Using Small PCs in New Ways

Innovative Interfacing

Even simple MCU-based projects often require some sort of front panel interface. Traditionally such systems had to rely on LEDs and switches for such simple interfaces. These days however, you can buy small, inexpensive computing devices such as mini PCs and tablet computers and adapt them to fill those interfacing roles. In this article, Wolfgang steps you through the options and issues involved in connecting such PC-based devices to an MCU-based environment.

By Wolfgang Matthes

More often than not, even a humble project—done for educational, tinkering or just for fun—needs some way to display something and to allow for operator interaction. That means contemplating how best to craft an operator console, a control panel, a display assembly or how to set up a testbed and the like. Solderless breadboards, jumper wire and the ubiquitous small modules were the traditional tools for such efforts—in the past there was no other way than to build real hardware from scratch.

It goes without saying that today’s state-of-the-art technology is characterized by computers with touchscreens and the like. Simply run your favorite flight simulator and compare the cockpits of an old Super Constellation or F-86 aircraft to the cockpits of a Boeing 777 or an F-22. In down-to- earth projects, it is quite natural to think of industrial-grade hardware—industrial PCs, embedded PCs and so on. But those can be way too expensive for our low-budget projects. That’s why we think about using small, inexpensive personal computers (PCs). This topic is best clarified through photos. With that in mind, besides what’s in this article, more photos can be found on Circuit Cellar’s article materials webpage.

Figure 1
Shown here are some jerry-built display and control panels

Figure 1 shows some devices that are essentially basic display and control panels. In most educational, tinkering or fun projects, it’s not practical to spend a lot of time and money to design and build impressive assemblies and panels. More often than not, the problem is solved by more or less sloppy tinkering. In contrast, the devices shown here are somewhat more advanced. They are still jerry-built, but they are crafted with sturdiness as a main objective.

Figure 2
Each of these basic control panels support eight digital outputs operated via toggle switches, and eight inputs whose levels are indicated by LEDs or on an LCD display.

Figure 2 shows three boxes that are basic control panels, each supporting eight inputs and eight outputs. While the device to the left is clearly jerry-built, the two other devices are the result of meticulous mechanical design—they were conducted as experiments (and student assignments) with an intentional disregard of cost. Figure 3 shows the interior of the most sophisticated of the control panels. It supports signal levels between 2.5 V and 24 V, remote operation via the USB and an LCD display. Under program control, it can be operated as a small quasi-static digital tester. When you need more than eight inputs or outputs, attach two or more panels via a USB or serial hub.

Figure 3
The interior of the somewhat more advanced (and expensive) control panel—the result of an exercise in mechanical and PCB design. The ribbon cables connect only the pin headers in the front panel. The PCBs are stacked one above the other, thereby avoiding cables or wiring harnesses.

It goes without saying that such a device is not that cheap. The bill-of-materials (BOM) cost alone could pay for more than one small tablet PC running Windows. Figure 4 shows an 8″ tablet in a purpose-built frame, attached to a test rig and two 7″ tablets in a 19″, 3U subrack. In contrast, those devices are considerably less expensive than the apparatus shown in Figure 3.

Figure 4
These are examples of small Windows tablets adapted to serve as operator consoles, diagnostic displays and testbed controllers.

Employing a PC requires programming skills, but no special craftsmanship or a workshop full of tools. Yes, writing and debugging programs may be challenging. But it’s a lot more forgiving than a mechanical interface where you could accidently turn a front panel into scrap metal, simply due to a misplaced hole or dealing with mismatched connections that only show up when you’re fitting the parts together. …

Read the full article in the September 350 issue of Circuit Cellar
(Full article word count: 4678 words; Figure count: 18 Figures. plus supplemental Figures here.)

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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.

Multi-Channel RF Converter ICs Meet Wireless Carrier Needs

Analog Devices has introduced a mixed-signal front-end (MxFE) RF data converter platform designed to meet the performance needs for a range of wireless equipment such as 4G LTE and 5G millimeter-wave (mmWave) radios. ADI’s new AD9081/2 MxFE platform allows system developers to install multiband radios in the same footprint as single-band radios, which as much as triples call capacity available in today’s 4G LTE base stations. With a 1.2 GHz channel bandwidth, the new MxFE platform also enables wireless carriers that are adding more antennas to their cell towers to meet the higher radio density and data-rate requirements of emerging mmWave 5G.

The AD9081 and AD9082 MxFE devices integrate eight and six RF data converters, respectively, which are manufactured using 28 nm CMOS process technology. Both MxFE options achieve the industry’s widest instantaneous signal bandwidth (up to 2.4 GHz), which simplifies hardware design by reducing the number of frequency translation stages and relaxing filter requirements. This new level of integration addresses the space constraints of wireless device designers by lowering chip count and yielding a 60 percent reduction in printed-circuit-board (PCB) area compared to alternative devices.

By shifting more of the frequency translation and filtering from the analog to the digital domain, the AD9081/2 provides designers with the software configurability to customize their radios. The new multi-channel MxFE platform meets the needs of other wide-bandwidth applications in 5G test and measurement equipment, broadband cable video streaming, multi-antenna phased array radar systems and low-earth-orbit satellite networks.

The MxFE platform processes more of the RF spectrum band and embeds DSP functions on-chip to enable the user to configure the programmable filters and digital up and down conversion blocks to meet specific radio signal bandwidth requirements. This results in a 10X power reduction compared to architectures that perform RF conversion and filtering on the FPGA, while freeing up valuable processor resources or allowing designers to use a more cost-effective FPGA.

The AD9081 is priced at $1,487 (1,000s) and the AD9082 at $1,500. Both will be available for sampling in September 2019.

Analog Devices | www.analog.com

650 W Modular Power Supplies Provide MoPP Isolation

TDK has announced the introduction of the TDK-Lambda brand QM4 modular power supplies rated at 550 W to 650 W. This further extends the QM series which can provide up to 1500 W output power. The QM4 models are available with up to 10 outputs, have full MoPPs (Means of Patient Protection) isolation and low acoustic noise. With medical and industrial safety certifications, the power supplies are suitable for use in medical, test and measurement, communications and broadcast equipment.

