July Circuit Cellar: Sneak Preview

The July issue of Circuit Cellar magazine is out next week! This 84-page publication will make a satisfying thud sound when it lands on your desk and it’s crammed full of excellent embedded electronics articles prepared for you.

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Here’s a sneak preview of July 2019 Circuit Cellar:

CONNECTED SYSTEMS IN ACTION

Embedded Computing
in Railway Systems
Railway systems keep getting more advanced. On both the control side and passenger entertainment side, embedded computers and power supplies play critical roles. Railway systems need sophisticated networking, data collection and real-time control, all while meeting safety standards. Circuit Cellar Chief Editor Jeff Child looks at the latest technology trends and products relevant to railway applications.

Product Focus:
IoT Interface Modules
The fast growing IoT phenomenon is driving demand for highly integrated modules designed for the IoT edge. Feeding those needs, a new crop of IoT modules have emerged that offer pre-certified solutions that are ready to use. This Product Focus section updates readers on this technology trend and provides a product album of representative IoT modules.

TECHNOLOGIES AND TECHNIQUES FOR ENGINEERS

FPGA Signal Processing
Offering the dual benefits of powerful signal processing and system-level integration, FPGAs have become a key technology for embedded system developers. Makers of chip and board-level FPGA products are providing complete solutions to enable developers to meet their application needs. Circuit Cellar Chief Editor Jeff Child explores the latest technology trends and product developments in FPGA signal processing.

Macros for AVR Assembler Programming
The AVR microcontroller instruction set provides a simplicity that makes it good for learning the root principles of machine programming. There’s also a rich set of macros available for the AVR that ease assembler-level programming. In this article, Wolfgang Matthes steps you through these principles, with the goal of helping programmers “think low-level, write high-level” when they approach embedded systems software development.

Inrush Current Limiters in Action
At the moment a high-power system is switched on, high loads can result in serious damage—even when the extra load is only for short time. Inrush current limiters (ICLs) can help prevent these issues. In this article, TDK Electronics’ Matt Reynolds examines ICLs based on NTC and PTC thermistors, discussing the underlying technology and the device options.

A Look at Cores with TrustZone-M
It’s not so easy to keep up with all the new security features on the latest and greatest embedded processors—especially while you’re busy focusing on the more fundamental and unique aspects of your design. In this article, Colin O’Flynn helps out by examining the new processor cores using TrustZone-M, a feature that helps you secure even low-cost and lower power system designs.

PROJECTS THAT REUSE & RECYCLE

Energy Monitoring Part 2
In Part 1 of this article series, George Novacek began describing an MCU-based system he built to monitor his household energy. Here, he continues that discussion, this time focusing on the electrical power tracking module. As the story shows, he stuck to a design challenge of building the system with as many components he already had in his component bins.

Variable Frequency Drive Part 1
Modern appliances claim to be more efficient, but they’re certainly not designed to last as long as older models. In this project article, Brian Millier describes how he reused subsystems from a defunct modern washing machine to power his bandsaw. The effort provides valuable insights on how to make use of the complete 3-phase Variable Frequency Drive (VFD) borrowed from the washing machine.

FUN PROJECT ARTICLES WITH ALL THE DETAILS

Windless Wind Chimes (Part 2)
In part 1 of this article series, Jeff Bachiochi built a system to simulate breezes randomly playing the sounds of suspended wind chimes. In part 2 the effort evolves into a less random, more orchestrated project. Jeff decided this time to craft a string of chromatically tuned chimes, similar to what an orchestra might use so the project could be used to play music. The project relies on MIDI, an industry standard music technology protocol designed to create and share music and artistic works.

Building a Smart Frying Pan
There’s almost no limit to what an MCU can be used for—-including objects that previously had no electronics at all. In this article, learn how Cornell University graduate Joseph Dwyer build a Microchip PIC32 MCU-based system that wirelessly measures and controls the temperature of a pan on a stove. The system improves both the safety and reliability of cooking on the stove, and has potentially interesting commercial applications.

EOG-Controlled Video Game
There’s much be to learned about how electronics can interact with biological signals—not only to record, but also to see how they can be used as inputs for control applications. With ongoing research in fields such as virtual reality and prosthetics, new systems are being developed to interpret different types of signals for practical applications. Learn how Cornell graduates  Eric Cole, Evan Mok and Alex Huang use electrooculography (EOG) to control a simple video game by measuring eye movement.

June Circuit Cellar: Sneak Preview

The June issue of Circuit Cellar magazine is out next week!. We’ve been tending our technology crops to bring you a rich harvest of in-depth embedded electronics articles. We’ll have this 84-page magazine brought to your table very soon..

