Tuesday’s Newsletter: IoT Tech Focus

Coming to your inbox tomorrow: Circuit Cellar’s IoT Technology Focus newsletter. Tomorrow’s newsletter covers what’s happening with Internet-of-Things (IoT) technology–-from devices to gateway networks to cloud architectures. This newsletter tackles news and trends about the products and technologies needed to build IoT implementations and devices.

Bonus: We’ve added Drawings for Free Stuff to our weekly newsletters. Make sure you’ve subscribed to the newsletter so you can participate.

Already a Circuit Cellar Newsletter subscriber? Great!
You’ll get your IoT Technology Focus newsletter issue tomorrow.

Not a Circuit Cellar Newsletter subscriber?
Don’t be left out! Sign up now:

Our weekly Circuit Cellar Newsletter will switch its theme each week, so look for these in upcoming weeks:

Embedded Boards.(10/23) The focus here is on both standard and non-standard embedded computer boards that ease prototyping efforts and let you smoothly scale up to production volumes.

October has a 5th Tuesday, so we’re bringing you a bonus newsletter:
Digital Signage (10/30)  Digital signage ranks among the most dynamic areas of today’s embedded computing space. Makers of digital signage players, board-level products and other technologies continue to roll out new solutions for implementing powerful digital signage systems. This newsletter looks at the latest technology trends and product developments in digital signage.

Analog & Power. (11/6) This newsletter content zeros in on the latest developments in analog and power technologies including DC-DC converters, AD-DC converters, power supplies, op amps, batteries and more.

Microcontroller Watch (11/13) This newsletter keeps you up-to-date on latest microcontroller news. In this section, we examine the microcontrollers along with their associated tools and support products.

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.

Not a Circuit Cellar subscriber?  Don’t be left out! Sign up today:

 

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

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).

IAR Updates Dev Tools for Renesas Automotive MCUs

IAR Systems has announced a major update of its development tools for Renesas automotive-focused RH850 microcontrollers. The latest version of the complete C/C++ compiler and debugger toolchain IAR Embedded Workbench for Renesas RH850 offers boosted user experience and extended capabilities through a number of new features.

IAR Embedded Workbench for Renesas RH850 incorporates a compiler, a debugger, an assembler and a linker in one integrated development environment. It is available in several editions to suit different company needs, including a functional safety edition certified by TÜV SÜD according to IEC 61508, ISO 26262 and EN 50128. Renesas Electronics’ RH850 automotive MCU family includes rich functional safety and embedded security features needed for advanced automotive applications.
Version 2.10 of IAR Embedded Workbench for Renesas RH850 adds compliance with the latest C language standard ISO/IEC 9899:2011 and the latest C++ standard ISO/IEC 14882:2014, ensuring high-quality, future-proof code. Renowned for producing very efficient code, the IAR C/C++ Compiler™ in IAR Embedded Workbench for Renesas RH850 now supports stack protection and stack usage analysis functionality. Available as an add-on for the toolchain is the static analysis tool C-STAT, which is now updated with a number of new checks. With these additions, developers building RH850-based applications are able to further strengthen code quality, stability and reliability in their embedded applications.

Automotive embedded applications are growing in complexity, which means it can be challenging to make a correct setup of peripherals from scratch. The Renesas Smart Configurator is a tool for combining software, automatically generating control programs for peripheral modules, and pin setting from the GUI with built-in cross-checks to avoid potential contention with multiplexed functions. In version 2.10 of IAR Embedded Workbench for Renesas RH850, automated code generation from Renesas Smart Configurator is made possible through the straight-forward project connection functionality.

IAR Systems | www.iar.com

Firms Team to Teach Implementing Power Supplies on STM32 MCUs

STMicroelectronics and Biricha Digital Power, an industrial training and consultancy company focused on switched power design and EMC, have developed a workshop to show power-supply engineers why and how to quickly move to a digital implementation. The workshop, aimed at analog PSU (Power Supply Unit) designers and embedded-system engineers who need to build high-performance, stable digital power supplies and Digital PFCs (Power Factor Corrections), will be based on a complementary portfolio of tailored hardware, software, tools, labs and detailed training documentation.