Accepting a wide range 90 VAC to 264 VAC, 47-63 Hz input (440 Hz with reduced PFC), the QM4 can deliver 550 W at low line and 650 W with a high line 180-264 VAC input.  With its modular construction, the series can be configured using a simple on-line configurator to provide 1 to 10 independently regulated outputs and include individual output good signal and remote on/off functions. The QM series module output voltages range from 2.8 V to 105.6 V and have output power levels from 300 W to 1200 W. A further subset of option modules provides an AC Fail signal, standby voltages (up to 12 V, up to 2 A), global remote on/off and PMBus communications. Overall case dimensions for the QM4 are 108 mm x 63.3 mm x 270 mm (W x H x D).

The QM4 will operate in ambient temperatures of -20 to +70°C (-40°C start-up), with output power and output current linearly derating above 50°C to 50% at 70°C. With efficiencies of up to 91%, less internal heat is generated allowing the use of a low speed cooling fan to reduce audible noise. A lower airflow speed also significantly reduces the ingress of dirt and other contaminants, improving product reliability. All models in the QM series have a seven-year warranty as standard.

The power supply has 4,000 VAC (2 x MoPPs) input to output, 1,500 VAC (1 x MoPP) input to ground and 1,500 VAC (1 x MoPP) output to ground isolation. All models are certified to the IEC/EN/UL/CSA 60601-1, ANSI/AAMI ES 60601-1 and IEC/EN/UL/CSA 60950-1 safety standards. The QM series is also designed to meet IEC/EN61010-1 with CE marking for the Low Voltage, EMC and RoHS Directives. Earth leakage current is less than 300 µA, and complies with the EN61000-6-3:2007 and EN60601-1-2:2015 (curve B conducted and radiated) emission standards. The units also meet the EN60601-1-2 and EN61000-6-2 immunity standards and are designed and manufactured under the control of ISO9001 and ISO13485 (including risk management).

TDK-Lambda | www.tdk-lambda.com

 

960 W DIN Rail Supply Boasts 95% Efficiency

TDK has announced the addition of a 960 W rated model to its DRF series of AC-DC DIN rail mount power supplies. The high 95% efficiency produces less internal waste heat enabling electrolytic capacitors to run cooler, providing a calculated life of in excess of eleven years with a 75% load at 230Vac input. The unit can supply a peak load of 1440W (24V 60A) for up to 4 seconds to power capacitive and inductive loads. Applications include industrial process control, factory automation, and test and measurement equipment.The power supply has a 24 V output, adjustable from 24 V to 28 V, using either the front panel mounted trim potentiometer or an external 5 to 6V source. The input range is 180 to 264 VAC, withstanding surges of up to 300 VAC for 5 seconds. The operating ambient temperature is -25°C to +70oC, -40°C cold start, derating linearly above 50°C to 75% load at 70°C. The DRF series warranty is five years.

The DRF960-24-1 is 123.4 mm tall, 139 mm deep and has a narrow 110 mm width saving both space on the rail and in the cabinet. Remote on/off and a 30 V 1 A rated DC OK relay contact are provided as standard. When in standby mode using the remote on/off function, the power consumption is less than 1 W. Up to five units can be connected in parallel using the droop mode current share, for systems requiring additional power.

Input to output isolation is 3,000 VAC, input to ground 1500 VAC and output to ground 500 VAC. The DRF960 is certified to the safety standards of IEC/UL/CSA/EN 60950-1, UL508 and is CE marked in accordance to the Low Voltage, EMC and RoHS Directives. The unit is compliant to EN 55032-B (radiated and conducted emissions), EN 61000-3-2 harmonics and IEC 61000-4 immunity standards.

TDK-Lambda | www.tdk-lambda.com

 

April Circuit Cellar: Sneak Preview

The April issue of Circuit Cellar magazine is out next week (March 20th)!. We’ve worked hard to cook up a tasty selection of in-depth embedded electronics articles just for you. We’ll be serving them up to in our 84-page magazine.

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VIDEO AND DISPLAY TECHNOLOGIES IN ACTION

Video Technology in Drones
Because video is the main mission of the majority of commercial drones, video technology has become a center of gravity in today’s drone design decisions. The topic covers everything including single-chip video processing, 4k HD video capture, image stabilization, complex board-level video processing, drone-mounted cameras, hybrid IR/video camera and mesh-networks. In this article, Circuit Cellar’s Editor-in-Chief, Jeff Child, looks at the technology and trends in video technology for drones.

Building an All-in-One Serial Terminal
Many embedded systems require as least some sort of human interface. While Jeff Bachiochi was researching alternatives to mechanical keypads, he came across the touchscreen display products from 4D Systems. He chose their inexpensive, low-power 2.4-inch, resistive touch screen as the basis for his display subsystem project. He makes use of the display’s Espressif Systems ESP8266 processor and Arduino IDE support to turn the display module into a serial terminal with a serial TTL connection to other equipment.

MICROCONTROLLERS ARE EVERYWHERE

Product Focus: 32-Bit Microcontrollers
As the workhorse of today’s embedded systems, 32-bit microcontrollers serve a wide variety of embedded applications-including the IoT. MCU vendors continue to add more connectivity, security and I/O functionality to their 32-bit product families. This Product Focus section updates readers on these trends and provides a product album of representative 32-bit MCU products.

Build a PIC32-Based Recording Studio
In this project article, learn how Cornell students Radhika Chinni, Brandon Quinlan, Raymond Xu built a miniature recording studio using the Microchip PIC32. It can be used as an electric keyboard with the additional functionality of recording and playing back multiple layers of sounds. There is also a microphone that the user can use to make custom recordings.

