Blog - Screaming Circuits


Electronics Swarms - Overhangs

20160229_144328As I've stated many times before, we see many, many different jobs go through our shop. In those jobs, we see some of the absolute newest components and packages; some not yet available to the public; some are so R&D that they never will be available outside of a lab. We see the best of the best in terms of design practices and complexity, and we see many that aren't so much in that arena.

Given that, it would seem logical that the design problems we see would be pretty much scattered all over the map. By some measures they are, but on a day to day basis, they tend to cluster. For a few months we'll see a lot of QFN footprint issues. In a different few months, we'll see a lot of via in pad issues, etc. I don't know why. It just works that way - problems come in swarms, or storms.

The latest swarm relates to panelized boards and components that stick over the edge of the board. We build things like that all the time. The problem comes in when the panel tabs come out right where the component overhangs. If the component overhangs in the cut out area, it's usually not a problem. However, if the component is on the connection tabs, we can't place that part without first depaneling. 20160229_144238

Probably the most common example is the surface mount USB Micro-B receptacle. It over hangs the board by a small amount, and that overhanging part is actually bent down. If it's at the tab, it won't even mount flush. Take a close look at the images along the right. That connector won't mount as it's sitting on a tab.

So, what do you do about it?

You can have your boards made as individuals. Although if you want short-run production, or if the boards are really small, that might not 20160229_150126be possible or practical. You can also talk to your fab house about it. They may be able to place the tabs in a spot that won't get in the way of the overhanging part, of they might be able to tell you where the tabs will be, allowing you to keep clear in your layout.

Duane Benson
Anyone ever drink Tab Clear?

An Electronic Business Card Holder

I design and build electronics at home, late at night when the spiders are out, and by day, I put my hours into Screaming Circuits. My job here doesn't involve building things. I'm the marketing department, but I like to keep as much manufacturing smeared all over me as is possible. Here's one way I do that.

20160226_100559

Business cards are a bit of an anachronism today. I don't give out many, this being the 21st century and all, but I still need some on my desk - I guess to look businessy or something. No one's ever given me a cheap card holder with their logo on it, and I don't want to just scatter cards around. So, why not combine my need to display business cards on my desk with my compulsion to create electronic things? With that thought in mind, I decided to build an electronic business card holder. Of course, I first had to decide just what an electronic business card holder would be.

Here's what I came up with:

  • It should be small, about the size of a business card
  • It should have a lot of blinky lights
  • It should do something when a card is removed
  • It should have a long battery life
  • It should use tiny parts to show off our manufacturing capability a bit
  • It should be 100% buildable within our electronics manufacturing process (meaning it should be just electronics; no bolts or case)

That's not a long list, but does involve a few decisions. I'm pretty familiar with Microchip PIC processors, so that would be a logical choice to drive the thing. Arduino compatibility would be cool, but I'd have more trouble with battery life, and 20160226_095148the PIC microcontrollers come in some pretty inexpensive forms.

I'd recently been using a variant of the PIC18F46k22 on another project. I comes in a 5mm x 5mm QFN package and can be purchased for less than $3.00 in small quantities. it has plenty of I/O and can be set to a very low power sleep mode. I settled on that MCU and a CR2032 coin cell battery for power.

20160226_094829Rather than add any extra hardware to hold the cards, I came up with an arrangement of pin headers and small push-button switches. (as in the photo on the right) One header is the six pin Microchip in circuit programming (ICSP) header, and the other is a six pin I2C/SPI header. Not that I need I2C or SPI, but with that, you could turn this into a robot business card holder or something.

I considered a light sensor to detect when a card is being picked up, but that would require leaving the A to D powered up, and it would be less reliable due to changes in lighting. I looked around my junk box at home, and found a Freescale MMA8452 3 axis accelerometer in a 3mm x 3mm QFN package. It also has a decent low power mode, and can be talked to over I2C.

19 GPIO pins remained open, so naturally, I had to put in 19 LEDs. Stay tuned for my next installment, where I'll go through some of the design decisions. At the end of this series, I'll be giving out ten of these, so stay tuned to see how you might be able to get one.

