Quick Prototyping Solutions

PCB Makers Up Their Game

Today’s embedded systems engineers have a rich variety of PCB quick prototyping resources to get their designs up and running. The PCB production and assembly vendors listed here feature lots of powerful online quoting tools, sophisticated PCB manufacturing expertise and world-class support services.

Accutrace
www.pcb4u.com
Location: Santa Clara, CA
Accutrace serves the electronics industry’s needs for quick turn PCB fabrication from prototype to production. They can manufacture only what is needed, when it’s needed—and in the amount needed. No need to worry about long shelf life or tying up your capital in bare board inventory.
Services: PCB capabilities: Capabilities: Up to 50 layers; any layer HDI; blind and buried vias; 2-mil line width and spacing; copper up to 16 oz. Materials supported: FR4, Rogers, ISOLA, Polymide-flex, Metal core, Taconic and Magtron

Advanced Circuits
www.4pcb.com
Location: Aurora, CO
3rd largest PCB manufacturer in the US. Advanced Circuits also offers exclusive services to help customers with their PCB Projects. Advanced Circuits can help you with all aspects of PCB fabrication—from manufacturing through assembly. It can create rapid prototypes and even provide weekend turns to get you your orders when you need them.
Services: Full spec PCBs, small quantity / quick turn PCBs, custom spec / quick turn PCBs, highly specialized precision PCBs and large scale production. No order is too small or too large.

AP Circuits
www.apcircuits.com
Location: Calgary, Canada
AP Circuits is a quick turn-around manufacturer of custom PCBs. Founded in 1984, AP Circuits became the world’s first facility devoted to affordable rapid printed circuit board prototyping. Over thirty years of experience getting your project done right and delivered on time.
Services: Quick turn PCB fabrication services include: Flex, semi-rigid, Multi-layer to 24 layer at 3 mil with multiple substrate options, laser drilling, blind/buried vias, Boring and countersink, direct metalization, UL/ISO/MIL/RoHS

Beta Layout
uk.beta-layout.com
Loc
ation: Shannon, Ireland
Beta Layout’s PCB-POOL operation is Europe’s largest manufacturer of PCB prototypes, with over 36,000 customers worldwide. PCB-POOL cost sharing principle enables system designers to benefit from low prices. You can calculate the prices instantly online using the PCB-POOL’s Online price calculation. PCBs using special technologies and materials can also be sourced directly from the company, from prototype to series production quantities.
Services: Prototype PCBs or small series PCBs in 1 – 6 working days; Laser-cut SMD-Stencils in 1-3 working days; Fully populated SMD and THT prototype boards in 2 working days; Support for PCBs with embedded UHF RFID modules

Beta Layout has an online pricing calculation tool that lets you unload your Eagle BRD files for 3D vacuolation.

Custom Circuit Boards
www.customcircuitboards.com
Location: Phoenix, AZ
Custom Circuit Boards is a full service quick turn PCB manufacturer located in Phoenix, Arizona with the capabilities to fabricate your prototype and production quantity PCBs. It We specializes in Quick turn PCB services with an industry leading turnaround time as fast as 24 hours. The company also does PCB prototypes, production PCBs and multilayer PCBs.
Services: From 1 to 40 PCB layers; Board material support includes: FR4, Rogers, Polyimide, Teflon, Black FR4, Arlon AR350, Getek Copper Clad Thermal Substrates, Hybrid (Rogers and FR4) BT Epoxy, Nelco 4013, Metal Core Materials

EzPCB
www.ezpcb.com
Location: Shenzhen, China
EzPCB is an online provider of PCB manufacture and PCB assembly products and services. Based in China, the company’s worldwide business has been growing rapidly since its launch in 2004. EzPCB has supplied high quality PCBs—and related products and services—for over 2,000 customers from more than 40 countries. Its customers include amateurs, small businesses, universities and many world-class companies and organizations including Jet Propulsion Laboratory, Micron, Siemens, STMicroelectronics and Rohm.
Services: PCB manufacturing, PCB assembly, cabling, enclosures, keypads, stencils and components, one-stop turnkey services and design consultation

Example of a 12-layer HDI boards with buried and blind vias built by ExPCB.

Epec
www.epectec.com
Location: New Bedford, MA
Epec specializes in custom, build to print electronics. It has a global team of engineers, designers, R & D innovators, product managers, manufacturing/supply chain professionals, quality assurance personnel and sales/customer service staff, all of whom are experts in their fields. Rather than limit its production capacity to its US and UK manufacturing centers, Epec has developed UL certified world class production facilities which are ISO-9001, QS-9002,
TS-16949, with aligned technology roadmaps and quality systems.
Services: Provides complete engineering and design services, from concept through production, in a quick and efficient time frame. Capabilities include: battery pack design and assembly, PCB electronic design, cable assembly design, flex and rigid-flex circuit design, user interface and more.

Imagineering
www.pcbnet.com
Location: Elk Grove Village, IL
Imagineering acts as a reliable source for high quality and on time PCBs. Its quick turn prototypes not just intended for testing and verification of designs. Every one of its boards meet
IPC-A-600 F (Class2) standard, be it prototype or production. Specializes in quick turn prototypes, as well as rapid turn production.
Services: PCB assembly capabilities summary: SMT, Flip chip, thru hole, Flex circuit assembly, cable assemblies, lead-free assembly and sire harness assembly. Full Turnkey service for all customers if needed as well as partial turn-key and consignment orders. PCB capabilities include: 22 layer fabrication, hole sizes down to 8 mil plated and 5 mil laser drilled, 3 mil line width and spacing, 6oz copper and a maximum PCB thickness up to .300″.

MacroFab
www.macrofab.com
Location: Houston, TX
MacroFab’s mission is to create the future of electronics manufacturing through user-centric, cloud-based technology. In October 2017 the company launched its 10-day Prototype turnaround service. This service benefit teams that quickly iterate on designs to finalize to their products.
Services: MacroFab’s software allows you to control and manage your entire PCBA manufacturing from start to finish. You can update your PCB layers and BOMs online, then approve the files for production.

MacroFab lets you upload your product design files directly onto its online platform. You can receive an instant quote and place your order without delays.

OurPCB
www.ourpcb.com
Location: Shijiazhuang Hebei, China
OurPCB is a multi-national PCB manufacturing and PCB assembly company that provides global service and support while using its own Chinese manufacturing capabilities. Company has provided professional PCB production and assembly services for more than 2,500 customers around the globe.
Services: Assembly capabilities include BGA, LGA, QFN, QFP, DIP and SIP. The smallest SMT footprint it can mount is 0201. Factory can also provide programming and wiring as well as injecting and conformal coating services.