WONDERFUL WORLD OF WIRELESS

Low-Power Wireless Comms
The growth in demand for IoT solutions has fueled the need for products and technology to do wireless communication from low-power edge devices. Using technologies including Bluetooth Low-Energy (BLE), wireless radio frequency technology (LoRa) and others, embedded system developers are searching for ways to get efficient IoT connectivity while drawing as little power as possible. Circuit Cellar Chief Editor Jeff Child explores the latest technology trends and product developments in low-power wireless communications.

Bluetooth Mesh (Part 2)
Continuing his article series on Bluetooth mesh, this month Bob Japenga looks at the provisioning process required to get a device onto a Bluetooth mesh network. Then he examines two application examples and evaluates the various options for each example.

Build a Prescription Reminder
Pharmaceuticals prescribed by physicians are important to patients both old and young. But these medications will only do their job if taken according to a proper schedule. In this article, Devlin Gualtieri describes his Raspberry-Rx Prescription Reminder project, a network-accessible, the Wi-Fi connected, Raspberry Pi-based device that alerts a person when a particular medication should be administered. It also keeps a log of the actual times when medications were administered.

ENGINEERING TIPS, TRICKS AND TECHNIQUES

The Art of Current Probing
In his February column, Robert Lacoste talked about oscilloscope probes—or more specifically, voltage measurement probes. He explained how selecting the correct probe for a given measurement, and using it as it properly, is as important as having a good scope. In this article, Robert continues the discussion with another common measurement task: Accurately measuring current using an oscilloscope.

Software Engineering
There’s no doubt that achieving high software quality is human-driven endeavor. No amount of automated code development can substitute for best practices. A great tool for such efforts is the IEEE Computer Society’s Guide to the Software Engineering Body of Knowledge. In this article, George Novacek discusses some highlights of this resource, and why he has frequently consulted this document when preparing development plans.

HV Differential Probe
A high-voltage differential probe is a critical piece of test equipment for anyone who wants to safely examine high voltage signals on a standard oscilloscope. In his article, Andrew Levido describes his design of a high-voltage differential probe with features similar to commercial devices, but at a considerably lower cost. It uses just three op amps in a classic instrumentation amplifier configuration and provides a great exercise in precision analog design.

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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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.

120 W and 240 W DIN Rail Power Supplies Boast 93% Efficiency

TDK has announced the introduction of 120 W and 240 W rated models to the DRB series of AC-DC DIN rail mount power supplies. Their narrow width allows additional devices to be installed on the rail, saving cabinet space. The high 93% efficiency produces less internal waste heat enabling electrolytic capacitors to run cooler, extending field operating life to greater than 7 years at 75% load, 230Vac input. Applications include industrial process control, factory automation, semiconductor fabrication and test and measurement equipment.

Rated for continuous operation at 120 W and 240 W, the DRBs can deliver a +20% peak load for up to 10 seconds. The power supplies are currently available with a 24V output, adjustable from 24 V to 28 V, and can accept an 85 to 264 Vac input withstanding surges of up to 300 Vac for 5 seconds. The operating ambient temperature is -25oC to +70oC, -40oC cold start, derating linearly above 55oC to 50% load at 70oC.

In addition to a front panel LED, an isolated DC OK opto-coupled signal is provided to show the output status either locally or remotely. The DRB120 and DRB240 have a rugged metal enclosure measuring 124 mm in height, 125 mm deep and narrow widths of 35 mm and 41 mm respectively.

Input to output isolation is 3,000 Vac, input to ground 1500 Vac and the output to ground is 500Vac. Both models are certified to the safety standards of IEC/UL/CSA/EN 60950-1, IEC/UL/CSA/EN 62368-1, UL508, IEC/EN 62477-1 (OVC III) and are CE marked in accordance to the Low Voltage, EMC and RoHS Directives. The DRBs are compliant to EN55011-B, EN55032-B, CISPR11-B, CISPR22-B, EN61204-3 (Class A) radiated and conducted emissions, EN 61000-3-2 harmonics, IEC 61000-4 immunity and SEMI F47 line dip standards.

TDK Lambda | www.us.tdk-lambda.com

 

February Circuit Cellar: Sneak Preview

The February issue of Circuit Cellar magazine is coming soon. We’ve raised up a bumper crop of in-depth embedded electronics articles just for you, and packed ’em into our 84-page magazine.

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MCUs ARE EVERYWHERE, DOING EVERYTHING

Electronics for Automotive Infotainment
As automotive dashboard displays get more sophisticated, information and entertainment are merging into so-called infotainment systems. That’s driving a need for powerful MCU- and MPU-based solutions that support the connectivity, computing and interfacing needs particular to these system designs. In this article, Circuit Cellar’s Editor-in-Chief, Jeff Child, looks at the technology and trends feuling automotive infotainment.

Inductive Sensing with PSoC MCUs
Inductive sensing is shaping up to be the next big thing for touch technology. It’s suited for applications involving metal-over-touch situations in automotive, industrial and other similar systems. In his article, Nishant Mittal explores the science and technology of inductive sensing. He then describes a complete system design, along with firmware, for an inductive sensing solution based on Cypress Semiconductor’s PSoC microcontroller.

Build a Self-Correcting LED Clock
In North America, most radio-controlled clocks use WWVB’s transmissions to set the correct time. WWVB is a Colorado-based time signal radio station near. Learn how Cornell graduates Eldar Slobodyan and Jason Ben Nathan designed and built a prototype of a Digital WWVB Clock. The project’s main components include a Microchip PIC32 MCU, an external oscillator and a display.

WE’VE GOT THE POWER

Product Focus: ADCs and DACs
Analog-to-digital converters (ADCs) and digital-to-analog converters (DACs) are two of the key IC components that enable digital systems to interact with the real world. Makers of analog ICs are constantly evolving their DAC and ADC chips pushing the barriers of resolution and speeds. This new Product Focus section updates readers on this technology and provides a product album of representative ADC and DAC products.

Building a Generator Control System
Three phase electrical power is a critical technology for heavy machinery. Learn how US Coast Guard Academy students Kent Altobelli and Caleb Stewart built a physical generator set model capable of producing three phase electricity. The article steps through the power sensors, master controller and DC-DC conversion design choices they faced with this project.

