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Analog & Power. (7/2) This newsletter content zeros in on the latest developments in analog and power technologies including DC-DC converters, AC-DC converters, power supplies, op amps, batteries and more.

Microcontroller Watch (7/9) 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. (7/16) 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.

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Embedded Boards.(6/25) 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. (7/2) 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 (7/9) 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.

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.

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IoT Technology Focus. (6/18) 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.(6/25) 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. (7/2) This newsletter content zeros in on the latest developments in analog and power technologies including DC-DC converters, AC-DC converters, power supplies, op amps, batteries and more.

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.

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Embedded Boards.(5/28) 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. (6/4) 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 (6/11) 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.

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.

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

IoT Technology Focus. (5/21) 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.(5/28) 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. (6/4) 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.

Digital Signage Technologies Gain Momentum

System Solutions

Digital signage ranks among the most dynamic areas of today’s embedded computing space. Vendors involved in this technology continue to roll out new solutions for developing powerful digital signage implementations.

By Jeff Child, Editor-in-Chief

Digital signage is one of those technologies that seemed to breeze into our modern society so quickly and smoothly that it’s hard to image life without it. Today’s technologies provide users with the ability to easily update information on large, high-resolution displays in real-time and in rugged, outdoor environments. And the ability to rotate ads even on billboard-sized displays has multiplied revenue streams for stakeholders using digital signage systems.

At the heart of today’s landscape of modern digital signage are a variety of digital signage players that support advances graphics and multiple streams of connectivity. Also in the mix are general-purpose box-level embedded computing systems that provide solutions for signage applications. Obviously displays make up part of the ecosystem too, but this article focuses strictly on the embedded computing side of digital signage.

Waterproof Design

In March, Ibase Technology launched its latest SW-101-N waterproof digital signage player designed for both indoor and harsh outdoor environments. This rugged fanless signage player is integrated with a 1.91 GHz Intel Atom Processor E3845 Quad-Core Processor and Intel HD graphics (Gen 7-LP) 4EU (Figure 1). The SW-101-N is built to withstand dust, water and extreme temperatures. This ensures the system’s stable operation and reliability in harsh industrial environments.

Figure 1
The SW-101-N is a waterproof, fanless signage player that is integrated with a 1.91 GHz Intel Atom Processor E3845 Quad-Core Processor and Intel HD graphics (Gen 7-LP) 4EU. The SW-101-N is built to withstand dust, water and extreme temperatures in mind.

The SW-101-N meets IP68 standards, allowing it to handle submersion in water for up to 30 minutes at a depth of 1.5 meters. The black-color waterproof enclosure uses a C3 HDMI connector and M12 I/O interface connectors for two USB 2.0, one Gbit LAN, one RS-232, DC power input and digital I/O. Two antenna N-jack type connectors have waterproof designs as well. Aside from being fanless, the unit has a wide operating temperature range of -40°C to 75°C.

The SW-101-N supports Ibase’s iControl and Observer technologies for intelligent control and remote monitoring functions that feature auto power on/off scheduling, power resume, system temperature/voltage remote monitoring and low temperature boot protection. The standard model has 4 GB of DDR3L-1333 system memory, 64 GB mSATA storage, and 12 V DC-in support. Additional features include a watchdog timer, wall mounting and Mini PCIe expansion for optional wireless modules.

Tiny Signage Player

A powerful set of digital signage functionality can be squeezed into a very small form factor these days. In an example along those lines, in September Advantech introduced its USM-110, an ultra-compact digital signage player. This fanless system provides support for Android 6.0 and Advantech’s own WISE-PaaS/SignageCMS digital signage management software. The compact (156 mm x 110 m x 27 mm) device follows earlier Advantech signage computers such as the slim-height, Intel Skylake based DS-081.

The USM-110, which is also available in a less feature rich USM-110 Delight model, ships with 2 GB DDR3L-1333, as well as a microSD slot. It has 16 GB of eMMC on the standard version and 8 GB on the Delight. There’s also a GbE port and an M.2 slot with support for an optional Wi-Fi module with antenna kit.

The USM-110 has two HDMI ports, both with locking ports: an HDMI 2.0 port with H.265-encoded, native 4K at 60 Hz (3840 x 2160) and a 1.4 port with 1080p resolution. The system enables dual simultaneous HD displays. The Delight version lacks the 4K-ready HDMI port, as well as the standard model’s mini-PCIe slot, which is available with an optional 4G module with antenna kit. The Delight is also missing the standard version’s RS232/485/422 port, and it has only one USB 2.0 host port instead of four. Otherwise, the two models are the same, with a micro-USB OTG port, audio jack, reset, dual LEDs and a 12V/3A DC input. The 0.43 kg system has a 0 to 40°C range, and offers VESA, wall, desktop, pole, magnet and DIN-rail mounting (Figure 2).