PCBCart
www.pcbcart.com
Location: Hangzhou, China

PCBCart is a professional PCB production service provider with more than 10 years of experience in the electronics manufacturing industry. We’ve manufactured printed circuit boards for more than 10,000 companies and over 80 countries around the world. Fast, affordable prototype assembly they take your unique PCB designs, prepare them for the assembly process and perform comprehensive testing to ensure they meet your precise performance requirements. Can provide a complete turnkey PCB prototype assembly featuring a one-stop shop approach.
Services: Development, manufacturing, assembly and testing of custom PBCs; Rapid PCB prototyping; Circuit boards manufacturing: PCB assembly; Components sourcing services

PCB Unlimited
www.pcbunlimited.com
Location: Tualatin, OR
In 2003, PCB Unlimited’s sister company Stencils Unlimited pioneered the internet SMT stencil quote and order process. In 2008, PCB Unlimited took it one step further by providing a one-stop-shop where engineers can quote and order online US and offshore PCB services and everything else they need for their PCB projects.
Services: US PCB fabrication including Rigid, Flex and Rigid-Flex PCBs; Offshore PCB Fabrication; US Quick-Turn Prototype PCB Assembly and Low Volume Production followed by PCB Unlimited’s offshore operation to service your high-volume production needs

Screaming Circuits
www.screamingcircuits.com
Location: Canby, OR
Screaming Circuits, a division of Milwaukee Electronics, was founded in 2003 to reinvent electronics manufacturing. Unlike old-fashioned manufacturing models that focused on mass volumes and cost-control through rigidity, Screaming Circuits specializes in fast and flexible prototype and short-run assemblies. It offers short-run production for higher volumes without forecasts, NRE charges or volume commitments. If you need to go a step further with scheduled production, its parent company Milwaukee Electronics provides a full range of electronics manufacturing services, from original design to volume production and life-cycle management.
Services: PCB fabrication, PCB assembly, parts sourcing, layout engineering, prototype to volume production transitioning

Sierra Circuits
www.protoexpress.com
Location: Sunnyvale, CA
Sierra Circuits is an ISO 9001:2015, ISO 13485:2016 and MIL-spec MIL-PRF-55110 certified, Silicon Valley-based, high-technology PCB manufacturer and assembler. It specializes in quick turn PCBs and medium production. By owning its manufacturing and assembly facilities, the company controls every aspect of the production schedule and quality.
Services: Micro/fine line PCBs, PCB assembly, flexible PCBs, lead-free PCBs, high-reliability PCBs, no-touch PCBs, burn-in PCBs, R&D PCBs, MIL-spec PCBs, PCB design

Sierra Circuits can produce Flex PCBs with flex from 1 to 16 layers.

SlingShot Assembly
www.slingshotassembly.com
Location: Denver, CO
SlingShot Assembly’s state-of- the-art production facility handles prototype and low-volume production orders. From a single board and up, they use the latest software, processes and equipment to produce high-quality assemblies fast and at a reasonable price. Customers use the company’s assembly services for early prototype runs when they need high-quality assemblies completed in a matter of a few days. Typically, the quantities for early prototypes range from a single board to about 50. Once initial testing of early prototypes is completed, many customers move to late-stage prototyping or pre-production assemblies.
Services: Quick turn PCB assembly, standard assembly turn time: 2 – 3 days (turn times as fast as 24 hours available), prototype and low-volume production (single orders welcome, 100% turn-key components, turn-key board fabrication encouraged, test (including flying probe and functional test), conformal coating, limited box build services, web-based BOM sourcing and more.

This article appeared in the May 334 issue of Circuit Cellar

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Note: We’ve made the October 2017 issue of Circuit Cellar available as a free sample issue. In it, you’ll find a rich variety of the kinds of articles and information that exemplify a typical issue of the current magazine.

Device Silences TV Commercials

Arduino-Controlled Solution

Ever wish you could block out those annoying TV ads? Tommy describes in detail how he built a device for easily muting the audio of commercials. His project relies on three modules: a UHF radio receiver, an IR module and an Arduino Trinket board.

By Tommy Tyler

Does your blood start to boil as soon as one of those people on TV tries to sell you precious metals, a reverse mortgage, a miraculous kitchen gadget or an incredible weight reduction plan? Do you want to climb the wall the next time someone says “But wait! Order now and get a second one free . . .“? Believe it or not, there was a time long ago when TV commercials were actually entertaining. That was before commercial breaks evolved from 30 second or one-minute interruptions into strings of a half-dozen or more advertisements linked end-to-end for three to five minutes—sometimes with the exact same commercial shown twice in the same group! What is perhaps most annoying is the relentless repetition.

Historically, all the feeble attempts at TV commercial elimination have been applied to recordings on VCRs or DVRs. Anyone who watches programming that’s best enjoyed when viewed in real-time—news, weather and sports—has probably wished at one time or another for a device that can enable them to avoid commercials. They long for a device that could be inserted between their TV and the program source—whether it be cable, satellite or an OTA antenna—to instantly recognize a commercial and blank the screen, change channels or somehow make it go away. The technology for doing that does exist, but you’ll probably never find it applied to consumer products. Since funding of the entire television broadcast industry is derived from paid advertisements, any company that interferes with that would face enormous opposition and legal problems.

After many years of searching the Internet I’ve concluded it is wishful thinking to expect anyone to market a product that automatically eliminates commercials in real-time. I decided to work instead on the next-best approach I could think of: A device that makes it quick and easy to minimize the nuisance of commercials with the least amount of manual effort possible. This article describes a “Kommercial Killer (KK)” that is controlled by a small radio transmitter you carry with you so it’s easily and instantly accessible. No scrambling to find that clumsy infrared remote control and aim it at the TV when a commercial starts. Just press the personal button that’s always with you, even while remaining warm and cozy curled up under a blanket.

Kommercial Killer

The KK operates from anywhere in the home, even from another room completely out of sight of the TV and can be triggered at the slightest sound of an advertisement, political message, solicitation or perhaps even a telephone call. It works with any brand and model TV without modifications or complicated wiring connections by using the TV’s infrared remote control system. If you get a new TV, its remote control can easily teach KK a different MUTE command. Don’t worry about leaving the room with the TV muted. KK automatically restores audio after a certain amount of time. The default time is three minutes, the length of a typical commercial break, but you can easily configure this to any amount of time you prefer. And when you want to restore audio immediately—for example if you have muted non-commercial program material by mistake or if a commercial runs shorter than expected—just press your transmitter button again.

Figure 1
Schematic of the Kommercial Killer

KK is built mainly from three commercially available modules that do all the heavy lifting (Figure 1). The first module is a miniature UHF radio receiver. The second is an infrared module that can learn and mimic the TV mute signal. The third module is an Arduino Trinket board that provides commercial break timing and overall control. This article explains how to load a small program into that module without needing any special equipment or training, and even if you have absolutely no previous experience with Arduino devices.