EMBEDDED COMPUTING FOR YOUR SYSTEM DESIGN

Non-Standard Single Board Computers
Although standard-form factor embedded computers provide a lot of value, many applications demand that form take priority over function. That’s where non-standard boards shine. The majority of non-standard boards tend to be extremely compact, and well suited for size-constrained system designs. Circuit Cellar Chief Editor Jeff Child explores the latest technology trends and product developments in non-standard SBCs.

Thermal Management in machine learning
Artificial intelligence and machine learning continue to move toward center stage. But the powerful processing they require is tied to high power dissipation that results in a lot of heat to manage. In his article, Tom Gregory from 6SigmaET explores the alternatives available today with a special look at cooling Google’s Tensor Processor Unit 3.0 (TPUv3) which was designed with machine learning in mind.

… AND MORE FROM OUR EXPERT COLUMNISTS

Bluetooth Mesh (Part 1)
Wireless mesh networks are being widely deployed in a wide variety of settings. In this article, Bob Japenga begins his series on Bluetooth mesh. He starts with defining what a mesh network is, then looks at two alternatives available to you as embedded systems designers.

Implementing Time Technology
Many embedded systems need to make use of synchronized time information. In this article, Jeff Bachiochi explores the history of time measurement and how it’s led to NTP and other modern technologies for coordinating universal date and time. Using Arduino and the Espressif System’s ESP32, Jeff then goes through the steps needed to enable your embedded system to request, retrieve and display the synchronized date and time to a display.

Infrared Sensors
Infrared sensing technology has broad application ranging from motion detection in security systems to proximity switches in consumer devices. In this article, George Novacek looks at the science, technology and circuitry of infrared sensors. He also discusses the various types of infrared sensing technologies and how to use them.

The Art of Voltage Probing
Using the right tool for the right job is a basic tenant of electronics engineering. In this article, Robert Lacoste explores one of the most common tools on an engineer’s bench: oscilloscope probes, and in particular the voltage measurement probe. He looks and the different types of voltage probes as well as the techniques to use them effectively and safely.

January Circuit Cellar: Sneak Preview

Happy New Years! The January issue of Circuit Cellar magazine is coming soon. Don’t miss this 1st issue of Circuit Cellar 2019. Enjoy pages and pages of great, in-depth embedded electronics articles.

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

TRENDS & CHOICES IN EMBEDDED COMPUTING

Comms and Control for Drones
Consumer and commercial drones represent one of the most dynamic areas of embedded design today. Chip, board and system suppliers are offering improved ways for drones to do more processing on board the drone, while also providing solutions for implementing the control and communication subsystems in drones. This article by Circuit Cellar’s Editor-in-Chief Jeff Child looks at the technology and products available today that are advancing the capabilities of today’s drones.

Choosing an MPU/MCU for Industrial Design
By Microchip Technology’s Jacko Wilbrink
As MCU performance and functionality improve, the traditional boundaries between MCUs and microprocessor units (MPUs) have become less clear. In this article, Jacko examines the changing landscape in MPU vs. MCU capabilities, OS implications and the specifics of new SiP and SOM approaches for simplifying higher-performance computing requirements in industrial applications.

Product Focus: COM Express Boards
The COM Express architecture has found a solid and growing foothold in embedded systems. COM Express boards provide a complete computing core that can be upgraded when needed, leaving the application-specific I/O on the baseboard. This Product Focus section updates readers on this technology and provides a product album of representative COM Express products.

MICROCONTROLLERS ARE DOING EVERYTHING

Connecting USB to Simple MCUs
By Stuart Ball
Sometimes you want to connect a USB device such as a flash drive to a simple microcontroller. Problem is most MCUs cannot function as a USB host. In this article, Stuart steps through the technology and device choices that solve this challenge. He also puts the idea into action via a project that provides this functionality.

Vision System Enables Overlaid Images
By Daniel Edens and Elise Weir
In this project article, learn how these two Cornell students designed a system to overlay images from a visible light camera and an infrared camera. They use software running on a PIC32 MCU to interface the two types of cameras. The MCU does the computation to create the overlaid images, and displays them on an LCD screen.

DATA ACQUISITION AND MEASUREMENT

Data Acquisition Alternatives
By Jeff Child
While the fundamentals of data acquisition remain the same, its interfacing technology keeps evolving and changing. USB and PCI Express brought data acquisition off the rack, and onto the lab bench top. Today solutions are emerging that leverage Mini PCIe, Thunderbolt and remote web interfacing. Circuit Cellar’s Editor-in-Chief, Jeff Child, dives into the latest technology trends and product developments in data acquisition.

High-Side Current Sensing
By Jeff Bachiochi
Jeff says he likes being able to measure things—for example, being able to measure load current so he can predict how long a battery will last. With that in mind, he recently found a high-side current sensing device, Microchip’s EMC1701. In his article, Jeff takes you through the details of the device and how to make use of it in a battery-based system.

Power Analysis Capture with an MCU
By Colin O’Flynn
Low-cost microcontrollers integrate many powerful peripherals in them. You can even perform data capture directly to internal memory. In his article, Colin uses the ChipWhisperer-Nano as a case study in how you might use such features which would otherwise require external programmable logic.

TOOLS AND TECHNIQUES FOR EMBEDDED SYSTEM DESIGN

Easing into the IoT Cloud (Part 2)
By Brian Millier
In Part 1 of this article series Brian examined some of the technologies and services available today enabling you to ease into the IoT cloud. Now, in Part 2, he discusses the hardware features of the Particle IoT modules, as well as the circuitry and program code for the project. He also explores the integration of a Raspberry Pi solution with the Particle cloud infrastructure.

Hierarchical Menus for Touchscreens
By Aubrey Kagan
In his December article, Aubrey discussed his efforts to build a display subsystem and GUI for embedded use based on a Noritake touchscreen display. This time he shares how he created a menu system within the constraints of the Noritake graphical display system. He explains how he made good use of Microsoft Excel worksheets as a tool for developing the menu system.