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Here’s a sneak preview of June 2019 Circuit Cellar:

TOOLS AND CONCEPTS FOR ENGINEERS

Integrated PCB Design Tools
After decades of evolving their PCB design tool software packages, the leading tool vendors have the basics of PCB design nailed down. In recent years, these companies have continued to come up with new enhancements to their tool suites, addressing a myriad of issues related to not just the PCB design itself, but the whole process surrounding it. Circuit Cellar Chief Editor Jeff Child looks at the latest integrated PCB design tool solutions.

dB for Dummies: Decibels Demystified
Understanding decibels—or dB for short—may seem intimidating. Frequent readers of this column know that Robert uses dB terms quite often—particularly when talking about wireless systems or filters. In this article, Robert Lacoste discusses the math underlying decibels using basic concepts. The article also covers how they are used to express values in electronics and even includes a quiz to help you hone your decibel expertise.

Understanding PID
As a means for implementing feedback control systems, PID is an important concept in electronics engineering. In this article, Stuart Ball explains how PID can be applied and explains the concept by focusing on a simple circuit design.

DESIGNING CONNECTED SYSTEMS

Sensor Connectivity Trends
While sensors have always played a key role in embedded systems, the exploding Internet of Things (IoT) phenomenon has pushed sensor technology to the forefront. Any IoT implementation depends on an array of sensors that relay input back to the cloud. Circuit Cellar Chief Editor Jeff Child dives into the latest technology trends and product developments in sensors with an emphasis on their connectivity aspects.

Bluetooth Mesh (Part 3)
In this next part of his article series on Bluetooth mesh, Bob Japenga looks at how to create secure provisioning for a Bluetooth Mesh network without requiring user intervention. He takes a special look at an attack which Bluetooth’s asymmetric key encryption is vulnerable to called Man-in-the-Middle.

PONDERING POWER AND ENERGY

Product Focus: AC-DC Converters
To their peril, embedded system developers often treat their choice of power supply as an afterthought. But choosing the right AC-DC converter is critical to the ensuring your system delivers power efficiently to all parts of your system. This Product Focus section updates readers on these trends and provides a product album of representative AC-DC converter products.

Energy Monitoring (Part 1)
The efficient use of energy is a topic moving ever more front and center these days as climate change and energy costs begin to affect our daily lives. Curious to discover how efficient his own energy consumption was, George Novacek built an MCU-based system to monitor his household energy. And, in order to make sure this new device wasn’t adding more energy use, he chose to make the energy monitoring system solar-powered.

Building a PoE Power Subsystem
Power-over-Ethernet (PoE) allows a single cable to provide both data interconnection and power to devices. In this article, Maxim Integrated’s  and Maxim Integrated’s Thong Huynh and Suhei Dhanani explore the key issues involved in implementing rugged PoE systems. Topics covered include standards compliance, interface controller selection, DC-DC converter choices and more.

Taming Your Wind Turbine
While you can buy off-the-shelf wind power generators these days, they tend to get bad reviews from users. The problem is that harnessing wind energy takes some “taming” of the downstream electronics. In this article, Alexander Pozhitkov discusses his characterization project for a small wind turbine. This provides a guide for designing your own wind energy harvesting system.

MORE PROJECT ARTICLES WITH ALL THE DETAILS

Windless Wind Chimes (Part 1)
Wind chimes make a pleasant sound during the warm months when windows are open. But wouldn’t it be nice to simulate those sounds during the winter months when your windows are shut? In part 1 of this project article, Jeff Bachiochi builds a device that simulates a breeze randomly playing suspended wind chimes. Limited to the standard 5-note pentatonic chimes, this device is based on a Microchip PIC18 low power microcontroller.

GPS Guides Robotic Car
In this project article, Raul Alvarez-Torrico builds a robotic car that navigates to a series of GPS waypoints. Using the Arduino UNO for a controller, the design is aimed at robotics beginners that want to step things up a notch. In the article, Raul discusses the math, programing and electronics hardware choices that went into this project design.

Haptic Feedback Electronic Travel Aid
Time-of-flight sensors have become small and affordable in the last couple years. In this article, learn how Cornell graduates Aaheli Chattopadhyay, Naomi Hess and Jun Ko detail creating a travel aid for the visually impaired with a few time-of-flight sensors, coin vibration motors, an Arduino Pro Mini, a Microchip PIC32 MCU, a flashlight and a sock.

March Circuit Cellar: Sneak Preview

The March issue of Circuit Cellar magazine is out next week!. We’ve rounded up an outstanding selection of in-depth embedded electronics articles just for you, and rustled them all into our 84-page magazine.

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Here’s a sneak preview of March 2019 Circuit Cellar:

POWER MAKES IT POSSIBLE

Power Issues for Wearables
Wearable devices put extreme demands on the embedded electronics that make them work—and power is front and center among those demands. Devices spanning across the consumer, fitness and medical markets all need an advanced power source and power management technologies to perform as expected. Circuit Cellar Chief Editor Jeff Child examines how today’s microcontroller and power electronics are enabling today’s wearable products.