Duane Benson
If you dreamed you saw the silver spaceships flying
That's a okay. They're RoHS compliant

Raspberry 6.283185307 Zero

AKA, A second post on the Raspberry Pi Zero.

It's been two months since the release of the $5.00 Raspberry Pi Zero, and I still haven't been able to buy any. As I discussed in my prior blog about it, there is plenty of discussion around the fact that, out of the box, it's not real useful without adding enough accessories to make it as expensive as any other Pi model. I certainly understand that point, but here's another way of looking at it.

If you want to learn software, buy one of the other Pi models. If you want to learn about hardware design, buy the Pi Zero and download some CAD software. Then go online and get the Pi Zero dimensions and start designing accessories for it. You can start with one of the many open source Pi Zero accessory designs, or come up with your own. Don't look at it as a system that's missing too many parts. Look at it as a base for a different type of learning.

One of the scariest things about designing a plug-in/on board for a bigger computer is the possibility of a mistake that will fry the expensive board. With the Pi Zero, you're risking $5.00.

Like I said, I still don't have one, but I've drawn up my for Pi Zero accessory:

PiZero LiPoly

It will plug right on to a Zero as a rechargeable Li-Poly power supply. Not at all a complex circuit, but it's only the first in a series. As a small board, it doesn't cost much to get fabbed, so for about the price of one PCB sized to fit the bigger Pi boards, I can get two of these.

Next, I'll design a motor driver, and then possibly an IMU, or sensor board.

Duane Benson
If you have your Pi calculate Pi, would that Pi be Pi enough for Pi?

UPS and the Weather

The weather's just fine out here in Oregon. Well, that depends on your exact definition of "fine." It's raining out here and I'm not sure it will ever stop.

But that's not the point. Parts of the East Coast are bracing for a big winter storm. In fact, UPS has sent out a warning of possible shipping delays (read it here). Given that we ship primarily with UPS (and I'm sure other carriers will be just as impacted), there may be some weather-caused delays in getting your board to your doorstep.

UPS will do their best, and hopefully you'll get everything when you need it.

616px-Blizzard2_-_NOAA

Language dialects for the engineer entrepreneur

Much of marketing can be summed up with the word “communication.” It's communicating about a product or service, about wants and needs, or the past and the future. Good marketeers take this to heart and work hard to understand their market. But, it's more than just understanding the market; it's understanding all aspects of their language.

Wrong footprintI often talk about the language, or dialect, that people use. When I do, I'm not talking about English English vs. USA English. I'm talking about the difference between hearing and speaking; or between reading and writing. And I'm talking about that within the same person. Knowing the difference is often the deciding factor between winning or losing this game.

Speaking of games, in baseball, right handed players catch the ball with their left hand and throw with their right. Lefties do the opposite. Except me. Baseball was always difficult for me because I both catch and throw with my right hand. It slows things down considerably when you catch the ball in your right hand, take it out of your glove with the left, drop your mit, hand the ball back to your right hand, throw it with your right hand, and then pick your mit up off the ground.

In the same vein, a lot of people speak and listen in different dialects. Like the baseball, information comes in one way, and goes out another. If you don't plan your communication with that in mind, your conversation may go over about as well as I would as a shortstop in game seven of the world series. The thing is, most people don't realize that they do this. It's a perfectly normal, but often not recognized aspect of human communication.

Is it “form over function” or “function over form”?


Case in point, electrical engineers. Material written by a typical engineer is detailed, accurate, comprehensive, and often barely readable by anyone but the author. A common phrase heard in the technical world is that the content is what's important, not the spelling or grammar. An interesting contradiction is that engineers are often the quickest, harshest, and most pedantic of the “grammar police” that toss flame around in the social media world when someone chooses the wrong member of the set “there, their, or they’re.”

I maintain that both statements: “it's form over function” and, the counterpoint: “it's function over form” are incorrect. The correct maxim is: “form can’t get in the way of function.”

Form works with engineers. It works with everybody. Good advertising works with engineers. Where marketeers run into trouble is when they consider form to be too important, and they obscure the message. The reverse, putting too much weight on function, and not enough on form will be just as ineffective.

Engineers getting into marketing, either as an entrepreneur, for their own startup, or as one moving from a technical job into one that requires a lot of writing, need to pay special attention to this phenomena. You can’t write for yourself.