Real Schematics (Part 2)
By George Novacek
The first part of this article series on the world of real schematics ended last month with wiring. At high frequencies PCBs suffer from the same parasitic effects as any other type of wiring. You can describe a transmission line as consisting of an infinite number of infinitesimal resistors, inductors and capacitors spread along its entire length. In this article George looks at real schematics from a transmission line perspective.

December Circuit Cellar: Sneak Preview

The December issue of Circuit Cellar magazine is coming soon. Don’t miss this last issue of Circuit Cellar in 2018. Pages and pages of great, in-depth embedded electronics articles prepared for you to enjoy.

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Here’s a sneak preview of December 2018 Circuit Cellar:

AI, FPGAs and EMBEDDED SUPERCOMPUTING

Embedded Supercomputing
Gone are the days when supercomputing levels of processing required a huge, rack-based systems in an air-conditioned room. Today, embedded processors, FPGAs and GPUs are able to do AI and machine learning kinds of operation, enable new types of local decision making in embedded systems. In this article, Circuit Cellar’s Editor-in-Chief, Jeff Child, looks at these technology and trends driving embedded supercomputing.

Convolutional Neural Networks in FPGAs
Deep learning using convolutional neural networks (CNNs) can offer a robust solution across a wide range of applications and market segments. In this article written for Microsemi, Ted Marena illustrates that, while GPUs can be used to implement CNNs, a better approach, especially in edge applications, is to use FPGAs that are aligned with the application’s specific accuracy and performance requirements as well as the available size, cost and power budget.

NOT-TO-BE-OVERLOOKED ENGINEERING ISSUES AND CHOICES

DC-DC Converters
DC-DC conversion products must juggle a lot of masters to push the limits in power density, voltage range and advanced filtering. Issues like the need to accommodate multi-voltage electronics, operate at wide temperature ranges and serve distributed system requirements all add up to some daunting design challenges. This Product Focus section updates readers on these technology trends and provides a product gallery of representative DC-DC converters.

Real Schematics (Part 1)
Our magazine readers know that each issue of Circuit Cellar has several circuit schematics replete with lots of resistors, capacitors, inductors and wiring. But those passive components don’t behave as expected under all circumstances. In this article, George Novacek takes a deep look at the way these components behave with respect to their operating frequency.

Do you speak JTAG?
While most engineers have heard of JTAG or have even used JTAG, there’s some interesting background and capabilities that are so well know. Robert Lacoste examines the history of JTAG and looks at clever ways to use it, for example, using a cheap JTAG probe to toggle pins on your design, or to read the status of a given I/O without writing a single line of code.

PUTTING THE INTERNET-OF-THINGS TO WORK

Industrial IoT Systems
The Industrial Internet-of-Things (IIoT) is a segment of IoT technology where more severe conditions change the game. Rugged gateways and IIoT edge modules comprise these systems where the extreme temperatures and high vibrations of the factory floor make for a demanding environment. Here, Circuit Cellar’s Editor-in-Chief, Jeff Child, looks at key technology and product drives in the IIoT space.

Internet of Things Security (Part 6)
Continuing on with his article series on IoT security, this time Bob Japenga returns to his efforts to craft a checklist to help us create more secure IoT devices. This time he looks at developing a checklist to evaluate the threats to an IoT device.

Applying WebRTC to the IoT
Web Real-time Communications (WebRTC) is an open-source project created by Google that facilitates peer-to-peer communication directly in the web browser and through mobile applications using application programming interfaces. In her article, Callstats.io’s Allie Mellen shows how IoT device communication can be made easy by using WebRTC. With WebRTC, developers can easily enable devices to communicate securely and reliably through video, audio or data transfer.

WI-FI AND BLUETOOTH IN ACTION

IoT Door Security System Uses Wi-Fi
Learn how three Cornell students, Norman Chen, Ram Vellanki and Giacomo Di Liberto, built an Internet connected door security system that grants the user wireless monitoring and control over the system through a web and mobile application. The article discusses the interfacing of a Microchip PIC32 MCU with the Internet and the application of IoT to a door security system.

Self-Navigating Robots Use BLE
Navigating indoors is a difficult but interesting problem. Learn how these two Cornell students, Jane Du and Jacob Glueck, used Received Signal Strength Indicator (RSSI) of Bluetooth Low Energy (BLE) 4.0 chips to enable wheeled, mobile robots to navigate towards a stationary base station. The robot detects its proximity to the station based on the strength of the signal and moves towards what it believes to be the signal source.

IN-DEPTH PROJECT ARTICLES WITH ALL THE DETAILS

Sun Tracking Project
Most solar panel arrays are either fixed-position, or have a limited field of movement. In this project article, Jeff Bachiochi set out to tackle the challenge of a sun tracking system that can move your solar array to wherever the sun is coming from. Jeff’s project is a closed-loop system using severs, opto encoders and the Microchip PIC18 microcontroller.

Designing a Display System for Embedded Use
In this project article, Aubrey Kagan takes us through the process of developing an embedded system user interface subsystem—including everything from display selection to GUI development to MCU control. For the project he chose a 7” Noritake GT800 LCD color display and a Cypress Semiconductor PSoC5LP MCU.

November Circuit Cellar: Sneak Preview

The November issue of Circuit Cellar magazine is coming soon. Clear your decks for a new stack of in-depth embedded electronics articles prepared for you to enjoy.

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SOLUTIONS FOR SYSTEM DESIGNS

3D Printing for Embedded Systems
Although 3D printing for prototyping has existed for decades, it’s only in recent years that it’s become a mainstream tool for embedded systems development. Today the ease of use of these systems has reached new levels and the types of materials that can be used continues to expand. This article by Circuit Cellar’s Editor-in-Chief, Jeff Child looks at the technology and products available today that enable 3D printing for embedded systems.

Add GPS to Your Embedded System
We certainly depend on GPS technology a lot these days, and technology advances have brought fairly powerful GPS functionally into our pockets. Today’s miniaturization of GPS receivers enables you to purchase an inexpensive but capable GPS module that you can add to your embedded system designs. In this article, Stuart Ball shows how to do this and take advantage of the GPS functionality.