This includes the STM32F334 product line (with its high-resolution timer – 217 ps), a member of ST’s STM32 family of more than 800 MCUs covering the full spectrum from ultra-low power to high performance and supporting ecosystem, combined with Biricha’s Power Supply and PFC design software.

Key sessions will demonstrate how to quickly design digital power supplies and power factor correction from scratch, and how to design stable digital control loops for both voltage and current mode DC/DC and PFC applications. Workshop participants will get a chance to design, code, implement, and test several digital power supplies. The first workshop, an all-inclusive 4-day course hosted by Future Electronics, is scheduled for November 27-30, 2018 in Munich, Germany.

Biricha Digital Power | www.biricha.com

STMicroelectronics | www.st.com

MCUs Provide Inductive Sensing Solution

Cypress Semiconductor has announced production availability of the PSoC 4700S series of microcontrollers that use MagSense inductive sensing technology for contactless metal sensing. The series also incorporates Cypress’ industry-leading CapSense capacitive-sensing technology, empowering consumer, industrial, and automotive product developers to create sleek, state-of-the-art designs using metals and other materials. The highly-integrated MCUs enable cost-efficient system designs by reducing bill-of-material costs and provide superior noise immunity for reliable operation, even in extreme environmental conditions.
Cypress also announced availability of the new CY8CKIT-148 PSoC 4700S Inductive Sensing Evaluation Kit, a low-cost hardware platform that enables design and debug of the MCUs. The kit includes MagSense inductive-sensing buttons and a proximity sensor, as well as an FPC connector to evaluate various coils, such as a rotary encoder. The PSoC 4700S series is supported in Cypress’ PSoC Creator Integrated Design Environment (IDE), which allows users to drag and drop production-ready hardware blocks, including the MagSense inductive sensing capability, into a design and configure them easily via a simple graphical user interface.

The PSoC 4700S MCUs integrate:

  • A 32-bit Arm Cortex-M0+ core
  • Up to 32 KB Flash and 4 KB SRAM
  • 36 GPIOs
  • 7 programmable analog blocks
  • 7 programmable digital blocks

Support for up to 16 sensors, enabling implementation of buttons, linear and rotary encoders, and proximity sensing.

The CY8CKIT-148 PSoC 4700S Inductive Sensing Evaluation Kit is available for $49 at the Cypress online store and from select distributors.

Cypress Semiconductor | www.cypress.com

AVR Microcontrollers Get MPLAB X IDE Support

Designers who have traditionally used Microchip’s PIC microcontrollers and developed with the MPLAB ecosystem can now easily evaluate and incorporate AVR® MCUs into their applications. The majority of AVR MCUs are now beta supported with the release of MPLAB X Integrated Development Environment (IDE) version 5.05, available now from Microchip Technology. Support for additional AVR MCUs and enhancements will be added in future MPLAB versions. AVR support will continue to be added to Atmel Studio 7 and Atmel START for current and future AVR devices.

MPLAB X IDE version 5.05 provides a unified development experience that is both cross-platform and scalable with compatibility on Windows, macOS and Linux operating systems, allowing designers to develop with AVR MCUs on their hardware system of choice. The tool chain has been enhanced with support for Microchip’s code configuration tool, MPLAB Code Configurator (MCC), making it easy for developers to configure software components and device settings such as clocks, peripherals and pin layout with the tools’ menu-driven interface. MCC can also generate code for specific development boards, such as Microchip’s Curiosity ATmega4809 Nano (DM320115) development board and existing AVR Xplained development boards.