The three modules are small and inexpensive ($7 to $10 each) and with just eight additional components KK can be built on an open perf board, strip board or enclosed in a 6-inch3 box. It is powered from the same USB Micro cable you use to load or modify the Arduino program, or from any other available USB port or 5 V charger.

UHF Receiver Module

The best UHF radio transmitters and receivers are all manufactured in China, and there are no major distributors in the U.S. So, order this item early and be prepared to wait about 20 days for delivery. After sampling many different remote controls to evaluate performance, quality, cost and shipment, I selected a product manufactured by the Shenzhen YK Remote Control Electronics Company, whose products are sold and shipped through AliExpress. Shenzhen remote controls use two types of receivers. . …

Read the full article in the May 334 issue of Circuit Cellar

After you’ve read the full article, don’t forget to go the the Article Materials Page for useful links and information.
Don’t miss out on upcoming issues of Circuit Cellar. Subscribe today!
Note: We’ve made the October 2017 issue of Circuit Cellar available as a free sample issue. In it, you’ll find a rich variety of the kinds of articles and information that exemplify a typical issue of the current magazine.

MPU-Based SOM Meets Industrial IoT Linux Needs

Microchip Technology has unveiled a new System on Module (SOM) featuring the SAMA5D2 microprocessor (MPU). The ATSAMA5D27-SOM1 contains the recently released ATSAMA5D27C-D1G-CU System in Package (SiP). The SOM simplifies IoT design by integrating the power management, non-volatile boot memory, Ethernet PHY and high-speed DDR2 memory onto a small, single-sided printed circuit board (PCB). There is a great deal of design effort and complexity associated with creating an industrial-grade MPU-based system running a Linux operating system. Even developers with expertise in the area spend a lot of time on PCB layout to guarantee signal integrity for the high-speed interfaces to DDR memory and PHY while complying with EMC standards.

The SAMA5D2 family of products provides an extremely flexible design experience no matter the level of expertise. For example, the SOM—which integrates multiple external components and eliminates key design challenges around EMI, ESD and signal integrity—can be used to expedite development time. Customers can solder the SOM to their board and take it to production, or it can be used as a reference design along with the free schematics, design and Gerber files and complete bill of materials which are available online. Customers can also transition from the SOM to the SiP or the MPU itself, depending on their design needs. All products are backed by Microchip’s customer-driven obsolescence policy which ensures availability to customers for as long as needed.

The Arm Cortex-A5-based SAMA5D2 SiP, mounted on the SOM PCB or available separately, integrates 1 Gbit of DDR2 memory, further simplifying the design by removing the high- speed memory interface constraints from the PCB. The impedance matching is done in the package, not manually during development, so the system will function properly at normal and low- speed operation. Three DDR2 memory sizes (128 Mb, 512 Mb and 1 Gb) are available for the SAMA5D2 SiP and optimized for bare metal, RTOS and Linux implementations.

Microchip customers developing Linux-based applications have access to the largest set of device drivers, middleware and application layers for the embedded market at no charge. All of Microchip’s Linux development code for the SiP and SOM are mainlined in the Linux communities. This results in solutions where customers can connect external devices, for which drivers are mainlined, to the SOM and SIP with minimal software development.

The SAMA5D2 family features the highest levels of security in the industry, including PCI compliance, providing an excellent platform for customers to create secured designs. With integrated Arm TrustZone and capabilities for tamper detection, secure data and program storage, hardware encryption engine, secure boot and more, customers can work with Microchip’s security experts to evaluate their security needs and implement the level of protection that’s right for their design. The SAMA5D2 SOM also contains Microchip’s QSPI NOR Flash memory, a Power Management Integrated Circuit (PMIC), an Ethernet PHY and serial EEPROM memory with a Media Access Control (MAC) address to expand design options.

The SOM1-EK1 development board provides a convenient evaluation platform for both the SOM and the SiP. A free Board Support Package (BSP) includes the Linux kernel and drivers for the MPU peripherals and integrated circuits on the SOM. Schematics and Gerber files for the SOM are also available.

The ATSAMA5D2 SiP is available in four variants starting with the ATSAMA5D225C-D1M- CU in a 196-lead BGA package for $8.62 each in 10,000 units. The ATSAMA5D27-SOM1 is available now for $39.00 each in 100 units The ATSAMA5D27-SOM1-EK1 development board is available for $245.00.

Microchip Technology | www.microchip.com

Reliability and Failure Prediction: A New Take

HALT methodology has been a popular way to test harsh environment reliability. A new approach involves PCB design simulation for vibration and acceleration for deeper yet faster analyses.

By Craig Armenti & Dave Wiens—Mentor Board Systems Division

Many electronic products today are required to operate under significant environmental stress for countless hours. The need to design a reliable product is not a new concept, however, the days of depending on a product’s “made in” label as an indicator of reliability are long gone. PCB designers now realize the importance of capturing the physical constraints and fatigue issues for a design prior to manufacturing to reduce board failure and improve product quality.

Simulation results should be available in a two-phase post-processor for each simulation, providing broad input on the PCB’s behavior under the defined conditions.

Simulation results should be available in a two-phase post-processor for each simulation, providing broad input on the PCB’s behavior under the defined conditions.

Although every product is expected to fail at some point. That’s inevitable. But premature failures can be mitigated through proper design when proper attention is paid to potential issues due to vibration and acceleration. ….

Read this article in the August 325 issue of Circuit Cellar

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The Perfect PCB Prototype

Interested in constructing perfect PCB prototypes? Richard Haendel has the solution for you. In this article, he explains how five simple steps—print, mount, punch, fit, and evaluate—can save you a lot of time and money.

The following article first appeared in Circuit Cellar 156.


Who designs and builds your prototype circuit boards? The other department? Oh. Well, in that case, nice seeing you. Just flip past this article and enjoy the rest of the magazine.

On the other hand, if you’re a do-it-yourself engineer like me, then perhaps my technique for prototyping prototypes will interest you (see Photo 1). It’s so easy, cheap, and obvious, I have trouble believing that no one else has done it before. If you have, please let me know. I’d love to compare notes. The entire process can be described in five words: print, mount, punch, fit, and evaluate.

Photo 1: It doesn’t get any easier than this (or cheaper). Just remember to print, mount, punch, stuff, and evaluate.

Photo 1: It doesn’t get any easier than this (or cheaper). Just remember to print, mount, punch, stuff, and evaluate.

PRINT

Your printer must be able to print a full-scale, moderately accurate representation of your PCB layout. I say “moderately accurate,” because, after all, a 10% error on a 0.4″-spaced resistor is only 0.04″. That’s close enough for most through-hole designs. Surface mounting, however, can be a problem. But because I don’t normally do surface mounting, it’s not a problem for me.