FCL for Servo Drives
Servo drives are a key part of many factory automation systems. Improving their precision and speed requires attention to fast-current loops and related functions. In his article, Texas Instruments’ Ramesh Ramamoorthy gives an overview of the functional behavior of the servo loops using fast current loop algorithms in terms of bandwidth and phase margin.

FOCUS ON ANALOG AND POWER

Analog and Mixed-Signal ICs
Analog and mixed-signal ICs play important roles in a variety of applications. These applications depend heavily on all kinds of interfacing between real-world analog signals and the digital realm of processing and control. Circuit Cellar’s Editor-in-Chief, Jeff Child, dives into the latest technology trends and product developments in analog and mixed-signal chips.

Sleeping Electronics
Many of today’s electronic devices are never truly “off.” Even when a device is in sleep mode, it draws some amount of power—and drains batteries. Could this power drain be reduced? In this project article, Jeff Bachiochi addresses this question by looking at more efficient ways to for a system to “play dead” and regulate power.

BUILDING CONNECTED SYSTEMS FOR THE IoT EDGE

Easing into the IoT Cloud (Part 1)
There’s a lot of advantages for the control/monitoring of devices to communicate indirectly with the user interface for those devices—using some form of “always-on” server. When this server is something beyond one in your home, it’s called the “cloud.” Today it’s not that difficult to use an external cloud service to act as the “middleman” in your system design. In this article, Brian Millier looks at the technologies and services available today enabling you to ease in to the IoT cloud.

Sensors at the Intelligent IoT Edge
A new breed of intelligent sensors has emerged aimed squarely at IoT edge subsystems. In this article, Mentor Graphics’ Greg Lebsack explores what defines a sensor as intelligent and steps through the unique design flow issues that surround these kinds of devices.

FUN AND INTERESTING PROJECT ARTICLES

MCU-Based Project Enhances Dance Game
Microcontrollers are perfect for systems that need to process analog signals such as audio and do real-time digital control in conjunction with those signals. Along just those lines, learn how two Cornell students Michael Solomentsev and Drew Dunne recreated the classic arcade game “Dance Dance Revolution” using a Microchip Technology PIC32 MCU. Their version performs wavelet transforms to detect beats from an audio signal to synthesize dance move instructions in real-time without preprocessing.

Building an Autopilot Robot (Part 2)
In part 1 of this two-part article series, Pedro Bertoleti laid the groundwork for his autopiloted four-wheeled robot project by exploring the concept of speed estimation and speed control. In part 2, he dives into the actual building of the robot. The project provides insight to the control and sensing functions of autonomous electrical vehicles.

… AND MORE FROM OUR EXPERT COLUMNISTS

Embedded System Security: Live from Las Vegas
This month Colin O’Flynn summarizes a few interesting presentations from the Black Hat conference in Las Vegas. He walks you through some attacks on bitcoin wallets, x86 backdoors and side channel analysis work—these and other interesting presentations from Black Hat.

Highly Accelerated Product Testing
It’s a fact of life that every electronic system eventually fails. Manufacturers use various methods to weed out most of the initial failures before shipping their product. In this article, George Novacek discusses engineering attempts to bring some predictability into the reliability and life expectancy of electronic systems. In particular, he focuses on Highly Accelerated Lifetime Testing (HALT) and Highly Accelerated Stress Screening (HASS).

September Circuit Cellar: Sneak Preview

The September issue of Circuit Cellar magazine is coming soon. Clear your decks for a new stack of in-depth embedded electronics articles prepared for you to enjoy.

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MOTORS, MOTION CONTROL AND MORE

Motion Control for Robotics
Motion control technology for robotic systems continues to advance, as chip- and board-level solutions evolve to meet new demands. These involve a blending of precise analog technologies to control position, torque and speed with signal processing to enable accurate, real-time motor control. Here, Circuit Cellar’s Editor-in-Chief, Jeff Child, looks the latest technology and product advances in motion control for robotics.

Electronic Speed Control (Part 3)
Radio-controlled drones are one among many applications that depend on the use of an Electronic Speed Controller (ESC) as part of its motor control design. After observing the operation of a number of ESC modules, in this part Jeff Bachiochi focuses in more closely on the interaction of the ESC with the BLDC motor.

BUILDING CONNECTED SYSTEMS

Product Focus: IoT Gateways
IoT gateways are a smart choice to facilitate bidirectional communication between IoT field devices and the cloud. Gateways also provide local processing and storage capabilities for offline services as well as near real-time management and control of edge devices. This Product Focus section updates readers on these technology trends and provides a product gallery of representative IoT gateways.

Wireless Weather Station
Integrating wireless technologies into embedded systems has become much easier these days. In this project article, Raul Alvarez Torrico describes his home-made wireless weather station that monitors ambient temperature, relative humidity, wind speed and wind direction, using Arduino and a pair of cheap Amplitude Shift Keying (ASK) radio modules.

FOCUS ON ANALOG AND POWER TECHNOLOGY

Frequency Modulated DDS
Prompted by a reader’s query, Ed became aware that you can no longer get crystal oscillator modules tuned to specific frequencies. With that in mind, Ed set out to build a “Channel Element” replacement around a Teensy 3.6 board and a DDS module. In this article, Ed Nisley explains how the Teensy’s 32-bit datapath and 180 MHz CPU clock affect the DDS frequency calculations. He then explores some detailed timings.

Power Supplies / Batteries
Sometimes power decisions are left as an afterthought in system designs. But your choice of power supply or battery strategy can have a major impact on your system’s capabilities. Circuit Cellar’s Editor-in-Chief, Jeff Child, dives into the latest technology trends and product developments in power supplies and batteries.

Murphy’s Laws in the DSP World (Part 3)
Unpredictable issues crop up when you move from the real world of analog signals and enter the world of digital signal processing (DSP). In Part 3 of this article series, Mike Smith and Mai Tanaka focuses on strategies for how to—or how to try to—avoid Murphy’s Laws when doing DSP.