Figure 2
The USM-110 is a digital signage player that supports Android 6.0 and Advantech’s WISE-PaaS/SignageCMS digital signage management software. The compact unit measures 156 mm x 110 m x 27 mm and features VESA, wall, desktop, pole, magnet and DIN-rail mounting options as shown here.

Advantech’s WISE-PaaS/SignageCMS digital signage management software— also referred to as UShop+ SignageCMS— supports remote, real-time management. It allows users to layout, schedule and dispatch signage contents to the player over the Internet, enabling remote delivery of media and media content switching via interactive APIs. A WISE Agent framework for data acquisition supports RESTful API web services for accessing and controlling applications.

Cable-Free Design

Like many of today’s embedded applications, digital signage has entered the wireless era. Along just those lines, in February Axiomtek launched the DSP300-318, an Intel Apollo Lake based digital signage player promoted for its ultra-slim, 200 mm x 137.8 mm x 20 mm dimensions. The 4K-ready system is designed for space-constrained digital menu boards, self-ordering systems, retail applications, queuing systems, interactive kiosks and video walls.

The system runs Ubuntu or Debian Linux or Windows 10 IoT on Intel’s dual-core, 1.1 GHz Celeron N3350 or quad-core, 2.5 GHz Pentium N4200. Two DDR3L-1600 SO-DIMMs provide up to 8 GB of system memory. And there’s an option for 64 GB eMMC 5.0. The DSP300-318 stands out with its triple M.2 slot design. In addition to an M.2 M-Key 2280 for storage, there’s an M.2 E-Key 2230 for Wi-Fi and Bluetooth and an M.2 B-Key 3042 for 4G LTE. A SIM card slot and 4x antenna mounts are also available (Figure 3).

Figure 3
DSP300-318 is an Intel Apollo Lake based digital signage player with two DDR3L-1600 SO-DIMMs providing up to 8 GB of system memory. There’s an M.2 E-Key 2230 for Wi-Fi and Bluetooth and an M.2 B-Key 3042 for 4G LTE. A SIM card slot and 4x antenna mounts are also available.

The DSP300-318’s 4K-ready HDMI 1.4 and DisplayPort 1.2 ports support dual simultaneous displays. Other features include 2x GbE ports, 3x USB 3.0 ports and single USB 2.0 and RS-232 ports. Dual audio jacks are also available. The DSP300-318 has a 12 VDC terminal screw input, as well as power, reset, and remote switches. There’s also a watchdog timer and a Lithium 3V/220mA-hour battery. The fanless system supports 0 to 50°C temperatures and offers humidity resistance and 3 Grms vibration resistance with M.2 storage (5 to 500 Hz, X, Y, Z).

Players with OPS Support

In 2010, Intel launched the Open Pluggable Specification (OPS) to standardize the system architecture between displays and media players. According to Intel, OPS allows for more cost-effective design, deployment, and management of digital signage and other display solutions that support advanced functionality and emerging use cases, including interactivity and anonymous audience analytics. OPS began appearing in signage systems such as the Axiomtek OPS860 back in 2011. The spec standardizes mounting and power requirements and connects to OPS-compatible displays via an 80-pin JAE Electronics TX24/TX25 blind mate plug and receptacle connector system.

In June 2018, Ibase launched its IOPS- 602 signage player that runs Windows 10 or Ubuntu Linux on Intel’s 6th or 7th Gen. Core QC/DC processors, with a default to dual-core, 7th Gen “Kaby Lake” U-series processors with 15 W TDPs. The standard SKU is a Core i7- 7600U (2.8 GHz/3.9 GHz) with 8 GB RAM and 128 GB of M.2 storage.

The 200 mm x 119 mm x 30 mm IOPS-602 uses an OPS standard 12 V to 19 V DC input and OPS mounting bracket. The JAE connector is mounted on the back of the system. An optional expansion dock with 150 W adapter is available for using the systems with non-OPS displays. Up to 32 GB of DDR4-2133 DRAM can be loaded via dual slots, and there’s an M.2 M-Key slot for 2280 SSD cards. An M.2 E-Key slot is available for 2230-based Wi-Fi/Bluetooth cards.

The IOPS-602 also provides 4x USB 3.0, HDMI 1.4b and Gbit Ethernet ports, as well as an RS232 serial connection provided via an RJ45 port. You also get dual audio jacks, LEDs, a watchdog and iAMT compliance for remote management. The system supports 0°C to 45°C temperatures and resists vibrations to the tune of 5 Grms, 5 to 500 Hz random operation with an SSD.