More compiler choices and debugger/programmer options are also available when compiling and programming AVR MCUs using MPLAB X IDE 5.05. Compiler choices include the AVR MCU GNU Compiler Collection (GCC) or the MPLAB XC8 C Compiler, providing developers with additional advanced software optimization techniques to reduce code size. Designers can also accelerate debugging and programming using MPLAB PICki 4 programmer/debugger tool or the newly released MPLAB Snap programmer/debugger tool.

The majority of development boards available to evaluate and program AVR MCUs are supported by the MPLAB ecosystem and MCC. Xplained development boards are compatible with START and are now compatible with MPLAB X IDE. Xplained development boards are cost-effective, fully integrated MCU development platforms targeted at first-time users, makers, and those seeking a feature-rich rapid prototyping board. The Xplained platform includes an integrated programmer/debugger and requires no additional hardware to get started.

MPLAB X IDE version 5.05, MPLAB XC8 C Compiler and AVR MCU GCC are available for free on Microchip’s website. The MPLAB PICkit 4 (PG164140) development tool is available today for $47.95. The MPLAB Snap (PG164100) is available today for $14.95. The ATmega4809 Curiosity Nano board (DM320115) is available today for $10.00.

Microchip Technology | www.microchip.com

NXP i.MX RT1060 Crossover Processors Released

First announced in February at Embedded World 2018, NXP Semiconductors has released its i.MX RT1060 Crossover processor, with the company claiming a mere ten months from concept to market launch.

The i.MX RT1060 is the latest addition to what NXP calls a crossover processor series and expands the i.MX RT series to three scalable families. The i.MX RT1060 doubles the On-Chip SRAM to 1 MB while keeping pin-to-pin compatibility with i.MX RT1050. This new series introduces additional features ideal for real-time applications such as High-Speed GPIO, CAN-FD, and synchronous parallel NAND/NOR/PSRAM controller. The i.MX RT1060 runs on the Arm Cortex-M7 core at 600 MHz.

This device is fully supported by NXP’s MCUXpresso Software and Tools, a comprehensive and cohesive set of free software development tools for Kinetis, LPC and i.MX RT microcontrollers. MCUXpresso SDK also includes project files for Keil MDK and IAR EWARM.

The i.MX RT crossover are designed to bridge the gap between high-performance and integration while minimizing costs to meet today’s need for high performance embedded processing at the edge node. According to NXP the series were designed to combine high performance MCU processing with the functionality of applications processors, at reduced costs, thereby enabling advanced computation and machine learning capabilities in millions of connected edge devices. The i.MX RT1060 is available now, and is priced at $3.48 (10,000s).

NXP Semiconductors | www.nxp.com

Tuesday’s Newsletter: Microcontroller Watch

Coming to your inbox tomorrow: Circuit Cellar’s Microcontroller Watch newsletter. Tomorrow’s newsletter keeps you up-to-date on latest microcontroller news. In this section, we examine the microcontrollers along with their associated tools and support products.

Bonus: We’ve added Drawings for Free Stuff to our weekly newsletters. Make sure you’ve subscribed to the newsletter so you can participate.

Already a Circuit Cellar Newsletter subscriber? Great!
You’ll get your Microcontroller Watch newsletter issue tomorrow.

Not a Circuit Cellar Newsletter subscriber?
Don’t be left out! Sign up now:

Our weekly Circuit Cellar Newsletter will switch its theme each week, so look for these in upcoming weeks:

IoT Technology Focus. (10/16) Covers what’s happening with Internet-of-Things (IoT) technology–-from devices to gateway networks to cloud architectures. This newsletter tackles news and trends about the products and technologies needed to build IoT implementations and devices.

Embedded Boards.(10/23) The focus here is on both standard and non-standard embedded computer boards that ease prototyping efforts and let you smoothly scale up to production volumes.

October has a 5th Tuesday, so we’re bringing you a bonus newsletter:
Digital Signage (10/30)  Digital signage ranks among the most dynamic areas of today’s embedded computing space. Makers of digital signage players, board-level products and other technologies continue to roll out new solutions for implementing powerful digital signage systems. This newsletter looks at the latest technology trends and product developments in digital signage.