Anyone, not just people in the same technical field, should be able to read good writing. They may not understand all of the technical details, but they should be able to comfortably read and feel a sense of organization. Order, structure, and simplicity are important, regardless of the intended audience. My recommendation is that you have someone, with a lot less knowledge of your subject than you have, read your material. If they can get through it, you’re at least on the right track.

Duane Benson
Do you speak MBA?
Do you speak EE?
Are you an interpreter?

Predictions For The End of the Decade

Half a decade ago, back in January 2010, I wrote up a list of predictions for the end of the decade. You can read that list here. It's still 2015, so I can plausibly say that we're half way there, which is a good time for a status update.

0000: In 2010, I said: By the end of the decade, 50% of all passives will be embedded passives and 20% of all PCBs will have 90% or more of their passives embedded.

In 2015, I say: This doesn't look to be coming true, but it still might. As mobile devices and wearables get smaller, or more powerful, more electronics will need to be stuffed in progressively smaller areas. Those passives need to go somewhere. That somewhere could be into the PCB, or into the chips. I think the PCB is more likely.

0001: In 2010, I said:By the end of the decade, Quad stack POP (package on package) will be commonplace.

In 2015, I say: Quite likely. Double layer POP is showing up on low cost devices, like the $5.00 Raspberry Pi Zero. If it can go there, it can go pretty much anywhere. It won't be long before double stacking won't be enough. Although, the layers may end up being inside the chip package, rather than individual chips as layers.

0010: In 2010, I said: By the end of the decade, Each individual human will have their own IP address. Several of us will have more than one. That way, we can jury rig accelerometers into our hands and feet so we can wirelessly know where each of our extremities are at all times. Cats will have them too.

In 2015, I say: Yep, and then some. I already carry one in my pocket. In five years, we'll likely see personally assigned I.P. addresses that won't be device dependent. We'll be able to buy I.P. enabled clothes, like gloves, which will do a lot more than just know where each finger is. The pet ID chips that today, use NFC, will be available in wireless Internet connected versions.

0011: In 2010, I said: By the end of the decade, solder paste will be used less often than not when assembling components on to PCBs.

In 2015, I say: We will be seeing welded copper, additive embedded 3D printing processes, conductive glue, and other non-solder methods of assembly, but nowhere near to the degree I was thinking back in 2010.

0100: In 2010, I said: By the end of the decade, nearly all hydraulics and pneumatics in new motor vehicles will have been replaced by electrics.

In 2015, I say: This is already well on the way. With electric and hybrid electric cars growing in numbers, and with weight and fuel mileage being such a concern, this has to happen.

0101: In 2010, I said: By the end of the decade,the first semi-autonomous passenger vehicle will be on display on the auto-show circuit. Hobbyist built semi-autonomous cars will already be on the road.

In 2015, I say: I may have missed the boat on this prediction, in the pessimistic direction. Part of it has already happened. I haven't yet seen hobby kits, but most of the major car manufacturers have shown models. Tesla has a really good driver assist "auto pilot", and is promising fully autonomous vehicles for sale within two years of this writing.

0110: I said: By the end of the decade, "airline pilot" will generally be a really, really, really boring job. That's a bit of a problem.

In 2015, I say: The necessary level of automation required for this prediction to come true is already installed in most airliners. The only real question remaining, is how long before it changes from "Pilot primary, systems secondary" to "Systems primary, pilot secondary."

0111: In 2010, I said: By the end of the decade, most military "foot action" will consist of two soldiers in command of a squad of robots and those two soldiers will as likely be in Fort Lewis, Washington as in the combat zone.

In 2015, I say: Sadly, I still think this will happen. Not sad that fewer humans will be shooting and getting shot, but sad that we as a species will still consider war important enough to be throwing large quantities of money and resources at.

1000: In 2010, I said: By the end of the decade, the president of the US will be promising health care reform as the highest priority.

In 2015, I say: Yep. The president, presidential hopefuls, senators and representatives will still see this as a hot issue. One side will be trying to make quality healthcare more accessible, the other side less. One side, more publicly funded, the other side, less. I'm not really sure which side will be doing which, but I'm certain that each side will say they want to fix it and the other side wants to destroy it. Ugh.