I use two printers for development: a color ink-jet and a black and white laser-jet. Both are fairly old, but they still have more than enough accuracy for this purpose. The laser-jet is probably a little better, but not by much.

Your printed layout must show (at minimum) the holes and component layout. You may or may not need to see the traces; it depends on what you’re hoping to accomplish. The traces are superfluous for test fitting (e.g., to make sure that components don’t touch each other); however, if you’re building a full-scale concept model, you’ll need as much detail as is practical. In fact, with a little more effort, you could print the top traces on one sheet and the bottom traces on another, glue them to the foam board on opposite sides (taking care to line up the holes, of course), and make yourself a full-scale PCB model. Cool.

MOUNT

Trim the excess white space from the sheet containing your printed image, because it will just get in the way. Next, cut a piece of foam board slightly larger than your layout. A utility knife and metal ruler work well for this. Peel the backing from the foam board’s adhesive side; of course, if you don’t have the self-adhesive kind, simply apply dry glue (from a glue stick) to either the board or paper. After that, carefully position one corner of your image on the foam board and smoothen it. Rub gently but firmly with a soft cloth or paper towel to permanently “seat” the image.

If you get air bubbles or wrinkles, throw it away and start over. Remember, your pattern must be accurate. You can probably make a new one faster than you can fix a damaged one. A little practice goes a long way toward achieving perfect results.

PUNCH

Using a pushpin (or a similar instrument), carefully punch your holes. As you can see in Photo 2, I use metallic pushpins with longer-than-usual shafts. Naturally, the shorter plastic pushpins will work just as well. Thumbtacks, however, are not a good choice; they’re pretty rough on the fingernails.

Photo 2: A small pin is my favorite tool for punching holes in the foam board.

Photo 2: A small pin is my favorite tool for punching holes in the foam board.

Note that this stage can be tedious, especially if you have a large board with many holes. Take your time. The holes should be centered as accurately as possible. Also, don’t push the pin all the way through; it’s merely intended to puncture the paper front so the component’s pins can penetrate the foam and have it “grab” them. In other words, you want a snug fit so the pieces don’t (easily) fall off the board.

That’s how it works for IC sockets and connectors with short leads (i.e., less than the thickness of the board). However, resistors and other parts with longer leads are a different matter. In this case, you must either trim the leads—which is fine if you’re not planning to reuse the component—or extend the hole to the backside with something like a map pin. That’s what I usually do.

FIT

That’s right. Simply fit (or stuff) your components as you would a real circuit board. Components with short leads should be easy to fit; however, those with longer leads may need persuading. Simply insert the part, grab one lead close to the board’s surface with needle-nose pliers, and gently (but firmly) coax it through the hole. Sometimes this can be a pain, especially with small-gauge component leads (e.g., ceramic capacitors). You may need to enlarge the hole from the front or backside. Remember: practice, practice, practice.

EVALUATE

In other words, use it for whatever purpose you need. Most of the time, I make these models just to test my board design and confirm that all parts will fit before committing to a manufactured prototype. After that, it’s trash. If the design is significant (pronounced “expensive to produce”), then I may make others until I’m confident of perfection.

I must confess, though, most of my models are nowhere near as neat and attractive as the one pictured in this article. Frequently, the images are slapped on a piece of scrap foam, tested, and tossed within 5 min. or less.

SO, WHAT’S IT COST?

Not much. Just the other day, I purchased a 20″ × 30″, 3/16″ thick sheet of white self-adhesive foam board at a local hobby store for $4.99. (The nonadhesive type was about $1 less.) Therefore, the cost is $4.99 divided by 600 square inches, or a mere $0.00832 per square inch—that’s less than a penny. At that rate, this board cost only $0.07.

IS IT WORTH IT?

You bet! I’ve caught numerous board design and layout errors with this technique. I’ve also learned that legends on the silk-screen layer don’t always match the physical part as closely as you may expect. This is good to know when you’re tight on board space and need to fudge a little.

Photo 3: Notice that D1 will not actually touch J2, as the PCB layout program’s silkscreen outline indicates.

Photo 3: Notice that D1 will not actually touch J2, as the PCB layout program’s silkscreen outline indicates.

I was able to crowd D1 between J2 and J3, because J2 is 0.08″ smaller than its silkscreen outline (see Photo 3). So, even though D1 appears to touch J2, there’s actually 0.04″ between them, which is more than enough for my design.

So, did I lie? Is this not as simple as can be? And cheap! Try it yourself and see.—By Richard Haendel (Circuit Cellar 156)

Full Schematic and PCB Layout in One Project File

TARGET 3001! combines the full schematic and PCB layout in one project file. Schematic and layout are always in a consistent state. An embedded PSpice simulator enables the modeling of the electrical function of the circuit eliminating errors early in the design phase.

TARGET 3001! offers more than 38,000 components in a local MySql database. When placed on a server, an entire design team can simultaneously access the same component source. If a component is placed in a design, its drawing and all its properties still can individually be changed independent of the database. Most components are furnished with a 3-D model so that a PCB can be easily inspected in a live 3-D view. A STEP file import allows for the creation of custom 3-D models; the STEP export allows the 3-D printing of an exact model of your PCB with components.

Besides XGerber and Excellon, TARGET 3001! provides a wide range of industry standard manufacturing formats. It also includes a tool for isolation milling, outputting the data in G-Code and HPGL. Open and save Eagle projects. PCB sizes up to 47″ × 47″ and an embedded front-panel designer make TARGET 3001! the perfect tool for high-end makers as well as development pros who want to move quickly from design idea to finished product.

You can try a free version for double-sided projects up to 250 pins/pads at: www.target3001.com.

Source: Ing.-Buero FRIEDRICH

21st-Century Electronics Craftsman: Meet Saar Drimer

Saar Drimer (PhD, Cambridge) runs Boldport, a London-based hardware and prototyping consultancy that specializes in circuit boards. Wisse Hettinga recently met with Drimer to discuss PCB design, electronics craftsmanship, and his various engineering projects.

Saar Drimer, electronics craftman

Saar Drimer, electronics craftman

Hettinga writes:

The Art of Electronics is a book that’s well-known by many electronic engineers all over the world. Written by Horowitz and Hill, the first edition was published in 1980 and recently, in 2015, a third edition was released. Over the past 35 years, the book has been an inspiration and resource for many engineers eager to learn about the art of designing with electronics. But there is also a real art of electronics. To discover what that is, I traveled to London to meet up with Saar Drimer. His workplace was in one of the characteristic arches underneath London Bridge Station. With the constant rumble of the trains arriving and pulling out of the station in the background, he showed me some of his work.

