Screaming Circuits: General interest


If there was a lot of twittering going on, I think I'd call it "flutter." I could call it "a bunch of Twitter tweets", but that's too long and awkward, so I'm good with flutter. Probably because it's short and rhymes with clutter. If there's really a lot, then we could call it flutter clutter.

Regardless, I'm still in my quest to determine if Twitter really does have a use that matches up with something I might need or find useful. I'll just take a few examples. What I'm finding is, in addition to the "I ate a cheeto" noise, there seems to be useful information. I regularly pass through a fair number of websites, but there are more that I would like to keep up on.

If the website owner does a good job, I can keep posted on their doings and I can know when I need to pop over for more detail. Adafruit is a good example of that. I'm not currently in the market for anything they sell, but they are one of the most influential members of the open source hardware community. By following them on Twitter, I can just glance at their announcements quickly and quickly jump over if I want more detail. That works pretty good for keeping up with the OSHW folks. I have a number others that I follow for similar purposes..

I also like to keep up with the mood and mindset of the engineering community. I read the trade magazines (or their websites) but there is more to it than that. I don't follow many periodicals because the volume of tweets tends to be too high. I have few (SilconFarmer, Chris Gammel, Mighty Ohm and freaklabs) that I follow specifically for that purpose. That's useful.

MaxMaxfield AKA Max the Magnificent always has interesting things to say. Some just his own thoughts and some teasers for interesting articles he's written over on the eeTimes website. And he posts just about the right amount. Enough to be worth following but not so much as to become noise. Mike Buetow over at Circuits Assembly magazine does a very good job of keeping me informed about what's going on in the EMS industry. Very valuable.

Okay, so that's not everyone I follow, but it's three different types of Twitter streams that I follow and find useful. I think that means that whether I like it or not, I do seem to be finding use in all of the flutter clutter. I won't call myself completely sold yet, or even a Twitter fan, but I may be getting there. I still do my best to avoid the "Cheerios are good" crowd.

That's three uses. Any other good uses for it in the technical community that I've missed?

Duane Benson

So Long Old Friend

Just watching the final shuttle launch and pondering a few questions.

A significant number of innovations came out of the Mercury, Gemini and Apollo programs and filtered down to public life. Some were in materials, some were in electronics, some in software algorithms  and some in other technology areas. It was pretty much all new back then. When the shuttle was first being developed back in the 1970's, innovation in materials and other areas came about as well, though it did use a fair amount of recycled technology in the beginning.

But since that time, have there been any major breakthroughs directly from the shuttle to filter down? Though it never lived up to the "one launch a week" billing, it did, in a sense, become the space "truck." Sort of an old pick-up truck. Not much new. The occasional upgrade. The occasional breakdown. But mostly just there hauling stuff around.

When the next manned launch vehicle comes out, will it deliver a wealth of innovation as did the first decade of manned space flight? Or will it be designed with primarily off-the shelf or near off-the-shelf technology?

In the 1960's, private industry benefited greatly from the research that went on in the space program. I suspect that the next time around, whether it's a NASA design or a commercial design, it will be the other way around and the space vehicle will benefit from research paid for by commercial activities.

Duane Benson
Thanks for all the fish

Loopy Ground Loops

A while back, I posed a question about using flood fill (AKA copper pours). I've been reading a lot about ground loops lately which brought me back to that original question.

LED scroll ground plane Some people suggest segmenting your ground plane between analog and digital sections. Some people suggest segmenting the ground plane for individual critical ground return paths. The follow on to my original question is: On non-exotic designs does segmenting ground planes really help? There's actually two questions, with the second being: At what clock speed does it make sense to start worrying about issues caused by ground return paths / ground loops? There are probably more questions. Those are just the two rattling around in my head at the moment.

Interestingly, though, when I wrote the original post, there didn't seem to be a clear "most common" between pour and no pour PCBs. Today, I'd have to say that the majority of designs we see here at Screaming Circuits do use flood-fill ground planes, either internal or external.