SYSTEM DESIGN ISSUES IN VIDEO AND IMAGING

Virtual Emulation for Drones
Drone system designers are integrating high-definition video and other features into their SoCs. Verifying the video capture circuitry, data collection components and UHD-4K streaming video capabilities found in drones is not trivial. In his article, Mentor’s Richard Pugh explains why drone verification is a natural fit for hardware emulation because emulation is very efficient at handling large amounts of streamed data.

LIDAR 3D Imaging on a Budget
Demand is on the rise for 3D image data for use in a variety of applications, from autonomous cars to military base security. That has spurred research into high precision LIDAR systems capable of creating extremely clear 3D images to meet this demand. Learn how Cornell student Chris Graef leveraged inexpensive LIDAR sensors to build a 3D imaging system all within a budget of around $200.

AND MORE FROM OUR EXPERT COLUMNISTS

Velocity and Speed Sensors
Automatic systems require real-life physical attributes to be measured and converted to electrical quantities ready for electronic processing. Velocity is one such attribute. In this article, George Novacek steps through the math, science and technology behind measuring velocity and the sensors used for such measurements.

Recreating the LPC Code Protection Bypass
Microcontroller fuse bits are used to protect code from being read out. How well do they work in practice? Some of them have been recently broken. In this article Colin O’Flynn takes you through the details of such an attack to help you understand the realistic threat model.

August Circuit Cellar: Sneak Preview

The August issue of Circuit Cellar magazine is coming soon. Be on the lookout for a whole shipload of top-notch embedded electronics articles for you to enjoy.

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FPGAs REDEFINE THE DEFINITION OF “SYSTEM”

FPGA System Design
Long gone now are the days when FPGAs were thought of as simple programmable circuitry for interfacing and glue logic. Today, FPGAs are powerful system chips with on-chip processors, signal processing functionality and rich offerings or high-speed connectivity. Here, Circuit Cellar’s Editor-in-Chief, Jeff Child, looks at the latest technology and trends in FPGA system design.

Managing FPGA Design Complexity
Modern FPGAs can contain millions of logic gates and thousands of embedded DSP processors allowing FPGA hardware designers to create extremely sophisticated and complex application-specific hardware functions. In this article, Pentek’s Bob Sgandurra explores how today’s FPGA technology has revamped the roles of both hardware and software engineers as well as how dealing with on-chip IP adds new layers of complexity.

HIGH-INTEGRATION AT THE CHIP-
AND BOARD-LEVEL

Product Focus: Small and Tiny Embedded Boards
An amazing amount of computing functionality can be squeezed on to a small form factor board these days. These company—and even tiny—board-level products meet the needs of applications where extremely low SWaP (size, weight and power) beats all other demands. This Product Focus section updates readers on this technology trend and provides a product album of representative small and tiny embedded boards.

Microcontrollers and Processors
Today’s crop of microcontrollers and embedded processors provide a rich continuum of features, functions and capabilities. It’s hard to tell anymore where the dividing line is, especially when a lot of them use the same CPU cores. Circuit Cellar’s Editor-in-Chief, Jeff Child, delves into the technology and product trends of MCUs and embedded processors.

CAN’T STOP THE SIGNAL

Murphy’s Laws in the DSP World (Part 2)
Many unexpected issues come into play when you move from the real world of analog signals and enter the world of digital signal processing (DSP). Part 2 of this article series by Michael Smith, Mai Tanaka and Ehsan Shahrabi Farahani charges forward introducing “Murphy’s Laws of DSP” #7, #8 and #9 and looks at the spectral analysis of DSP signals.

Signature Analyzer Uses NXP MCU
Doing a signature analysis of a signal used to require an oscilloscope to display your results. In this article, Brian Millier shows how you can build a free-standing tester that uses mostly just the internal peripherals of an NXP ARM microcontroller. He described how the tester operates and how he implemented it using a Teensy 3.5 development module and an intelligent 4.3-inch TFT touch-screen display.

Pitfalls of Filtering Pulsed Signals
Filtering pulsed signals can be a tricky prospect. Using a recent customer implementation as an example, Robert Lacoste highlights various alternative approaches and describes the key concepts involved. Simulation results are provided to help readers understand what’s going on.

PROJECT-BASED STORIES WITH ALL THE DETAILS

Electronic Speed Control (Part 2)
In Part 1, Jeff Bachiochi discussed the mechanical differences between DC brushed and brushless DC (BLDC) motors. This time he dives into basics of an Electronic Speed Controller’s operations and its circuitry. And all this is illustrated via his ESC-based project that uses a Microchip PIC MCU.

Build an Audio Response Light Display
Light shows have been a part of entertainment situations seemingly forever, but the technology has evolved over time. These light shows have their origin in the primitive “light organs” of the 1960s in which each spectral band had its own color that pulsed in intensity with audio amplitudes within its range of frequencies. In this article, Devlin Gualtieri discusses his circuit design that implements a light organ using today’s IC and LED technologies.

AND MORE FROM OUR EXPERT COLUMNISTS

Internet of Things Security (Part 4)
In this next part of his article series on IoT security, Bob Japenga looks at how checklists and the common criteria framework can help us create more secure IoT devices. He covers how to create a list of security assets and to establish threat checklists that identify all the threats to your security assets.

Thermoelectric Cooling (Part 2)
In Part 1 George Novacek described how he built a test chamber using some electronics combined with components salvaged from his thermoelectric water cooler. To confirm his test results, he purchased another thermoelectric cooler and repeated the tests. In Part 2 he covers the results of these tests along with some theoretical performance calculations.

Component Tolerance

Accuracy Unmasked

We take for granted sometimes that the tolerances of our electronic components fit the needs of our designs. In this article, Robert takes a deep look into the subject of tolerances, using the simple resistor as an example. He goes through the math to help you better understand accuracy and drift along with other factors.