Analog & Power. (11/6) This newsletter content zeros in on the latest developments in analog and power technologies including DC-DC converters, AD-DC converters, power supplies, op amps, batteries and more.

Security Takes Center Stage for MCUs

Enabling Secure IoT

Embedded systems face security challenges unlike those in the IT realm. To meet those needs, microcontroller vendors continue to add ever-more sophisticated security features to their devices—both on their own and via partnerships with security specialists.

By Jeff Child, Editor-in-Chief

For embedded systems, there is no one piece of technology that can take on all the security responsibilities of a system on their own. Indeed, everything from application software to firmware to data storage has a role to play in security. That said, microcontollers have been trending toward assuming a central role in embedded security. One driving factor for this is the Internet-of-Things (IoT). As the IoT era moves into full gear, all kinds of devices are getting more connected. And because MCUs are a key component in those connected systems, MCUs have evolved in recent years to include more robust security features on chip.

That trend has continued over the last 12 months, with the leading MCU vendors ramping up those embedded security capabilities in a variety of ways—some on their own and some by teaming up with hardware and software security specialists.

Built for IoT Security

Exemplifying these trends, Microchip Technology in June released its SAM L10 and SAM L11 MCU families (Figure 1). The devices were designed to address the increasing risks of exposing intellectual property (IP) and sensitive information in IoT-based embedded systems. The MCU families are based on the Arm Cortex-M23 core, with the SAM L11 featuring Arm TrustZone for Armv8-M, a programmable environment that provides hardware isolation between certified libraries, IP and application code. Security features on the MCUs include tamper resistance, secure boot and secure key storage. These, combined with TrustZone technology, protect applications from both remote and physical attacks.

Figure 1
The SAM L10 and SAM L11 MCU families provide TrustZone for Armv8-M hardware isolation between certified libraries, IP and application code. The MCUs also feature tamper resistance, secure boot and secure key storage.

In addition to TrustZone technology, the SAM L11 security features include an on-board cryptographic module supporting Advanced Encryption Standard (AES), Galois Counter Mode (GCM) and Secure Hash Algorithm (SHA). The secure boot and secure key storage with tamper detection capabilities establish a hardware root of trust. It also offers a secure bootloader for secure firmware upgrades.

Microchip has partnered with Trustonic, a member of Microchip’s Security Design Partner Program, to offer a comprehensive security solution framework that simplifies implementation of security and enables customers to introduce end products faster. Microchip has also partnered with Secure Thingz and Data I/O Corporation to offer secure provisioning services for SAM L11 customers that have a proven security framework.

Wireless MCU

Likewise focusing on IoT security, NXP Semiconductor in February announced its K32W0x wireless MCU platform. According to NXP, it’s the first single-chip device with a dual-core architecture and embedded multi-protocol radio. It provides a solution for miniaturizing sophisticated applications that typically require a larger, more costly two-chip solution. Examples include consumer devices such as wearables, smart door locks, thermostats and other smart home devices.

The K32W0x embeds a dual-core architecture comprised of an Arm Cortex-M4 core for high performance application processing and a Cortex-M0+ core for low-power connectivity and sensor processing. Memory on chip includes 1.25 MB of flash and 384 KB of SRAM. Its multi-protocol radio supports Bluetooth 5 and IEEE 802.15.4 including the Thread IP-based mesh networking stack and the Zigbee 3.0 mesh networking stack.

Figure 2
Security features of the K32W0x MCU include a cryptographic sub-system that has a dedicated core, dedicated instruction and data memory for encryption, signing and hashing algorithms including AES, DES, SHA, RSA and ECC.

