potential non-linearity to an I/O port is rarely useful in promoting high data rates. 4) It adds cost and can increase complexity. What circuit protection does do is provide some measure of reliability. It gives the end product the ability to sustain and likely survive potentially damaging electrical surges or contact with unexpectedly high voltages without exposing the user to electrical shock or becoming a fire hazard.

If you use RF power transistors, you may have come across a new term of late on the datasheets: video bandwidth (VBW). Now, anyone who uses spectrum analyzers knows about this key metric, but I’ve been poring over power transistor datasheets for years, and this one seemed to appear out of nowhere.

My family is mildly crazy and the stunt for this past Spring was driving from Los Angeles to Indianapolis in 72 hours. One of my brothers was graduating in Los Angeles and another was getting married near Indianapolis. About 90 minutes out of LA, our car overheated. Naturally my mom and I decided to open the hood and see what we could do. As I poured water over the radiator, I noticed that in some spots the water was boiling on contact and other places it was rolling off and dripping onto the ground. I thought about my thermal class. In particular I was thinking of thermal contact resistance. I recalled a particularly illustrative picture from Chapter 10 of my thermal book and the heat conduction of road dust versus metal (Hint: it is not helping with the heat transfer).

Android, iOS tablets, and smartphones revolutionized the idea of the User Interface (UI). These devices are intuitive, powerful, and omnipresent in our daily lives. So instead of reinventing the wheel for a slick UI to control your next OSHW project, why not simply build the interface as an app? Typically the answer is that creating apps isn't quite as simple as using apps.

Now here’s a scary thought: You’re driving down the freeway in heavy traffic when the LCD screen in your dashboard that was previously displaying a song title suddenly informs you that the firmware for your car’s 100+ electronic control units (ECUs) has been updated wirelessly and you need to reboot your car for them to take effect. What happens if you’re distracted and don’t press the No button soon enough? If your car were my PC it would reboot automatically. Not so good at 70 mph.

My telecoms class had an end of the year project. You know it is interesting how you do not really think about all you have learned and how fascinating and wonderful it is until the end of the semester. This telecoms project is a great example of making students think about what we learned. It involved suppressing photos and video. We had talked about bandwidth suppression all semester. It made sense. A smaller channel transmitting the same amount of information is always desirable. It was interesting to learn that since our ears, unlike our eyes, are insensitive to phase distortion it is possible to design cheaper filters that allow phase distortion to slip through.