Screaming Circuits: Industry


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?

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.

What is Personal Manufacturing?

There's a lot of buzz floating around these days, about "Personal Manufacturing." Screaming Circuits has more than a decade of bringing personal manufacturing to engineers. We pretty much started the category in the electronics industry, so we're quite familiar - but not everyone knows what personal manufacturing is. I'll do my best to describe it, and what it can do for you.

The short answer, is that personal manufacturing is building your boards on your terms, not on the terms of some nameless, faceless factory.

Vertical_markets
The longer answer is probably more useful. 

Traditional manufacturing is all about statistics and fractions of a penny. Those factors are important; especially if you're manufacturing millions. But, when you just need a few boards, or a few hundred boards, those factors can make your job nearly impossible.

With personal manufacturing, you can decide when you want or need assembled boards on your workbench. You won't need to beg for time on a busy volume manufacturing line. In the case of Screaming Circuits, it's cloud-based manufacturing so you can order online from your desktop, when you're ready, rather than waiting for someone to pick up a telephone.

With personal manufacturing; you design it, get some prototypes, make a few mods, lather, rinse, repeat. Then, you'll get a few dozen, few hundred, or few thousand, and start selling. You'll get what your budget allows and don't need to commit to minimum volumes, or long-term business. You can polish your design faster, with less hassle, and you can get to market faster, with less hassle. Faster to market and less hassle both mean more time and money for you.

NPI (new product introduction) has never been easier than it is with personal manufacturing. Years ago, I was a product manager at a start-up. The entire NPI process was a nightmare. Our engineers couldn't get anything built without half a dozen support staff. Someone had to make the documentation usable. Someone had to hunt down sample quantities of parts. Someone had to make sure the board would fit on the volume manufacturers' assembly line. It went on and on like that, taking up months of the design cycle. We were at the mercy or people who only cared about making their part of the process easier.

Rather than producing the quality product we wanted, our new products would be shipped to customers with mod wires. I recall one board that needed 64 mod operations before it could be shipped. Yes, that was on a released, shipping product.

With personal manufacturing, as Screaming Circuits provides, you can get a few prototypes built right away. If need be, you can modify, and get a few more built at your convenience. When the mode wires are gone, you can build up a hundred and get them out to customers without delay. It's not about what works best for Screaming Circuits; it's about what works best for you.

Duane Benson
Right now a personal pan pizza delivered to my desktop would work for me.

 

 

Manufacturability Index in practice

My prior blog covered the Screaming Circuits Manufacturability Index. It's something I'll be using from time to time when discussing new components I run across. I've got a few examples to put the numbers into context.

On the low side of the index, we have:

7400 TH1: Just about anyone could hand solder the part
Examples: Thru-hole parts

The SN7400 quad NAND Gate, shown on the right, is a good example. It's big, it's thru-hole, and if someone has trouble hand soldering it, they really need a few more classes.

Closer to the other end, is a new chip I've run across. The Silego GPAK4 is a small FPGA-like mixed signal device. It's got a number of analog peripherals, a bank of programmable logic, and the ability to configure it up the way you want. Take a look at it below:

GreenPAK4 cropped

This little thing is housed in a 2 mm X 3 mm QFN package. That's pretty tiny by the standards of my giant fumble-fingers. I've given it a rating of 4.b, on the Screaming Circuits manufacturability index. The number ranking "4" means: "Needs advanced automated assembly technique", and the letter suffix "b" means: "Typical level of challenge within the number rank." In other words, right up our alley.

Unless you posses super-human abilities, and maybe lasers in your eyes, you won't be hand soldering these. You'll have them assembled by us (or someone with the same technical capabilities as us), where it will be a standard process.

If you do want to put one or more of these in your design, you will want to make (or find) a custom library footprint for your CAD software. Due to the variable length pads, a standard one-size-pad footprint might lead to solder joint reliability issues.

Duane Benson
The chips go marching one by one, hurrah, hurrah
The chips go marching one by one,
The little one stops to suck her thumb
Just to see if the solder is lead-free

 

Screaming Circuits Component Manufacturability Index

Screaming Circuits Manufacturability Index

Ranks the difficulty of assembling a component. Index is one to five, with one being easiest, and five being the most complex

Sub index: a, b, c

    a: Not a challenge within the number rank
    b: Typical level of challenge within the number rank 
    c: Fits in the ranking, but likely needs special process, fixtures or attention

1: Just about anyone could hand solder the part
Examples: Thru-hole parts

2: Surface mount. Should be machine placed, but big enough to hand solder
Examples: 0805 or larger surface mount passives, SOIC packages

3: Pretty much any grade of surface mount equipment can handle this component
Examples: TSSOP or larger, 0.8mm pitch BGAs

4: Needs advanced automated assembly techniques
Examples: 0.4mm pitch BGAs or QFNs, CSP (chip scale package) or WSP (wafer scale package) BGAs, 0201 size passives, Package on Package (POP)

5: More or less R&D at this point. Few companies have or will assemble this part
Examples: 0.3mm pitch micro BGA, 1,700+ ball BGAs, 01005 passives

Just about everything 4b, and below are routinely within Screaming Circuits standard (guaranteed) process. 4c, 5a, 5b, 5c, are becoming more common here. These are special process (falling outside of our guarantee), but we can usually do a good job with them. You'll need to speak with a manufacturing engineer before placing the order.

Duane Benson
a colossal negative space wedgie of great power coming right at us at warp speed
Readings are off the scale, captain

Internet of Things Month

I’m not sure exactly when the term “Internet of Things” (IOT), was coined, but it’s become one of the hottest topics in the electronics industry. The IOT is all about connected devices, most small and independent; many from makers and new start-ups.