Features of the K32W0x’s security system include a cryptographic sub-system that has a dedicated core, dedicated instruction and data memory for encryption, signing and hashing algorithms including AES, DES, SHA, RSA and ECC. Secure key management is provided for storing and protecting sensitive security keys (Figure 2). Support is enabled for erasing the cryptographic sub-system memory, including security keys, upon sensing a security breach or physical tamper event. The device has a Resource Domain Controller for access control, system memory protection and peripheral isolation. Built-in secure boot and secure over-the-air programming is supported to assure only authorized and authenticated code runs in the device.

To extend the on-chip security features of the K32W0x MCU platform, NXP has collaborated with B-Secur, an expert in biometric authentication, to develop a system that uses an individual’s unique heart pattern (electrocardiogram/ECG) to validate identity, making systems more secure than using an individual’s fingerprint or voice.

IP Boosts Security

For its part, Renesas Electronics addressed the IoT security challenge late last year when it expanded its RX65N/RX651 Group MCU lineup.  …

Read the full article in the October 339 issue of Circuit Cellar

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.

Tuesday’s Newsletter: Analog & Power

Coming to your inbox tomorrow: Circuit Cellar’s Analog & Power newsletter. Tomorrow’s newsletter content zeros in on the latest developments in analog and power technologies including ADCs, DACs, DC-DC converters, AD-DC converters, power supplies, op amps, batteries and more.

Bonus: We’ve added Drawings for Free Stuff to our weekly newsletters. Make sure you’ve subscribed to the newsletter so you can participate.

Already a Circuit Cellar Newsletter subscriber? Great!
You’ll get your Analog & Power newsletter issue tomorrow.

Not a Circuit Cellar Newsletter subscriber?
Don’t be left out! Sign up now:

Our weekly Circuit Cellar Newsletter will switch its theme each week, so look for these in upcoming weeks:

Microcontroller Watch. (10/9) This newsletter keeps you up-to-date on latest microcontroller news. In this section, we examine the microcontrollers along with their associated tools and support products.

IoT Technology Focus. (10/16) Covers what’s happening with Internet-of-Things (IoT) technology–-from devices to gateway networks to cloud architectures. This newsletter tackles news and trends about the products and technologies needed to build IoT implementations and devices.

Embedded Boards.(10/23) The focus here is on both standard and non-standard embedded computer boards that ease prototyping efforts and let you smoothly scale up to production volumes.

October has a 5th Tuesday, so we’re bringing you a bonus newsletter:
Digital Signage (10/30)  Digital signage ranks among the most dynamic areas of today’s embedded computing space. Makers of digital signage players, board-level products and other technologies continue to roll out new solutions for implementing powerful digital signage systems. This newsletter looks at the latest technology trends and product developments in digital signage.

ST and TomTom Team Up for Geolocation Tool Solution

STMicroelectronics and TomTom, a location technology specialist, have  announced a package of development tools in the STM32 Open Development Environment that connect directly to TomTom Maps APIs (Application Programming Interfaces) for location, tracking and mapping data services. It is aimed at accelerating product development and reducing time-to-market and development costs for developers.

This development package consists of an STM32 Discovery host board for 2G/3G cellular-to-cloud connectivity (shown), a GNSS expansion board based on ST’s Teseo satellite navigation technology, and a software Function Pack that connects your Internet-of-Things (IoT) node via a cellular network to a range of TomTom Maps APIs. With this hardware and software package and a TomTom developer account, developers can quickly add location-based services to their IoT and Smart City applications. Among these services are the translation of GPS coordinates into a street address inside a map (Reverse Geocoding), retrieval of nearby point of interests, and the production of accurate navigation directions.

In addition to the STM32 family of Arm Cortex-M core microcontrollers, the development tools leverage ST’s multi-constellation Teseo positioning-receiver technology to perform all positioning operations including tracking, acquisition, navigation and data output.

For mapping data and services, technology companies, geographical information systems (GIS) providers, government bodies, and traffic-management institutions across the globe rely on TomTom to deliver industry-leading mapping products that create location-enabled applications.