Power Supplies for Medical Systems
Over the past year, there’s been an increasing trend toward new products that have some sort of application or industry focus. That means supplies that include either certifications, special performance specs or tailored packaging intended for a specific application area such as medical. This Product Focus section updates readers on these technology trends and provides a product gallery of representative medical-focused power supplies.

DESIGN RESOURCES, ISSUES AND CHALLENGES

Flex PCB Design Services
While not exactly a brand-new technology, flexible printed circuit boards are a critical part of many of today’s challenging embedded system applications from wearable devices to mobile healthcare electronics. Circuit Cellar’s Editor-in-Chief, Jeff Child, explores the Flex PCB design capabilities available today and whose providing them.

Design Flow Ensures Automotive Safety
Fault analysis has been around for years, and many methods have been created to optimize evaluation of hundreds of concurrent faults in specialized simulators. However, there are many challenges in running a fault campaign. Mentor’s Doug Smith presents an improved formal verification flow that reduces the number of faults while simultaneously providing much higher quality of results.

Cooling Electronic Systems
Any good embedded system engineer knows that heat is the enemy of reliability. As new systems cram more functionality at higher speeds into ever smaller packages, it’s no wonder an increasing amount of engineering mindshare is focusing on cooling electronic systems. In this article, George Novacek reviews some of the essential math and science around cooling and looks are several cooling technologies—from cold pates to heat pipes.

MICROCONTROLLER PROJECTS WITH ALL THE DETAILS

MCU-Based Solution Links USB to Legacy PC I/O
In PCs, serial interfaces have now been just about completely replaced by USB. But many of those interfaces are still used in control and monitoring embedded systems. In this project article, Hossam Abdelbaki describes his ATSTAMP design. ATSTAMP is an MCS-51 (8051) compatible microcontroller chip that can be connected to the USB port of any PC via any USB-to-serial bridge currently available in the market.

Pet Collar Uses GPS and Wi-Fi
The PIC32 has proven effective for a myriad of applications, so why not a dog collar? Learn how Cornell graduates Vidya Ramesh and Vaidehi Garg built a GPS-enabled pet collar prototype. The article discusses the hardware peripherals used in the project, the setup, and the software. It also describes the motivation behind the project, and possibilities to expand the project in the future.

Guitar Video Game Uses PIC32
While music-playing video games are fun, their user interfaces tend leave a lot to be desired. Learn how Cornell students Jake Podell and Jonah Wexler designed and built a musical video game that’s interfaced with using a custom-built wireless guitar controller. The game is run on a Microchip PIC32 MCU and uses a TFT LCD display to show notes that move across the screen towards a strum region.

… AND MORE FROM OUR EXPERT COLUMNISTS

Non-Evasive Current Sensor
Gone are the days when you could do most of your own maintenance on your car’s engine. Today they’re sophisticated electronic systems. But there are some things you can do with the right tools. In his article, By Jeff Bachiochi talks about how using the timing light on his car engine introduced him to non-contact sensor technology. He talks about the types of probes available and how to use them to read the magnitude of alternating current (AC

Impedance Spectroscopy using the AD5933
Impedance spectroscopy is the measurement of a device’s impedance (or resistance) over a range of frequencies. Brian Millier has designed many voltammographs and conductivity meters over the years. But he recently came across the Analog Devices AD5933 chip made by which performs most all the functions needed to do impedance spectroscopy. In this article, explores the technology, circuit design and software that serve these efforts.

Side-Channel Power Analysis
Side-channel power analysis is a method of breaking security on embedded systems, and something Colin O’Flynn has covered extensively in his column. This time Colin shows how you can prove some of the fundamental assumptions that underpin side-channel power analysis. He uses the open-source ChipWhisperer project with Jupyter notebooks for easy interactive evaluation.

Power Supplies Lean Toward an Application Focus

Medical and More

Your choice of power supply can have a major impact on your embedded system’s capabilities. Power supply innovators are smoothing the way with devices designed to match application needs.

By Jeff Child, Editor-in-Chief

Arguably the unsung heroes of any embedded system design, power supplies and converters are critical enablers for meeting today’s needs. As embedded systems pack ever more intelligence into smaller spaces, power has direct implications on the size, cooling and mobility of any system.

To keep pace, power supply vendors continue to roll out more efficient products, new partitioning strategies and more compact solutions. In tandem to those trends, there’s a growing demand to reduce size, weight and power of system electronics. Driving those demands is a desire to fit more functionality in the same space or into a smaller footprint.

If you look at the power supply products released over the last 12 months, there’s been a definite uptick in new products that have some sort of application or industry focus. While this hasn’t diminished the role of general purpose power supplies, the trend has been toward supplies that include either certifications, special performance specs or tailored packaging intended for a specific application area such as medical, industrial, railway or the IoT.

