Featured Engineer

Interview with Jeff Crystal and Phillip Stearns

Jeff Crystal and Phillip Stearns

Jeff Crystal - COO and Phillip Stearns, Lead Product Development and Testing Technician; Voltaic Systems

  • Image: Jeff Crystal is on the right, Phil Stearns on the left
How did you get into electronics/engineering and when did you start?
  • Jeff: I majored in biomedical engineering at Tulane, which had a big circuits component, but I really wasn’t able to put my degree to use as I went into management consulting and then software startups. One of the joys of starting with Voltaic was the opportunity to get hands-on again with electronics and physical devices.
  • Phil: I was always curious about electronics and started tinkering with one of those Radioshack 30 in 1 electronics labs in grade school. Most of that curiosity, however, was sated by opening electronic devices and prodding about their insides. Putting them back together in working order, though, was a whole other story. I gained all of my knowledge of basic theory when studying engineering physics at the University of Colorado at Boulder, before transferring to the Denver campus to study audio engineering, where I explored the practical applications of that theory in music production.
Whats fun about solar?
  • Jeff: It’s like flying. You know technically how an airplane functions but every time I take off from a runway, I’m like, “Wow, this really works.” It is the same thing with solar. I use it every day, but when I take a solar panel and connect it to a battery or a device or a light and it powers it up, I get a little thrill. Luckily, learning to use solar is a little easier than learning how to fly.
  • Phil: It is incredibly liberating to realize that it’s possible to generate power without having to plug into a wall. I have the most fun dreaming up creative ways of integrating small-scale solar in sculptures and other artworks. Teaching solar is a very rewarding experience too.
What are your favorite hardware tools that you use?
  • Jeff: For what we’re doing, a multimeter or two is really the everyday tool we depend on.
  • Phil: I really like the Array 3710 programmable load and the Array 3644 programmable bench supply. The two in combination allow for detailed analysis of battery charging and discharging characteristics.
What are your favorite software tools that you use?
  • Jeff: This may sound funny, but we use PowerPoint all the time to draw up specs on all sorts of things. For the most part, we’re not doing circuit level design, we’re specifying the physical design and the behavior. It allows us to work really quickly to build specifications on a wide range of components.
  • Phil: I’m a hardware guy.
What is the hardest/trickiest bug you have ever fixed?
  • Jeff: For me, it is the actual manufacturing of components. We’re dealing with over 15 suppliers and we’re trying to work with them to make the highest quality components. Even with simple components like a phone adapters that you’d think should have zero problems, it turns out that sometimes the supplier solders a bit wrong, so it breaks if you bend it too far. We’re constantly getting samples, trying to break them, and making suggestions on how to manufacture them for better durability. I’d love to say that we have “fixed” this, but the reality is that we will always be making improvements to our components.
  • Phil: Charging Apple products is a tricky affair, and it took a bit of reverse engineering and conversations with our suppliers to figure out. All the Apple products charge using OEM cables and docks, most of which plug into an AC power adapter via USB. What we learned was that all four pins of the USB connector are used to communicate to the Apple device telling it how much power it can draw, and these vary by Apple device. For the time being, we seem to have it all figured out, but with Apple constantly upgrading its products and changing its standard, who knows how long it will be before we have to figure it out all over again.
What is on your bookshelf?
  • Jeff: A lot of books on economic development, plus too many Nordic mystery novels. I use the Web for most of my engineering information.
  • Phil: A healthy mix of electronic references, critical theory, sound and art theory, modern physics, and gardening books: A well worn copy of “The Art of Electronics” by Horowitz and Hill, several different selections from Don Lancaster’s “Cookbook” series, Baudrillard, Virillio, Zizek, Agamben, John Cage’s “Silence,” Harry Partch’s “Genesis of a Music,” “How to Imagine” by Gianfranco Baruchello, and “The One-Straw Revolution” by Masanobu Fukuoka are just a few of my favorites.
What online resources do you use (besides EEWeb of course)?
  • Jeff: I spend a decent amount of time on Adafruit.com—sometimes for their technical explanations, which are simple, but written very well. I also look to them as a model for sharing information I’ve learned about almost anything, and sharing it with the world. We’re not as good as them at this and might not ever be, but we really love how open they are about sharing and teaching.
  • Phil: Google. Whenever there’s a part (especially ICs) that I encounter in the field that I’m not familiar with, I pop the part number into Google and can usually pull up a datasheet a few clicks later. Wikipedia is also good for refreshing my memory and filling in any gaps in knowledge. If the answers aren’t in either of those places, I tend to turn to the books.
Do you have any tricks up your sleeve?
  • Phil: Unrelated to my work at Voltaic, I circuit bend devices (intentionally short circuit components) to induce erratic output. It’s an anti-engineering approach to producing art with electronics. You can see some images I’ve produced with low resolution digital cameras here. Because we as a society haven’t fully dealt with the end-of-life issues of our electronic devices, fully functional machines can be found on the street awaiting trash collection. These discarded electronic devices are becoming fodder for a growing art movement that involves using them as raw material for creative projects.
What has been your favorite project?
  • Jeff: Recently, getting our iPad solar charger out was a lot of fun. There are a lot of people doing things around phone charging, but no one had really done anything close to the right design, performance, and price for tablets. On the engineering side, there were a lot of tradeoffs about cost, weight, charge times, and device compatibility we had to think through. I think we’re happiest when we can be building products that no one else is.
Do you have any note-worthy engineering experiences?
  • Jeff: The first time that we connected one of our batteries in development to a device and the battery started smoking. I think we all learned the importance of over-discharge protection at that moment. We also got more formal on the battery testing process to make sure the things we specified actually made it into the product.
  • Phil: When I took on learning how to build my own bench supply, I connected my first linear supply circuit to the mains, and almost immediately both of the large filter capacitors popped and started venting a noxious smelling smoke. It took three days and several cans of air freshener for the smell to go away. It was an important lesson in double checking electrical connections and matching component specs to project demands; a postmortem examination revealed that I had wired the transformer backwards!
What are you currently working on?
  • Jeff: We’re working on solar LED lighting. LEDs are getting more powerful and cheaper. And to some extent, so are batteries and solar panels. This means that it will become economical for a safe, clean lighting source to replace unsafe, dirty, and expensive lighting sources like kerosene across the globe.
  • Phil: A big project that we’re coming close to finishing is our line of laptop chargers. We’ve been tweaking designs for optimum efficiency charging from solar, as well as making sure the batteries can supply power for the most demanding laptops on the market today. We hope to release our new high-power systems in the fall. On the low power side of things we’re taking on NiMH battery charging, and are developing a AA battery charger optimized for charging from solar.
What direction do you see your business heading in the next few years?
  • Jeff: We think there is a conversion happening from AC to DC. If you think about LED lighting as well as our phones and tablets (becoming the defacto TV), you can power a lot of things in a home without AC. From a solar perspective, this means you don’t need an inverter. You don’t need a big lead acid battery. You need a small to moderate sized solar panel and a compact lithium-ion or lithium-polymer battery. We think this will make the economics of solar much more effective and practical for low and middle-income families around the globe.
What challenges do you foresee in our industry?
  • Jeff: In consumer electronics, size and performance are always an issue. People want things smaller and cheaper. The issue is that solar cells really haven’t gotten that much more efficient. So when people buy products with a tiny little solar panel on it, they may think it is cute but the end result is that it just doesn’t work that well and they end up souring on all of solar. I think properly setting expectations and educating masses of people who have been trained on plugging things into perfectly functioning wall outlets on how to use solar will take some time.