Moving on to OPS+

Intel developed a follow-on spec called OPS+ that builds on the benefits and powerful functionality of the OPS by enabling a broader range of Intel processors to include the Intel Xeon processor family, a range of Intel desktop processors and Intel FPGAs. OPS+ can also add functionality based on specific industry needs such as supporting simultaneous display and broadcast usages, support for 8K resolution displays and the ability to drive three individual 4K resolution display outputs.

According to Intel, OPS+ defines a 180 mm x 119 mm x 30 mm, fully enclosed digital signage systems with enhanced thermal design supports broader range of Intel processors. The enhanced spec is optimized for interactive white boards (IWBs), commercial digital signage, kiosks, visual data devices, video walls and so on. With OPS+, you can customize a protocol and simultaneously support advanced use cases including real-time analytics and video capture performed on the display itself. The spec also features a second high-speed connector and is backward compatible with previous OPS specifications.

In December Axiomtek released the first OPS+-compliant digital signage player, the OPS700-520. The system is powered by the LGA1151 socket 8th generation Intel Core i7/i5/i3 and Celeron processors (codename: Coffee Lake S) with the Intel Q370 chipset. The player supports Intel Active Management Technology (Intel AMT) 11.0 as well as Intel Unite solution for content sharing and collaboration. It comes with two 260-pin DDR4-2400 SO-DIMM sockets that can provide system memory of up to 32 GB (Figure 4).

Figure 4
The first OPS+-compliant digital signage player, the OPS700-520 is powered by the LGA1151 socket 8th generation Intel Core i7/i5/i3 and Celeron processors. The player supports Intel Active Management Technology (Intel AMT) 11.0 as well as Intel Unite solution for content sharing and collaboration.

The OPS700-520 is compatible with Intel Unite, which allows users to connect and interact with meeting content in real time, thus enhancing seamless meeting experiences and convenience. It also comes with Intel AMT 11.0. Software issues can be repaired wirelessly while failed hardware components can be identified beforehand, thereby lowering maintenance costs and improving efficiency. The signage module is suitable for multi-display solutions such as IWBs in meeting rooms, commercial digital signage, video walls and more.

The digital signage player can be easily connected to an OPS-plus compliant display via two high-speed transmission connector interfaces: JAE TX25A and HRS-FX18. The JAE plug connector interface supports one DisplayPort (4K at 60 Hz), one HDMI 2.0 (4K at 60 Hz), one USB 3.0, two USB 2.0, one audio and UART signals. The HRS plug connector interface supports one DisplayPort (4K at 60 Hz) and one PCI Express x4. These two connector interfaces enhance multimedia performance to meet various requirements. The OPS700-520 also has one PCIe or SATA interface for storage, one M.2 Key E for Wi-Fi modules and one M.2 Key M NVMe SSD slot.

The OPS700-520 maintains the small form factor with dimensions of just 200 mm x 119 mm x 30 mm. It comes with rich I/O connectors including two USB 3.1 Gen2, two USB 2.0, one RS-232 (COM 2), one Gbit LAN with Intel i219-LM Ethernet controller and one HDMI. The unit supports Windows 10 64-bit and Linux operation systems. Also, it supports the TPM 2.0 which can provide security and privacy benefits.

3D Digital Signage

A unique twist on tradition digital signage in the emergence of 3D capability. Feeding that need, in October last year EFCO introduced a development and signage solution for creating advanced 3D slot machine games. The company’s 3D Bare-Eye Content Development Kit and Signage Solution was designed to enable developers of casino slot machine games and digital signage displays to provide 3D content that can be viewed without special glasses (Figure 5).

Figure 5
3D Bare-Eye Content Development Kit and Signage Solution was designed to enable developers of casino slot machine games and digital signage displays to provide 3D content that can be viewed without special glasses.

3D Bare-Eye is based on the Unity software environment, which, according to EFCO, is the defacto standard development toolset among game developers. When used for casino games, instead of simply displaying images of coins on the screen, the coins now appear to be falling out of the slot machine toward the player. But the technology can also be used for any digital signage or progressive display application, says EFCO.

The 3D Bare-Eye Solution is made up of a development kit and a broadcast kit. The content development kit is based on Unity. Because Unity is the most common gaming development environment, it’s easy to adopt. The kit also comes with a monitor, computer system and a proprietary interface card that connects the development system to the playback system. Features of the 3D Content Development kit include: Intel Core i5-6500, 4C/4T with boost to 3.6 GHz, NVIDIA GTX1050Ti (4 GB GDDR5) or GTX1070Ti, 2.5″ SATA SSD 256 GB, an average 190 W power consumption and 3840 x 2160 display support.