Power Supplies for Medical

An example along those lines in the medical space is the TDK-Lambda brand CUS150M series of AC-DC 150 W rated power supplies announced early this year by TDK (Figure 1). The device has the capability of operating in ambient temperatures of up to 85°C without the need for forced air cooling. Certified to medical and ITE standards for Class I and II (no earth ground connection) operation, the product meets both curve B radiated and conducted emissions. CUS150M target applications include medical, home healthcare, dental, test and measurement, broadcast and industrial equipment.

Figure 1
The CUS150M series of AC-DC 150 W rated power supplies are certified to medical and ITE standards for Class I and II operation. It meets both curve B radiated and conducted emissions.

Output voltage options include 12 V, 15 V, 18 V,  24 V, 28 V and 36 V models. The CUS150M operates from an 85 VAC to 264 VAC input and has operating efficiencies up to 91%. Off-load power consumption is less than 0.5 W and a 10 V to 12 V, 0.5 A fan supply is fitted as standard.

The open frame version is in the industry standard 50.8 mm x 101.6 mm (2″ x 4″) footprint with a height of 31.5 mm. Convection cooled it can deliver 120 W at 40°C, or with forced air cooling 150 W at 50°C, 140 W at 70°C and 75 W at 85°C. With the U-channel construction variant, measuring 64 mm x 116 mm x 38.5 mm, the CUS150M can be conduction cooled via a cold plate to deliver 150 W at 50°C, 100 W at 70°C and
50 W at 80°C. Cover or top fan options are also available.

Input to output isolation is 4 kVAC (2xMoPP (Means of Patient Protection)), input to ground 1.5 kVAC (1xMoPP) and output to ground 1.5 kVAC (1xMoPP) making the series suitable for B and BF rated medical equipment. Touch current is a maximum of 100 µA, with leakage current less than 250 µA. 5,000 m is the maximum operating, transportation and storage altitude.

Encapsulated Converters

Also targeting medical applications, Minmax Technology offers its Minmax MAU01M / MSCU01M series, a range of high performance 1 W medical safety approved DC-DC converters with encapsulated SIP-7 and SMD packages. They are specifically designed for medical applications. The series includes models available for input voltages of 4.5 VDC to 5.5 VDC, 10.8 VDC to 13.2 VDC, and 21.6 to
26.4 VDC. The I/O isolation is specified for 4,000 VAC with reinforced insulation and rated for a 300 VRMS working voltage.

Additional features include short circuit protection, a low leakage current of 2 μA max. and operating ambient temperature range of -40°C to 95°C. This is achieved without de-rating and with a high efficiency of up to 84%. The MAU01M / MSCU01M series conforms to the 4th edition medical EMC standard. It meets 2xMoPP per 3rd edition of IEC/EN 60601-1 and ANSI/AAMI ES60601-1. The MAU01M / MSCU01M series offers an economical solution for demanding medical instrument applications that require a certified supplementary and reinforced insulation system to comply with latest medical
safety approvals under the 2xMoPP requirements.

Meanwhile, CUI’s Power Group added five open frame series products, ranging from
180 W up to 550 W, to its line of internal AC-DC medical power supplies (Figure 2). Certified to the medical 60601-1 edition 3.1 safety standards for 2xMoPP applications and 4th edition EMC requirements, the VMS-180, VMS-225, VMS-275, VMS-350 and VMS-550 series feature high efficiency up to 94% and high-power densities up to 30 W/in3. The devices are housed in 2″ x 4″ (50 mm x 101 mm) and 3″ x 5″ (76 mm x 127 mm) packages with profiles measuring as low as 0.75″ (19 mm), providing a compact, high density solution fokproviding a compact, high density solution for medical diagnostic equipment, medical monitoring devices and dental applications.

Figure 2
The VMS-180, VMS-225, VMS-275, VMS-350 and VMS-550 series power supplies are certified to the medical 60601-1 edition 3.1 safety standards for 2xMoPP applications and 4th edition EMC requirements.

All of these VMS series supplies provide output voltage options from 12 VDC to 58 VDC, feature wide universal input voltage ranges from 80 VAC to 264 VAC and offer no-load power consumption as low as 0.5 W. The 180 W to 550 W models also carry an input to output isolation of 4,200 VAC with leakage current ratings as low as 0.3 mA at 230 VAC. Operating temperatures range at full load from -40°C up to +50°C with forced air cooling, derating to 50% load at +70°C.

Other features include protections for over voltage, over current and short circuit, along with power factor correction and a 12 VDC / 500 mA fan output. These medical power supplies further meet EN 55011 Class B limits for conducted and radiated emissions and achieve an MTBF of 3.37 million hours, calculated per Telcordia SR-332 Issue 3. …

Read the full article in the September 338 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.