Do You Need that Part, or is It Just Habit?

At the moment, I’m working on an Arduino compatible clock. Like most of my Arduino compatible boards, this one uses an Atmega32U4, with USB built in. With the Atmega32U4, I sacrifice a little in program memory and SRAM, but gain a bit in reduced parts count.

A USB capable Arduino-compatible is, of course, programmed via USB, and can be powered by the USB port. Most Arduino boards also have a 5V regulator to be used when being powered by a wall-bug power supply. Naturally, I put the USB connector on the clock board, as well as the 5V regulator. With the two different supplies, I also put in circuitry to auto switch sources and protect the USB host when both supplies are connected at the same time.

My first PCB revision required6a00d8341c008a53ef01b8d0aae30b970c-800wi a few hand-mods, but not many. Still, I decided to respin the board and remove the two mod wires. While doing so, it suddenly occurred to me — a blinding flash of the obvious — that most cellphones and other small devices are charged with a USB-connector 5V wall-bug power supply. Why then, would I also need a separate power supply and on-board 5V regulator?

By pulling the regulator off of the board, I could eliminate a few capacitors and the supply auto-select / protection circuitry. Not only did I save in component cost, but I was able to reduce the PCB size, and thus cost, by about a third.

  1. I had the 5V regulator in the design because Arduinos can be powered by either USB or a non-regulated power supply.
  2. The reverse power protection is necessary to prevent damage to the USB host if the other power is also connected.
  3. The auto-power switching circuit is necessary so that a user doesn’t need to flip a switch or change a jumper when changing power sources.
  4. I had two extra LEDs to indicate which supply was powering the clock.

I questioned my original assumptions, found a “because it’s always done that way” and eliminated it. Assumptions are meant to be challenged.

Duane Benson
Question authority!
And then get squashed
(or, squash extra space out of your PCB)

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Higher (Cost) Education

Rensselaer Polytechnic is an outstanding academic institution, one that has minted more than a few of the stellar engineers working in the electronics industry today.

And you can count me among those who believe that if we want to ensure that top minds continue to consider careers in academia, the pay scale needs to reflect such emphasis.

But the news that Rensselaer’s president received more than $7.1 million in total pay in 2012, according to The Chronicle of Higher Education’s annual pay survey leaves me stunned.

While it’s true Rensselaer president Shirley Ann Jackson has a stellar resume and much of her pay came via a $5.9 million retention incentive that kept her in place for 10 years, the incentive bonus coupled with her annual salary of $945,000 means the real cost came to  $1.5 million a year.

Rensselaer’s annual tuition cost: $46,700 per semester (not including room and board).

How many students do we discourage from or otherwise price out of the leading colleges each year? How many of those who do suck up and write the checks leave so encumbered by student loans that they end up on Wall Street or sales or some other non-engineering area where they can recoup their “investment?” And for good measure, let’s ask what is the mission of the university in the first place?

 

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Chips Making Faces

http://blog.screamingcircuits.com/

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IPC Apex Expo Programs Highlight Technology and Innovation

Ed.: This is a guest blog from IPC.

No matter where you are in the global electronics supply chain, you’ve probably heard the phrase, “I need it now.” In this fast-moving, ever-evolving industry, we hear that a lot.

What drives what happens now? A critical combination of the latest technology and knowledge, which is what you’ll find at IPC Apex Expo 2015.

Starting with the opening keynote with Robbie Bach, former president of entertainment and devices at Microsoft and Xbox visionary, you’ll learn about the triumph of a strategic process that brought together a disparate group of talented individuals who applied entrepreneurship to build a successful consumer business within the larger Microsoft structure.

On the show floor, you’ll see and compare equipment from more than 440 of industry’s top suppliers, discover new processes to gain greater efficiency and uncover news solutions that will help improve your bottom line.

In keeping with the event’s theme, “Upgrade Your Tech-NOW-ledgy” the technical conference will feature approximately 100 technical papers detailing original research and innovations from industry experts around the world.

For best practices in design, lead-free technologies, materials, process improvement, solder joint reliability, PCB fabrication and materials, quality and reliability, the more than 30 professional development courses will go beyond theory to provide practical solutions you can implement now.

With so many outstanding courses and technical papers to choose from, and the world’s elite subject matter experts to interact with, your best registration option is the All-Access Package. This package will save you a significant amount off a la carte options, but more importantly provide the maximum learning experience for your investment.

The All-Access Package includes the technical conference, conference proceedings, standards development committee meetings, a choice of up to five half-days of professional development courses, event essentials, luncheons, design forum, and if you’re a senior-level executive – PCB supply chain leadership or EMS management council meetings.

If you want to upgrade your tech-NOW-ledgy, IPC Apex Expo 2015 is the place to be. For more information or to register, visit www.ipcapexexpo.org.