The broadcast kit comes with a ready-to-use 55″ and 65″ 3D digital signage 4K display with playback system. A 3D film on the monitor provides the third dimension to viewers. Features of the kit include Intel Pentium CPU, NVIDIA graphics GTX1050Ti (4GB GDDR5), 2.5″ SATA SSD 64 GB storage, power input of AC 100 V to 240 V, 50 Hz to 60 Hz and power consumption averaging 150 W.

Fanless Solution

While dedicated, purpose-built solutions—like the ones discussed so far in this article—are one approach to digital signage applications, another angle is to employ box-level general purpose embedded computers to serve the player functionality. This approach makes sense especially when extreme environmental conditions are an issue. An example along these lines is Logic Supply’s ML100G-31 embedded PC system introduced last August. This system is built around an Intel Dawson Canyon NUC board and employs the company’s Hardshell Fanless Technology to ensure thermal performance. Logic Supply says it’s the smallest fanless and ventless NUC to feature an 8th generation (Kaby Lake) Intel Core i7 processor (Figure 6).

Figure 6
The ML100G-31 embedded PC system is built around an Intel Dawson Canyon NUC board and employs the company’s Hardshell Fanless Technology to ensure thermal performance.

The ML100G-31 provides a fully solid state, passively cooled computing solution, designed for reliability in demanding environments and measures just 142 mm x 62 mm x 107mm. Logic Supply engineers, with support from Intel’s thermal design lab, created a proprietary heatsink for the NUC717DNBE motherboard and Quad-Core i7-8650U Kaby Lake CPU. They also collaborated with Intel to identify a way to ensure that the ML100G-31 features the 5-year lifecycle that will allow their industrial computing clients to standardize on the platform.

The ML100 is able to cool the processor and other internal components by employing Logic Supply’s proven Hardshell Fanless Technology. Through the use of unique exterior fins and specially machined heatsink design, the system is able to maintain an optimal operating temperature without the need for a cooling fan. Removing the fan from the system improves overall reliability. Unlike fanned solutions that are vulnerable to airborne contaminants, this fanless design is able to operate in challenging computing environments across a range of industries including manufacturing and automation, industrial digital signage and others.

The system can be configured with up to 32 GB of memory and 1 TB of M.2 storage. Connectivity includes four USB 3.0 ports, two HDMI ports supporting dual 4K output, Gbit LAN and an optional COM port for legacy equipment connectivity. Operating system options include both Windows and Linux Ubuntu.

System Based on Mini-ITX

In another example of a general-purpose system that’s suited for digital signage, AAEON in September released the ACS-1U01 Series, a range of turnkey solutions that embed three of its bestselling SBCs. By enclosing the boards inside a tough 1U chassis, the unit provides a ready-to-go system for use in a variety of applications including digital signage as well as industrial automation, POS, medical equipment and transportation.

The three models—the ACS-1U01-BT4 (Figure 7), ACS-1U01-H110B, and ACS-1U01-H81B—feature a tough, 44.45 mm-high chassis with a wall mount kit and 2.5″ HDD tray. The low-profile, low-power-consumption systems have full Windows and Linux support, they can be expanded via full- and half-size Mini-Card slots and heatsinks give them operating temperature ranges of 0°C to 50°C.

Figure 7
The ACS-1U01-BT4 houses AAEON’s EMB-BT4 motherboard, which can be fitted with either an Intel Atom J1900 or N2807 processor. The J1900 can be used with a pair of DDR3L SODIMM sockets for up to 8 GB dual-channel memory, while the N2807 can be used with a single DDR3L SODIMM socket.

The ACS-1U01-BT4 houses AAEON’s EMB- BT4 motherboard, which can be fitted with either an Intel Atom J1900 or N2807 processor. The J1900 can be used with a pair of DDR3L SODIMM sockets for up to 8 GB dual-channel memory, while the N2807 can be used with a single DDR3L SODIMM socket. The board’s extensive I/O interface provides the system with a GbE LAN port, dual independent HDMI and VGA displays, a USB3.0 port, up to seven USB 2.0 and up to six COM ports.

The ACS-1U01-H110B contains AAEON’s EMB-H110B, which is built to accommodate up to 65 W 6th/7th Generation Intel Core i Series socket-type processors and supports up to 32 GB dual-channel memory via a pair of DDR4 SODIMM sockets. Dual independent display support is possible through two HDMI ports, or the option of DP connections. The system also features a GbE LAN port, four USB 3.0 ports, four USB 2.0 ports and a COM port.