1001: In 2010, I said: By the end of the decade, routine bioengineering will be, well, routine. Very scary.

In 2015, I say: I'm not so sure about this one. When I wrote it, I was thinking that home bioengineering would be happening and a class of bio-hackers would be emerging. That may still happen, but it won't be common. Governments, agriculture, and medicine will be doing a lot more of this, but I'm not sure the term "routine" will be accurate.

1010: In 2010, I said: By the end of the decade, the 2019 recession will be looming large and all of the people that have forgotten about the 2009 recession and the 2001 recession and the 1985 recession and the 1975 recession... will be freaking out again.

In 2015, I say: Is there any doubt? Does this ever not happen?

1011: In 2010, I said: By the end of the decade, lead will be gone from 98% of new electronics. Bummer.

In 2015, I say: Exemptions are going away. This will happen.

1100: In 2010, I said: By the end of the decade, four of the substances that replaced the substances removed from electronics due to ROHS and similar regulations will have been found to be significantly more harmful to the environment and the people recycling the materials than are the substances that they replaced.

In 2015, I say: I was being tongue-in-cheek, but it still might happen. The only caveat is that if it does happen, the data will be so obscured by politics, that it likely won't be possible for anyone to come to an informed opinion.

1101: In 2010, I said: By the end of the decade, the world of intellectual property will be in even more of a mess than it is today. Virtually everything will be accessibly for easy theft and cheap replication. (this is pretty much a big "duh")

In 2015, I say: This is still well on the way. Any industry that designs things will need to adapt to keep competitive. The patent world will still be a mess. Copyrights will be more of a litigation attack weapon than a protection tool. The best defense against pirates will be faster innovation. On the positive side, a lot of I.P. sharing will be intentional (by the inventor) and many businesses will be built based on collaborative innovation.

1110: In 2010, I said: By the end of the decade,building your own mutli-purpose robot will be as easy as building your own PC was in 1988. Hardware components and operating systems will be off the shelf, but standards will be pretty loosely defined, interoperability will be more theory than reality and applications will be sketchy and buggy.

In 2015, I say: This will happen, but it may be a little later than the end of the decade. The technology will very much exist for this to happen, but the capability of the hardware will probably be advancing so fast that even the limited amount of standardization needed for this won't be possible.

1111: In 2010, I said: By the end of the decade, still no flying cars and personal jet packs, dadgummit!

In 2015, I say: And, still no real hover boards.

Duane Benson

The Common Parts Library

The two most common causes of delay in small volume manufacturing here at Screaming Circuits (and presumably, others like us) are component availability, and footprint mismatches. 

Trim pot wrong footprintWe don't substitute parts without your approval for a number of reasons. I've written about those reasons a few times before. (Here, here, and here)

Incorrect footprints can lead to a host of headaches as well. (Read more here, here, and here)

Until recently, I haven't seen a lot of progress toward solving these problems for the hordes of engineers that don't have big support departments at their disposal. In fact, with the proliferation of newer, and small, component packages, and evolution of the supply chain, it's really gotten worse.

However, there are a couple of Knights in Shining Armor riding in to try and solve both problems. The Common Parts Library (CPL), created by Octopart, aims to create a list of components with the highest probability of being available and staying available (there are no guarantees where component supply is concerned). Read more about the CPL in my article posted on Embedded.com.

The other exciting entrant is SnapEDA. SnapEDA has a massive, and growing, library of component footprints. I've used their footprints with good success for high pin-count devices, and other parts with complex packages. It can save a lot of time and give better confidence that all of the pins go to the right functions. Read about one of my success stories here, also on embedded.com.

Duane Benson
Map makers put fake roads in as copyright traps
These folks don't do that. Nice.

Raspberry Pi Zero - What's it all mean?

What could you. would you do with a computer that costs $5.00?