STMicroelectronics | www.st.com

Build a Persistence-of-Vision Display

Using LEDs and PIC32

Learn how these two Cornell University students created a persistence-of-vision (POV) display. They found a way to fit an LED strip onto the mechanically rigid base of a box window fan. The POV display creates the illusion of an image and show anything from an analog clock to ASCII text and complex images.

By Han Li and Emily Sun

Visual feedback is a key aspect of human interaction in everyday life. With technology, the beauty of the visual world can be preserved with images and videos. We set out to create a persistence-of-vision (POV) display that is both multifunctional and easy to use, through the use of a large box fan. Box fans are often found by the window on hot summer days, and can be quite unique with the integration of a “cool” POV display. For our project, we found a way to fit a DotStar LED strip onto the mechanically rigid box base of a box fan. As such, the box fan serves as an ideal platform for a POV display, without needing to construct a well-calibrated rotating setup with a DC motor. The box fan also has preset settings for speed which is convenient for testing.

The novelty of this POV display makes it a good conversation starter, and it can be easily assembled and customized. The display creates an illusion of an image and shows anything from an analog clock to ASCII text and complex images.

In designing our POV fan display, the first thing we measured was the fan’s speed of rotation. This was calculated by flashing a blinking strobe light through the fan blades. On the slowest setting, the fan rotates at approximately 7 Hz, which is equivalent to 143 ms per rotation around the circular radius of the spinning fan. The angle resolution of the image generator of the POV display is limited by time constraints, so we defined 100 tick locations around the peripheral of the fan. Since the LEDs are programmed to light up twice per rotation, the images can be rendered twice as fast, thus increasing the refresh rate of the display to around 14 Hz—each pixel is blinking 14 times per second. For the human eye, the POV effect is achieved around 15 Hz, which means we are getting a decent result with our setup.

With an interrupt time of approximately 1 ms, and through the use of the Hall effect sensor that updates the period on each rotation, the positioning of displayed elements on the fan varies to at most 2.5 degrees. During testing, there are no observations of rotational jittering greater than 2.5 degrees with 100 display angles.

HARDWARE DESIGN

The hardware components are a box fan, DotStar LED strip, tri-state buffer, Hall effect sensor, 5 V battery bank, 9 V battery, a piece of 0.635 cm × 2.54 cm × 50 cm plywood and a Microchip Technology PIC32 microcontroller on a custom PCB [1].

Figure 1
Hardware setup with a closeup of Hall effect sensor and magnet placement

The custom PCB with the mounted PIC32 is secured onto the protoboard above a piece of Styrofoam to prevent short-circuiting (Figure 1). The protoboard itself contains the necessary power distribution and level shifting required for the LED strip. The DotStar LED strip must be driven at 5 V and takes about 60 mA per LED at full intensity. Because of the PIC32’s 3.3 V output, an ON Semiconductor 74LS125 tri-state buffer [2] is used as a level shifter. This is done by shorting the gate on the tri-state buffer to ground and powering the buffer with the 5 V rail (Figure 2). The 9 V battery is then connected directly to the custom PCB with the adapter, and the 5 V battery pack is connected to the power rail on the protoboard (Figure 1).

Figure 2
Schematic of hardware setup

In terms of mechanical setup, the front-facing grill on the box fan is removed for easy access. A piece of plywood is mounted onto the fan with two wood screws on the opposite side of the fan’s plastic centerpiece. The DotStar LED strip is secured to the plywood with zip ties. The metal ridges that secure the front facing grills are bent outward to allow for smooth rotation of the mounted plywood piece.  …

Read the full article in the October 339 issue of Circuit Cellar

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.