The ACS-1U01-H81B is built around AAEON’s EMB-H81B, which is designed for 4th Generation Intel Core i Series socket-type processors with TDPs of up to 65 W. Two SODIMM sockets allow for up to 16 GB dual-channel DDR3 memory, and HDMI, DisplayPort and optional VGA ports enable dual independent display. The system has two GbE LAN ports, two USB3.0 ports and six USB 2.0 ports.

There’s no doubt that digital signage is an application that puts high demands on a variety of technology segments—from graphics processing to connectivity to form factor design. To keep pace with demands, makers of digital signage players and embedded PCs continue to innovate by adding more capabilities while also shrinking size, weight and power.

RESOURCES

AAEON | www.aaeon.com
Advantech | www.advantech.com
Axiomtek | us.axiomtek.com
EFCO | www.efcotec.com
Ibase Technology | www.ibase.com.tw
Intel | www.intel.com
Logic Supply | www.logicsupply.com

This article appeared in the May 346 issue of Circuit Cellar

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Capacitive vs. Inductive Sensing

Touch Trade-Offs

Touch sensing has become an indispensable technology across a wide range of embedded systems. In this article, Nishant discusses capacitive sensing and inductive sensing, each in the context of their use in embedded applications. He then explores the trade-offs between the two technologies, and why inductive sensing is preferred over capacitive sensing in some use cases.

By Nishant Mittal

Touch sensing was first implemented using resistive sensing technology. But resistive sensing had a number of disadvantages, including low sensitivity, false triggering and shorter operating life. All of that discouraged its use and led to its eventual downfall in the market.

Today whenever people talk about touch sensing, they’re usually referring to capacitive sensing. Capacitive sensing has proven to be robust not only in a normal environmental use cases but also underwater, thanks to its water-resistant capabilities. As with any technology, capacitive sensing comes with a new set of disadvantages. These disadvantages tend to more application-specific. That situation opened the door for the advent of inductive sensing technology.

In this article, we’ll discuss capacitive sensing for embedded applications and how it can be used in various applications. We will then explore the use of inductive sensing in embedded products and why inductive sensing is preferred over capacitive sensing in some use cases. Finally, we’ll compare the advantages of inductive sensing over capacitive sensing in these applications.

Capacitive Sensing for Embedded

Capacitive sensing operates on the principle of monitoring the change in parasitic capacitance due to a finger touch (Figure 1). Capacitive sensing has been used primarily in two different forms: self-capacitance and mutual-capacitance. In self-capacitance mode, the net capacitance due to a finger touch and board capacitance is additive. This capacitance includes PCB traces and PCB materials like FR4, which has more capacitance compared to Flex materials and many similar dielectrics. Self-capacitance mode is useful in general touch application like buttons for touch-and-respond applications. In contrast, mutual capacitance is well-suited for applications involving more complex sensing such as gestures, multi-touch and sliders.

FIGURE 1
Capacitive sensing technique

Mutual capacitance sensing uses two different lines: TX(Transmitter) and RX(Receiver). The Transmitter sends a PWM signal with respect to the system VDD and GND. The Receiver detects the amount of charge received on the RX electrode.

One of the difficult use cases of capacitive sensing is that it cannot operate perfectly underwater. It also requires relatively strict design guidelines to be followed for error-free operation. Capacitive sensing performance is also impacted by nearby LEDs and power lines on PCBs. Implementing auto-tuning with variation in trace capacitance, variation in capacitive sensing buttons and different slider sizes and shapes all require different designs. Implementation challenges in industrial applications include using capacitive sensing with thicker glass material (display glass) and meeting capacitive sensor sensitivity requirements with those types of materials.

Inductive Sensing for Embedded

Inductive sensing enables the next-generation of touch technology in applications involving metal-over-touch use cases such as in automotive, industrial and many embedded and IoT applications. Inductive sensing is based on the principle of electromagnetic coupling, between a coil and the target (Figure 2). When a metal target comes closer to the coil, its magnetic field is obstructed and it passes through the metal target before coupling to its origin. This phenomenon causes some energy to get transferred to the metal target—referred to as eddy current—that causes a circular magnetic field. Eddy current induces a reverse magnetic field, in turn leading to a reduction in inductance.