By Robert Lacoste

One of the last projects I worked on with my colleagues was a kind of high-precision current meter. It turned out to be far more difficult than anticipated, even with our combined experience totaling almost 100 years. Maybe this has happened with your projects too: You discover that, even when you’re not looking for top performance out of your electronic components, the accuracy and stability of those components can be pernicious. My topic this month is examining component tolerances. And, for simplicity, I will focus on the simplest possible electronic device: a resistor.

FIGURE 1 A very simple voltage divider. With these values, Uout will be 1 V with Uin=100 V

Let’s start with a basic application. Imagine that you have to design a voltage divider with a ratio of 1/100 (Figure 1). I will assume that the source impedance is very low and that the load connected on the output draws no current at all. With those parameters the calculations are very easy. You just need to know Ohm’s Law. Because the resistors are in series, the current circulating through the two resistors is:

Similarly, the output voltage is:

Given that the current I is the same in both equations, we get:

This circuit is indeed a voltage divider, with a ratio of R2/(R1+R2). We want a ratio of 1/100, so one resistor could be fixed arbitrarily and the second easily calculated. For example: R1=9,900 Ω and R2=100 Ω will do the job as:

Of course, you can easily simulate such a circuit with any SPICE-based circuit simulator if you wish. I personally used Proteus from Labcenter to draw and simulate the small schematic provided on Figure 1, and the output voltage is 1 V with 100 V applied on the input, as expected. As usual, I encourage you to reproduce these small examples with your preferred simulator: for example the free LT-Spice.

Now let’s talk about accuracy. You want your divider to be as precise as possible and therefore you want to buy reasonably accurate resistors. But what if your budget is constrained? Will you use a high accuracy resistor for R1 (9,900 Ω)? Or for R2 (100 Ω)? Or for both? The good answer is both. In that case, a 1% error on either R1 or R2 gives close to a 1% error of the output voltage, as shown in Figure 2. Even if R1 has a stranger value than R2—9,900 Ω vs. 100 Ω—their accuracy is just as critical.

Figure 2
A 1% error either on the top or bottom resistors will induce a roughly 1% error on the output. That would not be the case for other division ratios.

Maybe you think this is too obvious? In that case I will give you another exercise: What happens with a divide-by-2 circuit using two resistors of the same value? Do the calculation or simulate it and you will find that both resistors have still the same impact on accuracy. But now a 1% error on one of the resistors has only a 0.5% impact on the output voltage. That means you could buy slightly less expensive resistors for the same overall precision! In fact, the higher the division ratio, the higher is the impact of each resistor on the overall accuracy.

E Series Resistors

Let’s go back to the 1/100 divider example. If you want to build it and look for a
9,900-Ω resistor, you will have some difficulties because nobody sells them.. …

Read the full article in the April 333 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.

March Circuit Cellar: Sneak Preview

The March issue of Circuit Cellar magazine is coming soon. And we’ve got a healthy serving of embedded electronics articles for you. Here’s a sneak peak.

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TECHNOLOGY FOR THE INTERNET-OF-THINGS

IoT: From Device to Gateway
The Internet of Things (IoT) is one of the most dynamic areas of embedded systems design today. This feature focuses on the technologies and products from edge IoT devices up to IoT gateways. Circuit Cellar Chief Editor Jeff Child examines the wireless technologies, sensors, edge devices and IoT gateway technologies at the center of this phenomenon.

Texting and IoT Embedded Devices
Texting has become a huge part of our daily lives. But can texting be leveraged for use in IoT Wi-Fi devices? Jeff Bachiochi lays the groundwork for describing a project that will involve texting. In this part, he gets into out the details for getting started with a look at Espressif System’s ESP8266EX SoC.

Exploring the ESP32’s Peripheral Blocks
What makes an embedded processor suitable as an IoT or home control device? Wi-Fi support is just part of the picture. Brian Millier has done some Wi-Fi projects using the ESP32, so here he shares his insights about the peripherals on the ESP32 and why they’re so powerful.

MICROCONTROLLERS HERE, THERE & EVERYWHERE

Designing a Home Cleaning Robot (Part 4)
In this final part of his four-part article series about building a home cleaning robot, Nishant Mittal discusses the firmware part of the system and gets into the system’s actual operation. The robot is based on Cypress Semiconductor’s PSoC microcontroller.

Apartment Entry System Uses PIC32
Learn how a Cornell undergraduate built a system that enables an apartment resident to enter when keys are lost or to grant access to a guest when there’s no one home. The system consists of a microphone connected to a Microchip PIC32 MCU that controls a push solenoid to actuate the unlock button.

Posture Corrector Leverages Bluetooth
Learn how these Cornell students built a posture corrector that helps remind you to sit up straight. Using vibration and visual cues, this wearable device is paired with a phone app and makes use of Bluetooth and Microchip PIC32 technology.

INTERACTING WITH THE ANALOG WORLD

Product Focus: ADCs and DACs
Makers of analog ICs are constantly evolving their DAC and ADC chips pushing the barriers of resolution and speeds. This new Product Focus section updates readers on this technology and provides a product album of representative ADC and DAC products.

Stepper Motor Waveforms
Using inexpensive microcontrollers, motor drivers, stepper motors and other hardware, columnist Ed Nisley built himself a Computer Numeric Control (CNC) machines. In this article Ed examines how the CNC’s stepper motors perform, then pushes one well beyond its normal limits.

Measuring Acceleration
Sensors are a fundamental part of what make smart machines smart. And accelerometers are one of the most important of these. In this article, George Novacek examines the principles behind accelerometers and how the technology works.

SOFTWARE TOOLS AND PROTOTYPING

Trace and Code Coverage Tools
Today it’s not uncommon for embedded devices to have millions of lines of software code. Trace and code coverage tools have kept pace with these demands making it easier for embedded developers to analyze, debug and verify complex embedded software. Circuit Cellar Chief Editor Jeff Child explores the latest technology trends and product developments in trace and code coverage tools.

Manual Pick-n-Place Assembly Helper
Prototyping embedded systems is an important part of the development cycle. In this article, Colin O’Flynn presents an open-source tool that helps you assemble prototype devices by making the placement process even easier.