 

 

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New Motivation?

On the eve of the industry’s largest PWB show, I have begun to reflect on what the American expats whom I will meet here are doing for their Greater China employers. I wonder what they could not have done in the United States, and the reasons why. Now the game has changed. Labor costs are up. Automation is advancing. Business continues to consolidate rapidly as “blue chips” have vanished. Others are in jeopardy. Those remaining are few and far between.

One thing is certain. The days when Asian companies would buy old, tired American facilities and fix them up as a potential method of market entry are long gone. They have learned that it is better to invest in the newest technologies at the outset and not waste their funds patching and fixing near-obsolete operations. This could be one of the motivations for some American corporations to design and install new state-of-the-art automated and “green” captive PWB operations. One such venture is even predicting a bare board cost reduction of greater than 30% over his currently outsourced panels.

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The December Issue of PCD&F/CA

Our December issue hits the digital streets today and features a cover story from Terry Munson at Foresite, who performed a comparison of analytical techniques using 25 conformal-coated no-clean assemblies after environmental testing for 40°C/90%RH for 168 hr. Terry found FTIR, SEM/EDS and ion chromatography need an assist when determining the true source of contamination.

Another major feature reviews system design methodology for complex PCB designs.

Other highlights include discussion of pad-to-via clearance’s effects on solder joint strength, minimizing bottom termination component voiding, printer tooling, controlling solder paste slump and how to deal with an unhappy OEM.

As always in December, we look back at our industry friends and colleagues who passed away this year.

Finally, is free CAD a good thing? That’s the question I ask in my editorial this month.

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Actual and Potential Use of Drones in Precision Agriculture

Ed.: This is a guest blog by Alex Danovich of San Francisco Circuits.

Unmanned Aerial Vehicles (UAV), Unmanned Aerial Systems (UAS), Remotely Piloted Aircraft (RPA) or more commonly referred by mass media as drones are gaining popularity and often discussed for many new approaches to old applications. In the last couple years drones are rapidly gaining attention not only due to the traditional military applications but also civilian uses. This transition brings the drone industry closer into new commercial applications that literally pop up every day.

There are many directions of potential use but according to this economic report provided by the Association for Unmanned Vehicle Systems International (AUVSI) in 2013 more than 80% of civilian drone applications will be connected with precision agriculture (PA), creating many new jobs and billions in market value.

San Francisco Circuits took a look at the growing precision agriculture industry with a supplier and expert in this field, Michal Ruš of e-Dron. “We believe that a low-cost drone can be effective tool for precision agriculture. Our Skyhunter fixed wing configuration (under 2000 EUR) is able to map an area of 150 hectares in less than 30 minutes.”

A few hours after the drone’s flight and scan, an accurate orthophoto map and 3D surface model with RGB and NDVI imagery is created. Such models/images can be exported directly into farm management programs and variable rate prescription maps.

By providing a service-based operation instead of drone ownership, e-DRON believes it is able to remove the burden of operation, maintenance and certification of such drones by farmers. Farmers rely on timely and accurate data to make better decisions. They are focused on their crops and if drones are not bulletproof or easy to maneuver for anyone without proper training, it makes sense to leave its operation to service providers.

Skyhunter fixed wing with RGB and NIR camera dual configuration

Skyhunter fixed wing with RGB and NIR camera dual configuration

e-DRON is currently building such a bulletproof drone with the help of some consultation on custom PCB fabrication and PCB assembly from San Francisco Circuits.

Drone hardware and software. But what is the drone made of? The difference between a drone and a model aircraft/copter is the flight controller with autonomous features. In this case, the heart of the Skyhunter model consists of a Pixhawk autopilot developed jointly by the PX4 open hardware project and 3D Robotics.

The autopilot contains a six-layer PCB with isolated power nets for the main and safety processor. It’s a 1.6mm FR-4 board with 0402 standard components, minimum pitch of 0.2mm and 0.15mm spacing. Copper thickness and stackup are standard with 0.35um copper. The challenge in autopilot electronics is not the base technology, but to ensure highest quality throughout the complete production process from PCB manufacturing to assembly.

Pixhawk - advanced 32bit autopilot by 3D Robotics

Pixhawk – advanced 32bit autopilot by 3D Robotics

The payload itself consists of 2 consumer grade point-and-shoot cameras; one is the original RGB camera and the second is converted to NIR (near infrared).

The processing chain to obtain orthophoto/3D imaging of a desired piece of land has a pretty simple workflow. The mission starts with a drawing a polygon around the desired area in Mission Planner software. Once the mission is complete, the images are transferred to a powerful PC to process the remaining steps.