SOMETHING COMPLETELY DIFFERENT
Drimer’s designs are completely different from what we usually see on PCBs. Where most of our designs end up as small rectangles with only a few holes for the assembly screws, his boards take different shapes. Some are swirly, sometimes animal-like. At other times, he integrates components right into the board in special holes, as you can see in his Tiny Engineer Superhero Emergency Kit. Often there is no straight copper line to be found; they go all over the place and are a vital part of the total design.

Emergency kit

The Tiny Engineer Superhero Emergency kit

A PCB designed by Drimer asks for exposure and can be interesting for art’s sake only, but also for marketing purposes where drawing attention and presenting a surprise is required. One of his designs even features in the women’s magazine Marie Claire!

DESIGNING THE OTHER WAY AROUND
Where many of us try to put all the PCB and wiring in a (mostly) gray box and leave it out of sight, Drimer is doing exactly the opposite: he is trying to expose it. His end product is the PCB and that is where his art comes into the picture—in many exciting formats. In many ways, Saar is an engineer like many of us. He is extremely knowledgeable about electronics and designing. But when it comes to the latter, he is using unorthodox methods. Where we start with the schematics, Drimer starts with the form and shape of the final PCB—basically, he designs the other way around!

Working and designing in the opposite direction is not easy with existing PCB CAD programs like Eagle or Altium. They all start with a schematic and are using component libraries routing the final layout in the most effective or smallest footprint PCB. Their rigid, straightforward approach is excellent when designing for just another rectangle PCB. But if you want new and creative designs, you need to think of a different way of working and using other tools. If you want to change the way of thinking and designing, you need to be able to use free forms and the routing cannot be left to the CAD program. And that is exactly what Drimer is doing.

THE CRAFTSMAN’S TOOL
To be able to start with a different type of design, Drimer was left with no choice but to start developing his own PCB CAD design program. Unlike most of us who call ourselves “engineer,” Drimer calls himself ”craftsman”—and as a true craftsmen, he makes his own tools. PCBmodE is Drimer’s custom PCB CAD program. The “mod” in PCBmodE has a double meaning, Drimer explained. “The first is short for ‘modern’ in contrast to tired, old EDA tools. The second is a play on the familiar ‘modifications,’ or ‘mods,’ done to imperfect PCBs. Call it ‘PCB mode’ or ‘PCB mod E’, whichever you prefer,” he said.
PCBmodE is a PCB design Python script that creates an SVG from JSON input files. It then creates Gerber (the standard software to describe the PCB images: copper layers, soldering mask, legend, etc.) and Excellon files for manufacturing. With no graphical interface, PCBmodE enables you to place any arbitrary shape on any layer because it is natively vector-based. Most of the design is done in a text editor with viewing and some editing (routing) completed with Inkscape. (Inkscape is a professional vector graphics editor for Windows, Mac OS X, and Linux. It’s free and open source.) On his website, Drimer explains how to work with the program.

“PCBmodE was originally conceived as a tool that enables the designer to precisely define and position design elements in a text file, and not through a GUI. For practical reasons, PCBmodE does not have a GUI of its own, and uses an unmodified Inkscape for visual representation and some editing that cannot practically be done textually,” said Drimer.

A typical PCBmodE design workflow is as follows:

  • Edit JSON files with a text editor
  • “Compile” the board using PCBmodE
  • View the generated SVG in Inkscape
  • Make modifications in Inkscape
  • Extract changes using PCBmodE
  • Back to step 1 or step 2
  • Generate production files using PCBmodE

If you want to give PCBmodE a try, simply download it at www.pcbmode.com. It works with Linux, but Drimer is interested in results on other OS platforms as well. For starters, a “hello solder” design is currently available.

Hello Solder

Starter example: Hello Solder

THE CRAFTSMAN’S WORK
Examples of Drimer’s work are posted on his website, www.boldport.com. I especially like the Tiny Engineer Superhero Emergency Kit’ design where the components are integrated into the PCB itself resulting in a very flat design. You will also notice he is not using straight lines and angles for the traces. It is more of a pencil drawing; the traces flow along the lines of the PCB and components.

You might ask why on earth someone would put so much effort into all of this? Don’t ask! But, if you like, here are a few answers. First, because it is an art. Second, it is Drimer’s full-time job and he hopes to expand the business. And third, working differently from the norm tends to generate fresh ideas and exciting solutions—and that is what we need more of.

This article appears in Circuit Cellar 306 (January 2016).

Interconnect Defects (ICDs) Explained

What is an Interconnect Defect (ICD)? An ICD is a condition that can interfere with the internal circuit connections in a printed circuit board (PCB). These internal connections occur where the innerlayer circuit has a drilled hole put through it. PCB processing adds additional copper into the drilled hole to connect the innerlayer circuits together and bring the circuit to the PCB board surface where connectors or components are placed to provide final function.

If there is a defect at or near this interconnect or plating and innerlayer copper, it could lead to failure of a specific circuit (or net). This defect typically causes open circuits, but could be intermittent at high temperatures. Of significant concern is that the functionality may be fine as the PCB is built, but will fail in assembly or usage, becoming a reliability risk. This latency for the defect has put ICDs on the serious defect list in the industry. Another item is that ICDs have increased in frequency over the past five to seven years, making this a higher priority issue.

The majority of ICDs fall into two categories: debris-based ICDs and copper bond failure ICDs. Debris-based ICDs are caused by material left behind by the hole drilling process. This material is supposed to be removed from the holes, but is not when ICDs are found. Some causes are drill debris residues, drill smear and particles (glass and inorganic fillers) embedded into the innerlayer copper surface. The increases in this ICD type seems to be related to the increased usage of low Dk/low Df materials that use inorganic filler types. These materials generate more drilling debris and are often more chemically resistant materials, compared to standard FR-4 epoxy materials. This combination of effects makes the drilled holes much more difficult to clean out completely.

Debris-based ICD

Debris-based ICD

Copper bond failure ICDs occur when the copper connection is physically broken. This can be due to high stress during assembly or use, or the copper bond being weak (or a combination). This failure mode is also design related, in particular, increased PCB thickness, increased hole size and wave soldering all tend to increase the risk of copper bond ICDs. It seems that there has been an increase in the rate of this ICD type, which is related to increased lead-free soldering temperatures and increased board thickness over the past 10 years. Note: This condition also occurs on HDI microvias. The causes are similar but the processing is different.

Copper bond failure ICD

Copper bond failure ICD

Reliability testing has been run on both types of ICDs. Copper bond type ICDs are a significant reliability issue. They show up as assembly failures and product with weakness may have increased tendency for field failures. Drill debris type ICDs have not been shown to be a significant reliability issue in several studies, but they are an industry specification failure, so they affect product yield and costs. Well run IST testing, using a valid coupon structure, has been a very valuable testing method for determining risk due to ICDs.