FIGURE 2
Inductive sensing technique [1]

To cause the resonant frequency to occur, a capacitor is added in parallel to the coil to cause the LC tank circuit. As the inductance starts reducing, the frequency shifts upward changing the amplitude throughout. In contrast to a capacitive sensor, inductive sensing is able to operate reliably in the presence of water thanks to the removal of a dielectric from the sensor. This advantage brings inductive sensing touch sensing to a wide range of applications that involve liquids such as underwater equipment, flow meters, RPM detection, medical instruments and many others. Inductive sensing also supports biomedical applications. In general applications, inductive sensing enables replacement of mechanical switches and proximity sensing of metal objects. For example, in automotive applications, inductive sensing can be used to replace mechanical handles as well as detect car proximity. Some of these examples will be discussed in detail later..

Read the full article in the May 346 issue of Circuit Cellar
(Full article word count: 1842 words; Figure count: 6 Figures.)

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Next Newsletter: Automotive Electronics

Coming to your inbox tomorrow: Circuit Cellar’s Automotive Electronics newsletter. April has a 5th Tuesday, so we’re bringing you a bonus newsletter:
Automotive Electronics. Automotive dashboard are evolving into so-called infotainment systems at the same time more of the car is being controlled by embedded  computing. That’s driving a need for powerful MCU-based solutions that support these trends. This newsletter looks at the latest technology trends and product developments in automotive electronics.

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Analog & Power. (5/7) 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 (5/14) 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. (5/21) 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.(5/28) 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.

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.

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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:

April has a 5th Tuesday, so we’re bringing you a bonus newsletter:
Automotive Electronics (4/30)  Automotive dashboard are evolving into so-called infotainment systems at the same time more of the car is being controlled by embedded  computing. That’s driving a need for powerful MCU-based solutions that support these trends. This newsletter looks at the latest technology trends and product developments in automotive electronics.

Analog & Power. (5/7) 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 (5/14) 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. (5/21) 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.

May Circuit Cellar: Sneak Preview

The May issue of Circuit Cellar magazine is out next week!. We’ve been hard at work laying the foundation and nailing the beams together with a sturdy selection of  embedded electronics articles just for you. We’ll soon be inviting you inside this 84-page magazine.

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

 

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

EMBEDDED COMPUTING AT WORK

Technologies for Digital Signage
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. Circuit Cellar Chief Editor Jeff Child looks at the latest technology trends and product developments in digital signage.

PC/104 and PC/104 Family Boards
PC/104 has come a long way since its inception over 25 ago. With its roots in ISA-bus PC technology, PC/104 evolved through the era of PCI and PCI Express by spinning off its wider family of follow on versions including PC/104-Plus, PCI-104, PCIe/104 and PCI/104-Express. This Product Focus section updates readers on these technology trends and provides a product gallery of representative PC/104 and PC/104-family boards.

TOOLS & TECHNIQUES FOR EMBEDDED ENGINEERING

Code Analysis Tools
Today it’s not uncommon for embedded devices to have millions of lines of software code. Code analysis 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 code analysis tools.

Transistor Basics
In this day and age of highly integrated ICs, what is the relevance of the lone, discrete transistor? It’s true that most embedded systems can be solved by chip level solutions. But electronic component vendors do still make and sell individual transistors because there’s still a market for them. In this article, Stuart Ball reviews some important basics about transistors and how you can use them in your embedded system design.

Pressure Sensors
Over the years, George Novacek has done articles examining numerous types of sensors that measure various physical aspects of our world. But one measurement type he’s not yet discussed in the past is pressure. Here, George looks at pressure sensors in the context of using them in an electronic monitoring or control system. The story looks at the math, physics and technology associated with pressure sensors.

MICROCONTROLLERS DO IT ALL

Robotic Arm Plays Beer Pong
Simulating human body motion is a key concept in robotics development. With that in mind, learn how these Cornell graduates Daniel Fayad, Justin Choi and Harrison Hyundong Chang accurately simulate the movement of a human arm on a small-sized robotic arm. The Microchip PIC32 MCU-based system enables the motion-controlled, 3-DoF robotic arm to take a user’s throwing motion as a reference to its own throw. In this way, they created a robotic arm that can throw a ping pong ball and thus play beer pong.

Fancy Filtering with the Teensy 3.6
Signal filtering entails some tricky tradeoffs. A fast MCU that provides hardware-based floating-point capability eases some of those tradeoffs. In the past, Brian Millier has used the Arm-based Teensy MCU modules to serve meet those needs. In this article, Brian taps the Teensy 3.6 Arm MCU module to perform real-time audio FFT-convolution filtering.

Real-Time Stock Monitoring Using an MCU
With today’s technology, even very simple microcontroller-based devices can fetch and display data from the Internet. Learn how Cornell graduates David Valley and Saelig Khatta built a system using that can track stock prices in real-time and display them conveniently on an LCD screen. For the design, they used an Espressif Systems ESP8266 Wi-Fi module controlled by a Microchip PIC32 MCU. Our fun little device fetches chosen stock prices in real-time and displays them on a screen.