Depending on customer requirements, ground control points (GCPs) are measured with RTK GNSS (2cm accuracy) before the mission start. These points are then manually assigned together with images from the cameras on the software to produce an accurate geo-referenced orthophoto and 3D model. The NIR-produced orthophoto is then the most useful product for the farmers to spot the crop health immediately. Although more advanced sensors exist that would outrun the performance and accuracy of such a converted NIR camera, this is the lowest cost solution.

Applications in precision agriculture. Drone use in PA is all about saving inputs to farmers. Whether it’s an indication to use fewer pesticides, fertilizers or water for irrigation, PA will make billions of cost savings and greener food products.

The drones are good at monitoring crops for a very low relative price. When compared with satellites or manned planes/helicopters, low cost drones are cheaper and can be deployed every day, even in a cloudy day. The farmers have no other cost effective way to scout their large fields than by drones. Other than the RS detection of the crop health, drones are already able to effectively manage fields by crop dusting with variable rate technology.

Future of drones in PA. Multi-sensor drones with more advanced micro-sensors (like hyperspectral, thermal, LiDAR, etc.) and smart zonal auto-classification analytics are in development.

Swarm operations (multiple drones) with continuous remote sensing (day passive sensors and night active sensors) for larger fields and applications are all viable for scaling.

Powering the drones using solar energy with hydrogen fuel cell technology (unlimited endurance, 24/7 operation), making instant real-time cloud processing of acquired data streamed via high-bandwidth telemetry (no need for many SSD/HDDs onboard of multi-sensor drones) is also a very real application. Drones may eventually be programmed to automatically take actions of the whole lifecycle – from RS detection to immediate application of inputs. Harvest or seeding may be the next drone activity.

The future is in the sky!

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Peter Biocca, RIP

Peter Biocca, the longtime face of Kester Solder in the southern US and Mexico, passed away Monday from cancer.

I knew Peter for more than 15 years, dating back to his time with Multicore, when he was one of the regulars at the J-STD-004 and J-STD-005 meetings. Besides contributing to the standards, Peter could always be counted on to prepare papers at all the various technical conferences, participate in road shows, and fill whatever role was needed whenever anyone asked. More than that, he was simply a super nice guy, with nothing but good things to say about other people.

I knew Peter was really ill when he starting missing conferences over the past year. I filled in for him with his old friend Ray Chartrand on a session on alloy selection at SMTAI in 2013.  It didn’t occur to me at the time that I wouldn’t see him again. Knowing that now makes me very sad.

Condolences may be sent to Peter’s wife, Sandy, at:

Sandy Biocca
203 Fairfax Drive
Allen, TX 76013

RIP, Peter.

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Freescale KL03 and PCB123 at 0.4mm Pitch

Small component packages seem to be a recurring theme with me. It’s understandable, I guess. Super tiny packages are becoming more and more common and we build a lot of product with them.

The smallest we’ve built is 0.3mm pitch. Those aren’t common enough to be considered standard — they’re still an experimental assembly — but not many chips use them yet. 0.4mm, on the other hand, is something we see on a pretty regular basis.

What’s so tough about that? The biggest challenge with these form-factors seems to be footprint design and escape routing. I can see why. There really isn’t room to follow any of the standard BGA practices. You can’t fit escape vias between the pads and you can’t put vias in the pads, unless they are filled and plated over at the board house. Filled and plated vias are the easiest way to go, but it can make for an expensive board fab.

KL03 WLCSP20 on a US Lincoln penny. One of my side projects involves trying to make the smallest possible motor driver. For this project, I’ve chosen the Allegro A3903 driver. It’s a 3 x 3mm DFN (dual flatpack no leads) with 0.5mm pitch pads and a thermal pad in the middle. The microcontroller will be the new Freescale KL03 32-bit ARM in a 1.6 x 2.0mm WLCSP (wafer level chip scale) package. It also comes in a 3 x 3 x 0.5mm pitch 16 pin QFN. Without an expensive PCB, that may be my only option.

Pick your CAD package. I’m using the newest version (5.1) of Sunstone Circuit’s CAD package, PCB123, but the principles here will apply to any CAD software. If you don’t already have a copy, download PCB123 V5.1 here.

If you’ve got fast Internet, you’re done now, so go ahead and install it. You’ll need the manual too, which you can get here.

I need to eat now, so stay tuned for Part 2.

Duane Benson
Nerfvana – It’s like Nerdvana, but with more foam darts.

http://blog.screamingcircuits.com/

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Wilk the Winner

Congratulations to Edward Wilk of Facts Engineering, who won the incentive prize for filling out a recent survey of PCB West 2014 technical conference attendees.

Edward, a $50 AMEX gift card is headed your way. Thanks for your support, and thanks to everyone who took the time to respond!

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