In the IOT of the near future, virtually every household, office, and personal device will be remotely controllable to some degree. And, it’s not just about control. Most of those devices will also sense conditions, respond, and communicate appropriately.

If you were to take a tour of our factory floor today, and compare it to a tour of a few years ago, you’d, of course, see more large boards loaded with complex components. You’d also see a lot more super small boards crammed with microcontrollers, wireless communications, sensors, and tiny parts. Many of them are no larger than a US quarter. Those are Internet of Things devices.

The number of different devices being churned out is staggering, yet is a trivial number compared to what we’ll see in the next few years. Scoff, if you must, but there will come a time when your favorite ball-point pen can let you know just who stole it off of your desk and where they've hidden it.

In honor of the spirit of innovation brought forth with the IOT, Screaming Circuits has declared April 2015 to be Internet of Things month.

A_small_cup_of_coffee 250You too may be able to join in the celebration by placing an assembly order during March 2015 and requesting our “Internet of Things Gone Bad” poster: a contrarian view into a possible dystopian world where humans have to argue with their clothes, coffee pots, and cars, before leaving the house.

If you places an order with us in March 2015, will get an email asking if you want out Internet of Things poster. Just reply in the affirmative, and we'll send it out to you.

Duane Benson
All things on the Internet are relative
All my relatives are things
My relatives took all of my things

Do you need PCB Assembly Services?

Do you need PCB Assembly Services, or do you not? That is the question. Well, it's A question. Just one of many, I suppose.

TI TPS62601 front and backOne of many, but it is a question just about every electronics developer needs to answer at some point. The answer isn't always yes, nor is it always no. The answer is quite often "It depends." I work here and I don't always have a clear answer to the question. I've sent some board through our plant, and have hand built a few.

For me, it comes down to a few options:

Use Screaming Circuits PCB Assembly Services:

  • Does it need to be done right?
  • Is time a consideration?
  • Are there too may placements for me to deal with?
  • Are there more than one or two boards?
  • Are the parts too small?
  • Are there any BGA packaged chips?
  • Will it be monotonous?

Build it myself if:

  • It's a no-hurry project.
  • The parts big enough.
  • It be fun.
  • It will be a valuable learning experience.

I can enjoy building up a board myself in the same way that someone working for a car manufacturer might rebuild cars at home as a hobby. 0805 passives aren't a problem for me to hand solder. I don't mind a small number of 0603's. I'll hand solder 0402's in a pinch. I've tried a few 0201's with poor results.

Forchips, I don't have a problem with SOIC's. I'm not bad with a TSSOP. QFN parts are a challenge, but some types have enough exposed metal on the side to solder. I really can't place BGA's, but I'm experimenting to see if I can find a way to solder small ones in my toaster oven.

With the impending advent of desktop pick and place machines, there will be a few more options, but the basic question will remain the same as it is with "build vs. buy" in any industry: "Which do I have more of, time or money?"

Duane Benson
Let's get small!

Does Anybody Really Care?

The upside of a visible identity is that people see you can might possibly care and understand. The downside, is that people can find you. Today, I'm sort of treading the line between the two.

I'm testing out some Twitter ads right at the moment. As someone that has a service to present, I have to do things like that. Ideally, it won't be intrusive and will just give information, but that's not the point.

One of the steps in putting together a Twitter ad is to select categories of Twitter users that might be interested in what I do. The process of picking those categories reminded me of something that's almost always annoyed me when I have to pick my categories for anything. Namely, my categories aren't there.

This particular ad, is sending people to eBay to buy (hopefully) a coffee mug with the Sputnik 1 transmitter schematic on it. We're doing it to help out our local FREE GEEK place. (Yikes! Three links in a row) Again, that's not the point here.

I'm thinking that electrical engineers would be interested, as would space fans. Well, those categories don't really exist. The have a major category: "Business." The closest sub category in Business is "Technology." That's somewhat close, but do engineers really want to be classified as in the business world?

 "Careers"; nothing close in the sub categories. "Education"; nothing close. "Events" has "Tech Tradeshows" as  a sub-category, but as with business, it's not really where I'd look.

"Hobbies and Interests"? Nope. They have "Astrology", but no hobby electronics.

There's the category "Science", but its subs look like chapter headings in a sixth-grade science book.

Wait! There's "Technology and Computing"! That looks promising... But... No. It's pretty much software and IT.

And, that's it. I see this sort of thing all over the place. Software, IT and businessy stuff get categories, but electronics design, embedded computing, robotics... Other than in the direct EE press, these types of categories just don't seem to exist.

Duane Benson
What time it is?

Open The Pod Bay Doors, HASL

Does anyone use HASL (Hot Air Surface Leveling) anymore? It's also known as HAL.

Prior to the RoHS days, HASL was probably the most common surface finish. You can get it lead free, but most boards seem to use immersion silver or ENIG (Electroless Nickel Immersion Gold). HASL has traditionally come at a lower cost than those other two finishes, but immersion silver can generally be found at the same price now.

Our friends at Sunstone.com, for example, charge the same for silver and tin/lead HASL. ENIG is still more BGA on HASL closeexpensive no matter where you go though.

One of the chief disadvantages of HASL these days, is the lack of planarity on the surface. (Note the bumps on the BGA land pattern in the image on the right.) With thru-hole or large components, an uneven surface doesn't matter so much. With the increasingly smaller BGAs and QFNs, however, surface irregularities can cause big problems.

Both Immersion silver and ENIG have nice flat surfaces. OSP (Organic Surface Preservative) has a pretty flat surface too, but it's not used much except in high volume consumer goods or specialized applications.

By Duane Benson
Oh, the pain! Save me, William.