Duane Benson
You can solve ground and noise problems by just not hooking up power

Bouncing BGAs

I dropped my cell phone on the pavement the other day. That's bad enough, but in my instinctive attempt to catch it, I actually hit it and increased it's downward velocity. Luckily, everything still works. The odd thing is that I just assumed that it would still work. No real questions or doubts on that thought.

That realization got me thinking. (it happens now and then) What other devices do I have that I automatically expect to survive a drop onto concrete? I have a carpenter's hammer. I expect that to survive a drop intact. I would not expect my camera to survive such a drop intact, and have empirically verified that fact. A little car GPS? Probably not. Laptop; uh... no.

I'm sure there are some other devices that would easily survive. I just can't think of any off the top of my head. I suspect that there are a lot of factors that go into making cell phones survivable. The case, the overall mass, the quality of solder joints.

Along those lines, some folks use an underfill glueish type substance to hold their BGAs more securely. Some designers use pick and placeable solid underfil. Some just rely on extra good soldering and some leave it to luck. Of course, not all BGA installations require much shock resistance. How do you secure your parts when shock or vibration are serious concerns?

Duane Benson
Quick, where's Henry? I need an inductor.

Hi Ho. Hi Ho. It's off to Scone I go

I found this video over on the adafruit blog. Asimo, by Honda, is cool. Mars rovers, by JPL, are cool. Packbots, by iRobot, are cool. But, for robots to really take off, they need to be able to run down to McDonald's and buy some Big Macs or saunter on down to the Latte shop and pick me up a 16 oz non-fat Latte while I stay at my desk and keep working. Maybe hop out of the car and get one while I drive around because I can't find a parking spot. Donuts would be good too.

Now, that is a real robot. The only problem with the bot in this picture is that it needs a place to put the drink. Scones can be pretty good, but they tend to be kind of dry for my tastes without a drink to go with them.

Duane Benson
Watson - come here! Find Juan Valdez and ask him where I can get some coffee.

Twitter, What is it Good For? Absolutely 555contest

I follow a few people on Twitter. A few people follow me on Twitter.

A number of web sites have engaged their readers in debates about the usefulness of Twitter (and other social media) to engineers. In general, these debates are talking about hardware engineers. A lot of software engineers pretty much live on the Internet and will embrace or invent any new thing.

The overwhelming majority of the responses that I've read put Twitter in the class of "a waste of time." Not everyone feels that way, but there's quite a few who do.  I'm still in study mode. I can see how it can take up a lot of time if you don't exercise some self control and it has a weird partial-voyeur aspect.

If I'm following, person A and person B, I'll see any conversation they are having. Most discussions are undertaken with that in mind, but some start to lean toward the personal side. Now, if person C gets in the conversation with one or both of A and B, and I'm not following C, I end up 723px-NE555_Bloc_Diagram.svg seeing part of the conversation. It's a bit like listening to someone talk on the phone and hearing only their side. It's odd.

It can lead to interesting activity though. Recently, one tweeter, Jeri ( suggested a design contest centered around the old stalwart 555 timer. Chris ( picked up the ball with her and In about three days, just over Twitter, they organized it, other tweeters chimed in, sponsors offered prize money and they've set up a website for it. Fascinating.

If you're on Twitter, search for "555contest" to see the conversation in action. In any case, if you're a fan of the now 368 year old 555 timer, you might want to dig into the recesses of your brain for entry ideas. You can also follow Screaming Circuits on Twitter at "" and see for yourself if it's useful or too loaded with mindless drivel.

Duane Benson
Huh! Yeah!

0 or 1?

I've been running around telling people "Happy New Decade." Generally, such has been received with a blank stare or some comment related to me being sarcastic.

Back when we turned from 1999 to 2000 and again from 2000 to 2001, I heard a lot of controversy related to which year actually started the new century. Oddly, I haven't heard any of that this transition, even though the question is just as relevant.