I think the other challenge will be dealing with end-of-life issues. In a decade or so, there will be a lot of solar panels and batteries that have stopped functioning properly. Are these recycled properly? Can we recover the value from them. I don’t think that has been worked out.

  • Phil: The challenge of educating people is a major issue. I see the portable solar market as a path toward marketing larger utility-based approaches to solar energy production. If many people are having poor experiences with portable solar charging, then that will inform their attitudes toward proposals for larger scale installations in their communities. Sadly, not all of us are convinced that solar is worth the expense, otherwise we’d see panels covering rooftops and southern-facing office buildings everywhere. Ultimately, the larger scale utility-focused installations are where solar’s greatest potential lies. Making solar portable means that people will carry it with them, which is great, except that we spend much of our time indoors. This means the resources used in making portable charging systems are not being utilized to their maximum potential. Permanent outdoor installations will gather and convert solar energy whenever it’s available rather than only when availability and circumstance intersect to place the user of portable solar outdoors during a sunny day. In addition to being able to charge on the go (while biking to work), plugging devices into outlets powered by panels on the roof makes sense. A challenge I see is integrating portable solar products with grid interactive systems so that every little watt has the chance to add up.

Additionally, the manufacturing processes used to make portable solar resilient and durable also contribute to the end-of-life issues. Monocrystalline and polycrystaline silicon are easily recycled, but not if they’re encased in epoxy. Newer, more efficient thin film solar appears to satisfy the durability requirement when mounted on a suitable substrate, but will also have to address issues of recycling, especially due to the increased use of exotic materials. As Jeff said, there is a lot left to be worked out when it comes to dealing with end-of-life issues.

What are you doing on the environmental side of things?
  • Jeff: In addition to the big idea that we’re helping people generate their own power and helping them create street-level conversations about alternative energy, the biggest change in the production of components of the last few years has been RoHS standards. We select suppliers who comply with RoHS and require it any place it applies. We’re also trying to get more of our own components back in-house from customers so that we can reuse or recycle them properly. I think we can get a lot better here though.

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