ICDs can be prevented by good PCB design and improved PCB processing methods. Debris type ICDs are a function of drilling parameters and desmearing. Many of the newer materials with fillers do not drill like standard FR-4. Instead of forming a chip during drilling, they break apart into small particles. These particles then tend to coat the drilled hole walls. One factor associated with debris ICDs is drill bit heating. Factors that result in hotter drill bits cause more debris formation and residues.
Desmearing, which is done to remove drilling residues, often needs to be more aggressive when using these material types. This has been effective at reducing or eliminating debris ICDs.

Copper bond failures are a little more complex. In PCB processing, the key factors are cleaning the innerlayer copper surface so that a strong bond can form. In addition, the electroless copper deposit needs to be in good control, having the correct thickness and grain structure, to have the required strength. Testing and experience show a good processing focus, along with appropriate reliability testing can result in consistently robust product.

Design factors also play a big role. As noted above, board thickness and hole size are key factors. These relate to the amount of stress placed upon the interconnect during thermal exposure. Eliminating soldered through-hole connectors is one of the major ways to reduce this issue, as these often contain most of the larger holes. If you need to have thick boards, look into the z-axis CTE and Tg of your material. Lower z-axis CTE values and higher Tg values will result in reduced stress.

With PCB performance requirements constantly on the rise, ICDs will remain an issue. A better understanding of ICDs will help designers reduce the impact that they have on the performance of the board. Better PCB processing practices in drilling and desmear and selecting electroless copper will improve quality. Implementing best practices will reduce opportunities for ICDs, particularly changing connector approaches. Finally, this issue is taken seriously by the PCB suppliers, many of which are working to combat the sources behind ICD failures.

Doug Trobough is the Corporate Director of Application Engineering at Isola Corp. Doug has worked introducing new material introduction and PCB processing enhancement with Isola for five years. Prior to Isola, Doug had almost 30 years of experience building a wide variety of PCB types and interconnections systems, for Tektronix and Merix Corp., in a variety of technical positions, including CTO for Merix Corp. 

This essay appears in Circuit Cellar 300 (July 2015).

Altium Launches Open Beta Program for PCB Design Tool

Altium recenlty announced an open beta program for its community-driven PCB design tool. CircuitMaker is intended to address the unique needs of the electronics maker and hobbyist community with a free software offering. Anyone interested in participating in the open beta can register now at CircuitMaker.com.open-beta-Altium

The open beta testing program enables designers to immediately download and begin using CircuitMaker while joining a collaborative electronics design community. The open beta process will also provide feedback and input to refine CircuitMaker.

CircuitMaker will be available at no cost to anyone interested in using the software, with no limits to design capability. This PCB design tool from Altium offers a polished and streamlined design tool for the maker community with features such as:

  • Comprehensive PCB design technology — Built from the foundation of existing Altium technology, all of the typical features needed for modern PCB design are built in to CircuitMaker. This includes schematic-PCB integration, interactive routing, and output generation tools.
  • Advanced community collaboration — With CircuitMaker, designers have the opportunity to collaborate in a community-driven design environment, with unlimited access to contributed design and component data. This collaboratively design process is made possible by combining an advanced, cloud-based platform and an industry-standard user experience in a native application-based design environment.
  • Streamlined interface — CircuitMaker is a native application, and provides a streamlined interface, allowing new and casual designers to create designs quickly. This removes the traditional, time-intensive learning curve usually required for new PCB design tools.

Open beta registrations for CircuitMaker begins today, and is freely available worldwide to all interested electronics designers. Those interested can register now for the open beta at the CircuitMaker website.

Source: Altium

Workspace for Open-Source Engineering

Christopher Coballes is a Philippines-based freelance R&D engineer and Linux enthusiast with more than a decade of experience in an embedded hardware/software and a passion for an open source design.

The nearby photo shows his home workspace, which includes handy tools such as a spectrum analyzer, digital oscilloscope, and a PCB etcher.

Source: Christopher Coballes

Source: Christopher Coballes

Here are some links to Coballes’s interests and work:

  • Engineering blog
  • Hi-Techno Barrio: A group of Filipino electronics enthusiasts who “aim to uncover the complexity of a modern technology and in turn make it simple, beneficial ,low-cost and free-ware resources.”

View other electrical engineering workspaces.

Automatic 3-D Data Conversion and 3D-MID Prototyping

Beta LAYOUT recently announced it is introducing 3D-MID prototypes. Molded Interconnect Device (MID) is the production of moldings with integrated conductive structures.BetaLayoutPCB

“In mass production, these moldings are manufactured using injection molding techniques, for prototyping purposes this method is not economically feasible,” Beta LAYOUT stated in a release.

In the near future, Beta LAYOUT will offer the ability to manufacture MID components in prototype and small batch quantities, including the production of formed components by 3-D printing, metallic coating, laser patterning, selective metallization, and mounting. Start of production is planned for the second quarter of 2015. For design of 3D-MID components, developers can download the free PCB – POOL edition of layout software TARGET 3001.

With “brd – to – 3D,” Beta LAYOUT offers a comprehensive 3-D package. The complete virtual circuit board package can be created directly from an EAGLE *.brd file. Features include photo realistic images of the PCB, SMD stencil and STEP file generation. In addition, a freely rotatable 3-D view in PDF format is created, which you can view with Adobe Reader. A link to order a laser sintered 3-D model of the assembled PCB is provided and a free 3-D model is offered with PCB-POOL prototype orders and can be used effectively for collision checking.

Visit Beta LAYOUT in hall A2, booth 357 at the upcoming Electronica trade show in Munich (November 11–14, 2014) for information on 3D-MID prototypes and other products.

Source: Beta LAYOUT

Bluetooth Haptic Kit

Texas Instruments recently introduced an innovative wireless haptic development kit. The DRV2605EVM-BT haptic Bluetooth kit comprises a 32-mm square PCB containing a DRV2605 haptic driver chip that controls an eccentric rotating mass motor (ERM) and a linear resonant actuator (LRA) to produce vibrations. The DRV2605 has an integrated library with more than 100 effects licensed from Immersion Corp.

Texas Instruments DRV2605EVM-BT haptic Bluetooth kit

Texas Instruments DRV2605EVM-BT haptic Bluetooth kit

You can use a circle of LEDs to display visual alerts. The board might be useful to speed up development times when designing and testing haptic effects in applications such as: watches, fitness trackers, wearables, portable medical equipment, touch screens, displays, and other devices requiring tactile feedback.

A SimpleLink Bluetooth low-energy CC2541 wireless microcontroller communicates with a free iOS app running on an iPhone or iPad. The app allows you to play predefined library waveforms, create new waveform sequences, and assign waveform sequences to in-app notifications. The app can also be used to quickly configure the DRV2605’s internal register settings: select between an ERM or LRA actuator, set the rated and overdrive voltages, configure and run autocalibration, send direct I2C commands, as well as set up the board to respond to a GPIO trigger.