… AND MORE FROM OUR EXPERT COLUMNISTS

Attacking USB Gear with EMFI
Many products use USB, but have you ever considered there may be a critical security vulnerability lurking in your USB stack? In this article, Colin O’Flynn walks you through on example product that could be broken using electromagnetic fault injection (EMFI) to perform this attack without even removing the device enclosure.

An Itty Bitty Education
There’s no doubt that we’re living in a golden age when it comes to easily available and affordable development kits for fun and education. With that in mind, Jeff Bachiochi shares his experiences programming and playing with the Itty Bitty Buggy from Microduino. Using the product, you can build combine LEGO-compatible building blocks into mobile robots controlled via Bluetooth using your cellphone.

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.(4/23) 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.

April has a 5th Tuesday, so we’re bringing you a bonus newsletter:
Automotive Electronics (4/30)  Automotive dashboard are evolving into so-called infotainment systems at the same time more of the car is being controlled by embedded  computing. That’s driving a need for powerful MCU-based solutions that support these trends. This newsletter looks at the latest technology trends and product developments in automotive electronics.

Analog & Power. (5/7) 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 (5/14) 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.

Capacitive Touch-Key MCUs Enable 2D/3D Gesture Control

Renesas Electronics has introduced two touch-free user interface (UI) solutions for simplifying the design of 2D and 3D control-based applications. Based on Renesas’ capacitive sensor microcontrollers, the new solutions support the development of UI that allows users to operate home appliances, as well as industrial and OA equipment without touching the devices. The UI solutions make it possible for appliance and equipment manufacturers to quickly develop touch-free interfaces that increase the added-value of their products in terms of both equipment convenience and design.
There are a variety of situations where touch-free operation is advantageous, such as when the users’ hands are wet, when the controls are out of reach, or when it is not safe for the user to touch the controls. Renesas new touch-free UI, for example in the kitchen, users could adjust water temperature and flow rate through hand gestures near the faucets or adjust stove fan operation by holding a hand over the hood. The touch-free UI solutions allow customers to easily implement these interfaces in their embedded equipment. The reference designs are available for download.

The new gesture solutions detect motion in a 2D coordinate system and in 3D space, respectively. With both solutions, Renesas provides design materials (circuit diagrams, board design data files and parts lists) that form the reference hardware for the capacitive touch-key MCU, as well as coordinate calculation middleware, sample programs, application notes and an evaluation tool for monitoring the detected coordinates. The touch-free UI solutions have passed class B testing for the IEC 61000 4-3 level 3 and 4-6 level 3 noise immunity standards, and can achieve stable operation.

The 3D gesture solution is available in three different sizes and can be selected based on the application:

  • Standard version (160 × 160 × 100 mm) with RX231 MCU
  • Miniature version (80 × 80 × 80 mm) with RX130 MCU
  • Slim version (100 × 100 × 20 mm) with RX130 MCU for additional space saving

Renesas Electronics | www.renesas.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. (4/16) 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.(4/23) 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.

April has a 5th Tuesday, so we’re bringing you a bonus newsletter:
Automotive Electronics (4/30)  Automotive dashboard are evolving into so-called infotainment systems at the same time more of the car is being controlled by embedded  computing. That’s driving a need for powerful MCU-based solutions that support these trends. This newsletter looks at the latest technology trends and product developments in automotive electronics.

Analog & Power. (5/7) 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.

IoT Monitoring System for Commercial Fridges

Using LoRa Technology

IoT implementations can take many shapes and forms. Learn how these four Camosun College students developed a system to monitor all the refrigeration units in a commercial kitchen simultaneously. The system uses Microchip PIC MCU-based monitoring units and wireless communication leveraging the LoRa wireless protocol.

By Tyler Canton, Akio Yasu, Trevor Ford and Luke Vinden

In 2017, the commercial food service industry created an estimated 14.6 million wet tons of food in the United States [1]. The second leading cause of food waste in commercial food service, next to overproduction, is product loss due to defects in product quality and/or equipment failure [2].

While one of our team members was working as the chef of a hotel in Vancouver, more than once he’d arrive at work to find that the hotel’s refrigeration equipment had failed overnight or over the weekend, and that thousands of dollars of food had become unusable due to being stored at unsafe temperatures. He always saw this as an unnecessary loss—especially because the establishment had multiple refrigeration units and ample space to move product around. In this IoT age, this is clearly a preventable problem.