I can certainly understand the two schools of thought on this. 01, 02 ... 09 all don't have a leading digit so they sound and look much different from something that does have a leading digit, e.g., 11, 12, 13... But, look closer at my first list. You don't see "00" in there. Certainly we did have a year "2000", but did we actually have a year "0000"? I've heard of the year one BC and the year 1 AD, but never zero BC or zero AD.

According to Wikipedia, which is never wrong, the Gregorian and Julian calendars do not have a year zero. Astronomical year numbering apparently designates 1 BC as the year zero. But "astronomical year numbering" sounds like a science thing and how many of the average population actually like to deal with "science things"?

If you're a digital person, maybe. Most arrays start with 0. Although some languages do start their arrays with 1.

But here's where I have decided to sit. I was one once. No one has ever said I was zero. I was also ten once and ten equals a decade. Although, decade counters do count from zero to 9. Again, in a purist digital world, 10 would start the new decade. However, for the most part, while machines operate in a digital world, people do not. On the other hand, as soon as I turned one, I had been on this earth for one year, so had the calendar been in existence for one year when year one started? If so, we would have had a year zero. People actually do have a year zero. Extra young folks are called one week old, one month old, etc. In that there is an implied zero and one month old. That is not the case with the calendar. Therefore, in my mind, 2001 - 2010 is the first decade of this millennium and 2011 is the start of the new decade.

So, happy new decade!

Duane Benson
Let's count it in binary next time

Open Source Mea Culpa or back pedaling? You decide

Last week I wrote about "Ten electronics things to be thankful for in 2010." If you're reading this now, you probably don't need the link because you probably read that article then too. But that's not really relevant. What is relevant is that in my #6, about open source hardware. I wrote, in part, that in some ways open source seems a bit exploitative of the designers. pt wrote in the comments for the blog article asking if I could give an example of how open source is exploitative.

I got to thinking about my choice of words and came to the conclusion that "exploitive" doesn't quite cover what I was trying to say. Although, in some cases, I think it does. It's possible that there are some aspects of the open source movement that I just don't get. Or it's possible that I have the capacity to pick a black cloud out of anything. If that's the case, I like to think that I can also pick a silver lining out of anything as well. That combination becomes a problem with recursion.

I'm a capitalist so I believe that (a) it's important to have profit as an ultimate goal of any commercial endeavor. I still have a bit of idealism left so I also believe that (b) when making that profit, we should be like the Boy Scouts and leave the planet a little better off than we found it. I get sick to my stomach when I read about executives making massive millions of dollars when their employees struggle to adequately feed and clothe their kids. (Is this post turning into one of those "I believe..." manifestos?) Following up that last point, I believe that (c) if someone does good work, they should get something in return for it. It's a trade. You give me something valuable and I'll give you something valuable in return. Not always money, but something of value.

That's where the mushiness comes in for me. Here's the good side. Ti is a big company that, with the Beagleboard, is giving something of great value to the electronics design community. As far as I know, the people at Ti working on the project are paid. My guess is that the ultimate motivation of Ti is it to help sell chips, but the project has given a whole lot of people access to a level of performance whom would not have had access it otherwise. That endeavor meets my abc conditions. Companies like Adafruit, Sparkfun and DIYdrones have built successful small (and growing) businesses with the help of open source hardware and software. People are making a living (I assume) from those organizations. Both companies give a lot back to the community and both companies make it very clear that they benefit from and really appreciate the efforts of open source designers. They give the folks recognition and support. They and companies like them meet my abc.

The other side of open source, and where I smell the exploitation, is when big companies use open source, make large profits and don't return anything. I mean, sure, the licence allows them to and I suppose that by reducing their costs, they can be more competitive and stay in business, keeping their employees employed. But when a software company buys the remains of another company or two that allegedly "own" some opensource code and then tries to make a business of suing people that use that open source software; I consider that to pretty exploitive of all of the people that voluntarily gave their time to the project.