The DRV2605EVM-BT haptic Bluetooth kit costs $99.

Source: Texas Instruments

Engineering Consultant and Roboticist

Eric Forkosh starting building his first robot when he was a teenager and has been designing ever since. This NYC-based electrical engineer’s projects include everything from dancing robots to remote monitoring devices to cellular module boards to analog signals—Nan Price, Associate Editor


NAN: Tell us about your start-up company, Narobo.

forkosh

Eric Forkosh

ERIC: Narobo is essentially the company through which I do all my consulting work. I’ve built everything from dancing robots to cellular field equipment. Most recently I’ve been working with some farmers in the Midwest on remote monitoring. We monitor a lot of different things remotely, and I’ve helped develop an online portal and an app. The most interesting feature of our system is that we have a custom tablet rig that can interface directly to the electronics over just the USB connection. We use Google’s Android software development kit to pull that off.

ERIC: The DroneCell was my second official product released, the first being the Roboduino. The Roboduino was relatively simple; it was just a modified Arduino that made building robots easy. We used to sell it online at CuriousInventor.com for a little while, and there was always a trickle of sales, but it was never a huge success. I still get a kick out of seeing Roboduino in projects online, it’s always nice to see people appreciating my work.

dronecell3

The DroneCell is a cellular module board that communicates with devices with TTL UARTs.

The DroneCell is the other product of mine, and my personal favorite. It’s a cellular module board geared toward the hobbyist. A few years ago, if you wanted to add cellular functionality to your system you had to do a custom PCB for it. You had to deal with really low voltage levels, very high peak power draws, and hard-to-read pins. DroneCell solved the problem and made it very easy to interface to hobbyist systems such as the Arduino. Putting on proper power regulation was easy, but my biggest design challenge was how to handle the very low voltage levels. In the end, I put together a very clever voltage shifter that worked with 3V3 and 5 V, with some calculated diodes and resistors.

NAN: Tell us about your first project. Where were you at the time and what did you learn from the experience?

butlerrobot

Eric’s Butler robot was his first electronics project. He started building it when he was still in high school.

ERIC: The Butler robot was my first real electronics project. I started building it in ninth grade, and for a really stupid reason. I just wanted to build a personal robot, like on TV. My first version of the Butler robot was cobbled together using an old laptop, a USB-to-I/O converter called Phidgets, and old wheelchair motors I bought on eBay.

I didn’t use anything fancy for this robot, all the software was written in Visual Basic and ran on Windows XP. For motor controllers, I used some old DPDT automotive relays I had lying around. They did the job but obviously I wasn’t able to PWM them for speed control.

My second version came about two years later, and was built with the intention of winning the Instructables Robot contest. I didn’t win first place, but my tutorial “How to Build a Butler Robot” placed in the top 10 and was mentioned in The Instructables Book in print. This version was a cleaner version of everything I had done before. I built a sleek black robot body (at least it was sleek back then!) and fabricated an upside-down bowl-shaped head that housed the webcam. The electronics were basically the same. The main new features were a basic robot arm that poured you a drink (two servos and a large DC motor) and a built-in mini fridge. I also got voice command to work really well by hooking up my Visual Basic software with Dragon’s speech-to-text converter.

The Butler robot was a great project and I learned a lot about electronics and software from doing it. If I were to build a Butler robot right now, I’d do it completely differently. But I think it was an important to my engineering career and it taught me that anything is possible with some hacking and hard work.

At the same time as I was doing my Butler robot (probably around 2008), I lucked out and was hired by an entertainer in Hong Kong. He saw my Butler robot online and hired me to build him a dancing robot that was synced to music. We solved the issue of syncing to music by putting dual-tone multi-frequency (DTMF) tones on the left channel audio and music on the right channel. The right channel went to speakers and the left channel went to a decoder that translated DTMF tone sequences to robot movement. This was good because all the data and dance moves were part of the same audio file. All we had to do was prepare special audio files and the robot would work with any music player (e.g., iPod, laptop, CD, etc.). The robot is used in shows to this day, and my performer client even hired a professional cartoon voice actor to give the robot a personality.

NAN: You were an adjunct professor at the Cooper Union for the Advancement of Science and Art in New York City. What types of courses did you teach and what did you enjoy most about teaching?

ERIC: I will be entering my senior year at Cooper Union in the Fall 2014. Two years ago, I took a year off from school to pursue my work. This past year I completed my junior year. I taught a semester of “Microcontroller Projects” at Cooper Union during my year off from being a student. We built a lot of really great projects using Arduino. One final project that really impressed me was a small robot car that parallel parked itself. Another project was a family of spider robots that were remotely controlled and could shrink up into a ball.

Cooper Union is filled with really bright students and teaching exposed me to the different thought processes people have when trying to build a solution. I think teaching helped me grow as a person and helped me understand that in engineering—and possibly in life—there is no one right answer. There are different paths to the same destination. I really enjoyed teaching because it made me evaluate my understanding about electronics, software, and robotics. It forced me to make sure I really understood what was going on in intricate detail.

NAN: You have competed in robotics competitions including RoboCup in Austria. Tell us about these experiences—what types of robots did you build for the competitions?

robocup

Eric worked with his high school’s robotics team to design this robot for a RoboCup competition.

ERIC: In high school I was the robotics team captain and we built a line-following robot and a soccer robot to compete in RoboCup Junior in the US. We won first place in the RoboCup Junior Northeast Regional and were invited to compete in Austria for the International RoboCup Junior games. So we traveled as a team to Austria to compete and we got to see a lot of interesting projects and many other soccer teams compete. I remember the Iranian RoboCup Junior team had a crazy robot that competed against us; it was built out of steel and looked like a miniature tank.

My best memory from Austria was when our robot broke and I had to fix it. Our robot was omnidirectional with four omni wheels in each corner that let it drive at any angle or orientation it wanted. It could zigzag across the field without a problem. At our first match, I put the robot down on the little soccer field to compete… and it wouldn’t move. During transportation, one of the motors broke. Disappointed, we had to forfeit that match. But I didn’t give up. I removed one of the wheels and rewrote the code to operate with only three motors functional. Again we tried to compete, and again another motor appeared to be broken. I removed yet another wheel and stuck a bottle cap as a caster wheel on the back. I rewrote the code, which was running on a little Microchip Technology PIC microcontroller, and programmed the robot to operate with only two wheels working. The crippled robot put up a good fight, but unfortunately it wasn’t enough. I think we scored one goal total, and that was when the robot had just two wheels working.

After the competition, during an interview with the judges, we had a laugh comparing our disabled robot to the videos we took back home with the robot scoring goal after goal. I learned from that incident to always be prepared for the worst, do your best, and sometimes stuff just happens. I’m happy I tried and did my best to fix it, I have no regrets. I have a some of the gears from that robot at home on display as a reminder to always prepare for emergencies and to always try my best.