Mouser Stocking Microchip’s MPLAB Snap Development Tool

Global distributor Mouser Electronics is now stocking the MPLAB Snap in-circuit debugger and programmer from Microchip Technology. The MPLAB Snap provides affordable, fast, and easy debugging and programming of most PIC, AVR and SAM flash microcontrollers and dsPIC digital signal controllers (DSCs), using the powerful graphical user interface of MPLAB X integrated development environment (IDE).
The Microchip MPLAB Snap board, available from Mouser Electronics, features a powerful 32-bit 300 MHz SAM E70 Arm Cortex-M7 based microcontroller for quicker debug iterations. The debugger system executes code, like an actual device, because it uses the target device’s built-in emulation circuitry, instead of a special debugger chip. All available features of the device are accessible interactively and can be set and modified by the MPLAB X IDE interface. Additionally, the board matches the silicon clocking speed of the target device, allowing engineers to run programs at the device’s maximum speed.

The board connects to a computer via high-speed USB 2.0 interface and can be connected to the target device through an 8-pin single in-line (SIL) header. The connector uses two device input/output (I/O) pins and the reset line to implement in-circuit debugging and In-Circuit Serial Programming (ICSP™) capability. Along with its support for a wide target voltage range of 1.20 V to 5.5 V, the MPLAB Snap supports advanced interfaces such as 4-wire JTAG and Serial Wire Debug with streaming data gateway. It is also backward compatible for demo boards, headers and target systems using 2-wire JTAG and ICSP.

Microchip Technology | www.microchip.com

Mouser Electronics | www.mouser.com

Next Newsletter: Embedded Boards

Coming to your inbox tomorrow: Circuit Cellar’s Embedded Boards newsletter. Tomorrow’s newsletter content focuses on both standard and non-standard embedded computer boards that ease prototyping efforts and let you smoothly scale up to production volumes.

Bonus: We’ve added Drawings for Free Stuff to our weekly newsletters. Make sure you’ve subscribed to the newsletter so you can participate.

Already a Circuit Cellar Newsletter subscriber? Great!
You’ll get your
Embedded Boards newsletter issue tomorrow.

Not a Circuit Cellar Newsletter subscriber?
Don’t be left out! Sign up now:

Our weekly Circuit Cellar Newsletter will switch its theme each week, so look for these in upcoming weeks:

Analog & Power. (10/2) This newsletter content zeros in on the latest developments in analog and power technologies including DC-DC converters, AD-DC converters, power supplies, op amps, batteries and more.

Microcontroller Watch (10/9) This newsletter keeps you up-to-date on latest microcontroller news. In this section, we examine the microcontrollers along with their associated tools and support products.

IoT Technology Focus. (10/16) Covers what’s happening with Internet-of-Things (IoT) technology–-from devices to gateway networks to cloud architectures. This newsletter tackles news and trends about the products and technologies needed to build IoT implementations and devices.

Tuesday’s Newsletter: IoT Tech Focus

Coming to your inbox tomorrow: Circuit Cellar’s IoT Technology Focus newsletter. Tomorrow’s newsletter covers what’s happening with Internet-of-Things (IoT) technology–-from devices to gateway networks to cloud architectures. This newsletter tackles news and trends about the products and technologies needed to build IoT implementations and devices.

Bonus: We’ve added Drawings for Free Stuff to our weekly newsletters. Make sure you’ve subscribed to the newsletter so you can participate.

Already a Circuit Cellar Newsletter subscriber? Great!
You’ll get your IoT Technology Focus newsletter issue tomorrow.

Not a Circuit Cellar Newsletter subscriber?
Don’t be left out! Sign up now:

Our weekly Circuit Cellar Newsletter will switch its theme each week, so look for these in upcoming weeks:

Embedded Boards.(9/25) The focus here is on both standard and non-standard embedded computer boards that ease prototyping efforts and let you smoothly scale up to production volumes.

Analog & Power. (10/2) This newsletter content zeros in on the latest developments in analog and power technologies including DC-DC converters, AD-DC converters, power supplies, op amps, batteries and more.

Microcontroller Watch (10/9) This newsletter keeps you up-to-date on latest microcontroller news. In this section, we examine the microcontrollers along with their associated tools and support products.