When a large muti-national company that sells server farms uses an open source OS and doesn't return anything to the designers, I find that also to be exploitive. I don't know what the answer is. I mean it's cool that Linux, for example, is used in so many places. The fact that big corporations put so much weight on it certainly validates the legitimacy of it. But I can't help but envision open source developers out there, that could really use a bit more money in the bank, looking at those big corporations that are profiting off of their backs, feeling a little used.

So, am I missing something? Do I not get it?

By the way, this piece has a lot of personal opinion in it, but I do believe that my company works hard to meets my abc so I don't have a problem posting this on my work blog. The two times in my career that I did work for companies not meeting my abc, both ended badly for me. Fortunately, I believe in this one.

So, help me out here. If I'm not getting a part of this, feel free to chime in.

Duane "Does idealism hold up in the face of reality?" Benson

Need a Reference for the Reference

Not long ago, I wrote a short post about non-standard use of reference designators. After doing that, I've been looking at some of my own microcontroller and motor driver boards with an eye for how close to standards I am.

All of the R's, C's, D's and U's are okay, but there are some differences. For example, the Eagle library I've been using calls crystals "X" instead of the more standard "Y." I have seen crystals designated as "X", "Y" and "Q." LEDs seem to go by "LED" instead of "D" as indicated in the Wikipedia list. Headers go by "J", "JP", or "H." Wikipedia says "J" is for a female jack connector, "JP" is for jumper, and it doesn't list a "H." My board has break away two-row male headers and keyed single-row male headers. Wikipedia does note that its list is a set of commonly used designators. Not necessarily standard.

We probably do have the specific standards document laying around here someplace, and if I were doing real work on a professional basis, I'd hunt it down and make sure I followed the actual standards. But I'm not doing real work with my controllers and drivers, so I just do the best I can. I wonder how often that happens everywhere. The standards books are "somewhere" but no one really knows where.

Duane Benson
Somwhere over the reflow...

Spam, Spam, Eggs and Spam

I normally expend most of my writing words on challenges our customers and other engineers might face in their day to day design and layout activities. But not today. Today, it's about a specific challenge faced by your typical blogger. Off and on for the last couple of weeks, I've come into work in the morning, opened up the blog and found three spammy comments. Here's today's three"

"Compare to the majority of the other blogs, your site tend to be so fantastic. Therefore nice to examining the post. If I've a probability, I would like to research along with you because I think that my potential haven't yet achieved the excellent amount."

"You may remember the three proverbs: Laugh, and the world laughs with you; Weep, and you weep lone. Life is measured by thought and action not by time. Long absent, soon forgotten."

"You may remenber [sic] the three proverbs: Laugh, and the world laughs with you; Weep, and you weep lone. Life is measured by thought and action not by time. Long absent, soon forgotten."

Now, it is a bit flattering to hear that my site tend to be so fantastic. Not just "fantastic", but "so fantastic"! But perhaps the subject matter could be a bit more on topic. The author noted that if he have probability, he would like to research along with me. I could always use some extra help, but I don't have any probability to pass on. Perhaps a call to Zaphod would be in order.

I'm not sure I agree completely with the second supposition. I'd bet that a lot of unemployed or underemployed folks are weeping right now. Probably enough that they could be considered to have a world weeping with them. I know I would. I'm also not sure what the deal is with the third one. That author just copied from the one above it. How rude.

All is not always as it seems though. After reading these this morning, I did as I always do and fed the three comments into my netlist confabulator. It turns out that the text in these three comments is actually a turbo-encoded form of the design of the Constellation spacecraft. If I had checked the IP address prior to marking the comments as spam, I wonder if I would have found that this is a desperate rocket scientist tying to smuggle his decade of work home before the lights go out and the servers get recycled.

Duane Benson
Have you got anything without spam?