For our Electronics & Computer Engineering Technologist Capstone project, we set forth to design a commercial refrigeration monitoring system that would concurrently monitor all the units in an establishment, and alert the chefs or managers when their product was not being stored safely. This system would also allow the chef to check in on his/her product at any time for peace of mind (Figure 1).

Figure 1
This was the first picture we took of our finished project assembled. This SLA printed enclosure houses our 10.1″ LCD screen, a Raspberry Pi Model 3B and custom designed PCB.

We began with some simple range testing using RFM95W LoRa modules from RF Solutions, to see if we could reliably transmit data from inside a steel box (a refrigerator), up several flights of stairs, through concrete walls, with electrical noise and the most disruptive interference: hollering chefs. It is common for commercial kitchens to feel like a cellular blackout zone, so reliable communication would be essential to our system’s success.

System Overview

We designed our main unit to be powered and controlled by a Raspberry Pi 3B (RPi) board. The RPi communicates with an RFM95W LoRa transceiver using Serial Peripheral Interface (SPI). This unit receives temperature data from our satellite units, and displays the temperatures on a 10.1″ LCD screen from Waveshare. A block diagram of the system is shown in Figure 2. We decided to go with Node-RED flow-based programming tool to design our GUI. This main unit is also responsible for logging the data online to a Google Form. We also used Node-RED’s “email” nodes to alert the users when their product is stored at unsafe temperatures. In the future, we plan to design an app that can notify the user via push notifications. This is not the ideal system for the type of user that at any time has 1,000+ emails in their inbox, but for our target user who won’t allow more than 3 or 4 to pile up it has worked fine.

Figure 2
The main unit can receive temperature data from as many satellite units as required. Data are stored locally on the Raspberry Pi 3B, displayed using a GUI designed by Node-RED and logged online via Google Sheets.

We designed an individual prototype (Figure 3) for each satellite monitoring unit, to measure the equipment’s temperature and periodically transmit the data to a centralized main unit through LoRa communication. The units were intended to operate at least a year on a single battery charge. These satellites, controlled by a Microchip Technology PIC24FJ64GA704 microcontroller (MCU), were designed with an internal Maxim Integrated DS18B20 digital sensor (TO-92 package) and an optional external Maxim

Figure 3
This enclosure houses the electronics responsible for monitoring the temperatures and transmitting to the main unit. These were 3D printed on Ultimaker 3 printers.

Integrated DS18B20 (waterproof stainless steel tube package) to measure the temperature using the serial 1-Wire interface.

Hardware

All our boards were designed using Altium Designer 2017 and manufactured by JLCPCB. We highly recommend JLCPCB for PCB manufacturing. On a Tuesday we submitted our order to the website, and the finished PCB’s were manufactured, shipped, and delivered within a week. We were amazed by the turnaround time and the quality of the boards we received for the price ($2 USD / 10 PCB).

Figure 4
The main unit PCB’s role is simply to allow the devices to communicate with each other. This includes the RFM95W LoRa transceivers, RPi, LCD screen and a small fan

Main Unit Hardware: As shown in Figure 4, our main board’s purpose is communicating with the RPi and the LCD. We first had to select an LCD display for the main unit. This was an important decision, as it was the primary human interface device (HID) between the system and its user. We wanted a display that was around 10″—a good compromise between physical size and readability. Shortly after beginning our search, we learned that displays between 7″ and 19″ are not only significantly more difficult to come by, but also significantly more expensive. Thankfully, we managed to source a 10.1″ display that met our budget from robotshop.com. On the back of the display was a set of female header pins designed to interface with the first 26 pins of the RPi’s GPIO pins. The only problem with the display was that we needed access to those same GPIO pins to interface with the rest of our peripherals.

Figure 5
Our main board, labeled Mr. Therm, was designed to attach directly to the LCD screen headers. RPi pins 1-26 share the same connectivity as the main board and the LCD.

We initially planned on fixing this problem by placing our circuit board between the RPi and the display, creating a three-board-stack. Upon delivery and initial inspection of the display, however, we noticed an undocumented footprint that was connected to all the same nets directly beneath the female headers. We quickly decided to abandon the idea of the three-board-stack and decided instead to connect our main board to that unused footprint in the same way the RPi connects to display (Figure 5). This enabled us to interface all three boards, while maintaining a relatively thin profile. The main board connects four separate components to the rest of the circuit. It connects the RFM95W transceiver to the RPi, front panel buttons, power supply and a small fan.

Read the full article in the April 345 issue of Circuit Cellar
(Full article word count: 3378 words; Figure count: 11 Figures.)

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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.

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. (4/2) 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 (4/9) 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. (4/16) 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.