First, let me explain a bit. The Raspberry Pi, if you don't know, is a small, inexpensive single board computer designed by the non-profit Raspberry Pi foundation in England. Their mission is to make computer related education less expensive and more accessible to the masses. As a next step in that mission, they just introduced the Raspberry Pi Zero, with an MSRP of $5.00. So, you can buy a Big Mac, or a Pi Zero. You could buy some peanut butter, jelly, and a loaf of bread, Pi Zero_3_of_5_1024x1024eat that for the next five lunches, and buy five Pi Zeros.

Now some folks have complained that it's not very useful on its own. It needs a wall bug power supply, a micro SD card, a few cables, and a USB hub to connect a keyboard and mouse to.

That's true, if you want to use it as a full PC workstation, which you can. It runs the "Raspian" distribution of Linux. But, I don't think that's where the greatest potential for this thing lies. No, I wouldn't use this as a workstation. It's biggest potential, in my opinion, is as an inexpensive embedded controller.

It has I2C, SPI, and RS232 pins available, as well as plenty of GPIO. Attach a small daughter card with accelerometer, gyro, magnetometer, and GPS, and you've got a nice drone auto pilot. Attach a few sensors and a cell phone module, and you've got a remote data logger. What would you do with one of these?

Duane Benson
Little Jack Horner couldn't get a plum out of this pi.

An Engineer Entrepreneur’s First Brand Lesson

If you’re an engineer starting a business, do you need to worry about your business’s brand?

In a word: yes.

You don’t need to make a big project out of it at the start. It can be as simple as a collection of notes. But simple or complex, you really need to start right away. Doing so will make things much easier down the road. The nice thing is that you can get started quite small. You don’t even have to call it a plan. At this point, it can just be a vision. (If the word “vision” seems too buzzwordy, then just call it “a bunch of ideas”)

What is a brand?

A brand has a lot in common with a person’s personality and reputation. It’s close enough that you can think in those terms. And, think, you should. Think about what you would like people (customers, employees, friends, family, etc.) to think and feel when they hear your company’s name.

What personality do you want your company to have?

  • Are you mean and gruff?
  • Are you nice?
  • Quiet?
  • Loud?
  • Helpful?
  • Athletic?
  • Sedentary?
  • Reliable to a fault?
  • Usually reliable?

Will you strive to be perfect, just okay, or a bit better than “good enough”? Do you want people to see you as having the best technology, or the best price? Go on with questions like that. Write down your questions, and write down your answers. You can carry a small note pad and pen around, but I suggest that you use a memo application on your phone. You’ll always have it with you, and it’s quick and easy to use.

When you walk into a grocery store, look at the signs. Do they strike you as inviting, or cold? When you get new tires for your car, watch how you’re treated. When you order parts online, consider how easy or difficult the web site is to use. Will any of that, or something similar, apply to your business? If so, jot down a quick note about it. Make a note any time you see or think of anything that triggers thoughts of what you want your business to be like.

You’ll collect all of these notes and clean them up a bit. These will become your brand attributes. They are the seed of a brand for your company.

Once you have this seed, you’ll use it to guide business decisions – all of them. For example; if financially frugal is one of your chose attributes, you won’t go out and rent a big office with mahogany paneling. If you want to be seen as leading edge in the media world, you might buy Mac laptops instead of clunky desktop Windows PCs.

Every thing you do and say, all of the time; it is all part of your brand.

A few example notes:

  • Am I cheap or expensive? Neither – I just want people to feel like they got a bit more than their money’s worth.
  • What about flashy? A little, but only where relevant. I don’t want fancy boxes, but I want them to look befitting of new technology.
  • I’m selling to engineers in banks, so casual suits if I’m in the front office, but no suits when I’m not.
  • Do I want people to envy my lifestyle? No, I want them to see me as a crazy workaholic.
  • What about getting in touch with me? I don’t think phone support is necessary for all of my customers, but I think email should be answered within an hour.
  • Am I “big industry”? No. I’m nimble and “new economy.” I should get a small office in a recently gentrified part of town, instead of in a mid-city office building.

Keep going. It can be as simple as that. You can get more formal and organized with it later.

Veterans Day 2015

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To those who make and have made our freedom, our successes, our failures, our petty arguments, our philosophical differences, our explorations, our livelihood, our great discoveries, our day to day accomplishments, our freedom... To those that make and have made this all possible, the people at Screaming Circuits thank you.