NAN: What was the last electronics-design related product you purchased and what type of project did you use it with?

ERIC: The last product would be an op-amp I bought, probably the 411 chip. For a current project, I had to generate a –5-to-5-V analog signal from a microcontroller. My temporary solution was to RC filter the PWM output from the op-amp and then use an amplifier with a
gain of 2 and a 2.5-V “virtual ground.” The result is that 2.5 V is the new “zero” voltage. You can achieve –5 V by giving the op-amp 0 V, a –2.5-V difference that is amplified by 2 to yield 5 V. Similarly, 5 V is a 2.5-V difference from the virtual ground, amplified by 2 it provides a 5-V output.

NAN: What do you consider to be the “next big thing” in the industry?

ERIC: I think the next big thing will be personalized health care via smartphones. There are already some insulin pumps and heart monitors that communicate with special smartphone apps via Bluetooth. I think that’s excellent. We have all this computing power in our pockets, we should put it to good use. It would be nice to see these apps educating smartphone users—the patients themselves— about their current health condition. It might inspire patients/users to live healthier lifestyles and take care of themselves. I don’t think the FDA is completely there yet, but I’m excited to see what the future will bring. Remember, the future is what you build it to be.

Experimentation and Engineering

Frederic Vecoven is software engineer living in Luxembourg who enjoys experimenting with everything from his home’s central heating controller to FPGAs. He has been designing micrcontroller-based projects for more than a dozen years and is currently working on an EPROM emulator.—Nan Price, Associate Editor

 

NAN: What is your current occupation?

FREDERIC:: I am a software principal engineer at Oracle.

NAN: Your website Vecoven.com features projects involving capacitors, microcontrollers, and EEPROM and hardware emulators. Tell us a little about the projects and your design process.

vecovenFREDERIC: At work I design firmware for high-end servers. At home I like to design my own stuff, so I have full control and can create new devices and/or enhance existing ones. I work on various projects and I don’t find enough time to document all of them on the website. For example, I designed a controller for the central heating in my house, but never documented it (it’s too “custom”). I love retrocomputing, which is how my FreHD project started. This is a hard-drive emulator for TRS-80 computers.

My design process starts from an idea (I have too many, so I must carefully select one) then a lot of thinking about the future implementation (as always, designing something is about compromises). Once I have a clear view in my mind about how things should work, I start prototyping. If possible, I use a breadboard or I create a PCB. Sometimes I do a lot of simulation before starting the prototyping, as this will save a lot of time. However, that cannot be done for all projects.

NAN: How long have you been designing microcontroller-based systems?

FREDERIC: More than 15 years.

NAN: How did you become interested in technology?

FREDERIC: When I was 13 years old I fell in love with computers when I saw a TRS-80 model in high school. I am thankful to my parents, who gave me a computer one year later.
I went to college and got a master’s degree in computer science. But I wasn’t satisfied, so I studied some more years to get another master’s degree, this time in electrical engineering. The combination of software and hardware is really powerful. A few years later, I relocated to the San Francisco Bay Area, but I am back in Europe now.

NAN: Describe the first embedded system you designed. Where were you at the time? What did you learn from the experience?

FREDERIC: My first big experience with a real embedded system was when I was working for Sun Microsystems. My group was writing the firmware for the system controllers of the SunFire 3800-6900 line. The embedded system was a small SPARC CPU running Wind River Systems’s VxWorks and the firmware was almost entirely written in Java.

NAN: What was the last electronics design-related product you purchased and how did you use it?

FREDERIC: I bought some FPGAs recently. I haven’t released any project with it yet, it is still a work in progress. My hobby time is very limited.

My idea is to use a CPU core and enhance it with new instructions to enable the generation of real-time signals. FPGAs are very powerful in that area, where a microcontroller would spend most of its time processing interrupts.

NAN: Are you currently working on or planning any projects?

Vecoven_PWM

This is Frederic’s PWM prototype for his Roland Super JX synthesizer.

FREDERIC: Yes, I have rewritten the Roland JX-10/MKS-70 firmware from scratch because I wanted to add PWM waveforms. This quickly turned into a big project. Currently, the prototype setup involves a simulator running the “assigner” code on my laptop. The laptop sends the sound board commands in System Exclusive (SysEx) Musical Instrument Digital Interface (MIDI) messages, which go to a microcontroller that extracts the payload from the SysEx. The payload is then sent to the sound board, which believes it got its instructions directly from the assigner. The sound board (which runs its own microcontroller) uses an EPROM emulator connected over USB, so I can easily modify the assigner code (running in the simulator) or the sound board code (running in the EPROM emulator) without having to program any chip. Note that I didn’t have an EPROM emulator, so I designed mine.

Vecoven_scope

This oscilloscope capture shows the generated PWM signal.

FREDERIC: The power of CPUs and GPUs are really exciting. You can pretty much do everything with software now (a 32-bit core costs less than $5).
On the other side, people don’t pay enough attention to optimization, so I am sad anytime I see poorly written code. I am also excited with all the tools and hardware available today for so little cost. That wasn’t the case in the past, so it opens door to students and hobbyists.

NAN: Last question. Let’s say you had a full year and a nice budget to work on any embedded design project you wanted. Call it your “dream project.” What would it be?

FREDERIC: I would love to do some robotic design, but I am not an expert in mechanics and I don’t have the tools (e.g., lathe, milling machine, etc.). That would fill the gap: hardware, software, and mechanics.

Build an Adequate Test Bench (EE Tip #127)

It’s in our makeup as engineers that we want to test our newly received boards as soon as possible. We just can’t wait to connect them to a power supply and then use our test bench equipment (e.g., generators, oscilloscopes, switches or LEDs, and so on) for simulation.

Circuit Cellar columnist Robert Lacoste's workspace in Chaville, France.

Circuit Cellar columnist Robert Lacoste’s clean, orderly workspace in Chaville, France.

But due to our haste, the result is usually a PCB under test lying on a crowded workbench in the middle of a mesh of test cables, alligator clamps, prototyping boards, and other probes. Experience shows that the probability of a short circuit or mismatched connection is high during this phase of engineering excitement.

Test Board

Rather than requiring a mesh of test wires, it is often wise to develop a small test PCB that will drastically simplify the test phase. Here the ancillary board provided a clean way to connect a Microchip Technology ICD3 debugger, a JTAG emulator, a debug analyzer, and a power supply input.

Take your time: prepare a real test bench to which you can connect your board. It could be as simple as a clean desk with properly labeled wires, but you might also need to anticipate the design of a test PCB in order to simplify the cabling.—Robert Lacoste, “Mixed-Signal Designs,” CC25:25th Anniversary Issue, 2013.