Sensor Interface IC Enables Advanced Bio-Chemical Sensing

Analog Devices has announced today a new sensor interface IC that enables the next generation of intelligent electrochemical sensors. According to the company, it is the only solution available to incorporate potentiostat and Electrochemical Impedance Spectroscopy (EIS) functionality on a single chip. The ADuCM355 precision analog microcontroller with bio-sensor and chemical sensor interface is well suited for applications such as industrial gas sensing, instrumentation, vital signs monitoring and disease management.

The ADuCM355 is an ultra-low power precision analog microcontroller based on the ARM Cortex M3 processor especially designed to control and measure chemical and biosensors. It is the only solution available that supports dual potentiostat and >3 sensor electrodes.

Additional features:

  • Voltage, current and impedance measurement
  • Dual ultra-low power, low noise potentiostats: 8.5u A, 1.6 uV RMS
  • Flexible 16-bit, 400 ksps measurement channel
  • Advanced sensor diagnostics
  • Integrated analog hardware accelerators
  • 26 MHz core, 128 kB Flash, 64 kB SRAM

View the ADuCM355 product page, download data sheet, order samples and evaluation board.: www.analog.com/ADuCM355. Available now, the ADuCM355 is priced at $5.90 (1,000s).

Analog Devices | www.analog.com

MCUs Offer Configurable Signal Chain Elements

Texas Instruments (TI) has announced the addition of new microcontrollers with integrated signal-chain elements and an extended operating temperature range to its MSP430 value line portfolio. New MSP430FR2355 ferroelectric random access memory (FRAM) MCUs allow developers to reduce printed circuit board (PCB) size and bill-of-materials (BOM) cost while meeting temperature requirements for sensing and measurement in applications such as smoke detectors, sensor transmitters and circuit breakers.
Engineers can enjoy more flexibility in their system design with MSP430FR2355 MCUs, which integrate smart analog combos—configurable signal-chain elements that include options for multiple 12-bit digital-to-analog converters (DACs) and programmable gain amplifiers, along with a 12-bit analog-to-digital converter (ADC) and two enhanced comparators.

Developers can use MSP430FR2355 MCUs for applications that require operation at temperatures as high as 105°C while also benefiting from FRAM data-logging capabilities. Engineers gain more options to select the right memory and processing speed for cost-sensitive applications with the MSP430FR2355 MCUs, which add options to the MSP430 value line FRAM MCU family by offering memory up to 32 KB and central processing unit (CPU) speeds up to 24 MHz. Designers can also scale to the rest of the MSP430 FRAM MCU portfolio for applications that require up to 256 KB of memory, higher performance or more analog peripherals.

Developers can start evaluating with the MSP430FR2355 MCU LaunchPad development kit (MSP-EXP430FR2355), available for US$12.99 from the TI store.

Texas Instruments | www.ti.com

PICMG to Demo IIoT Development Concept at Sensors Expo

The PCI Industrial Computer Manufacturers Group (PICMG), a not-for-profit consortium of companies and organizations that collaboratively develop open specifications will have a booth at Sensors Expo (#1642) to promote its concepts for a new IIoT specification.  Live demonstrations will be performed to illustrate PICMG’s approach to connect sensor and the controller endpoints using new Internet of Things (IoT) methodologies.

Doug Sandy, CTO of PICMG, will hold a tutorial on Thursday June 28th in the Live Embedded Theater on the subject “Making Sense of Industrial IoT”.  Part of the PICMG tutorial and booth live demonstrations will be to illustrate RESTful API “put, get, delete” commands for the connected sensor/computer interaction. PICMG has a working agreement with the DMTF to utilize the well-known Redfish APIs. The new PICMG specification will intend to develop a meta-data model that encompasses a breadth of individual data models for IoT. The booth will include information on a concept for a developer’s kit geared to help legacy sensors and PLCs become “IoT enabled”. PICMG will also have details on its existing embedded market open specifications for high-performance industrial computing.

PICMG | www.picmg.org

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:

Analog & Power. (7/3) 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 (7/10) 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. (7/17) 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.

Development Tool Speeds IoT Sensor Design

STMicroelectronics offers a tool called AlgoBuilder designed to take the coding out of firmware development by letting users build sensor-control algorithms graphically with library modules, ready to compile and run on an STM32 microcontroller.

Created to simplify development of IoT devices containing ST’s MEMS sensors and MCUs, AlgoBuilder helps quickly get a proof-of-concept model up and running. Users can build their algorithms quickly and intuitively by dragging and dropping selected functions, connecting the blocks, and configuring properties. AlgoBuilder validates all design rules and automatically generates C code based on the graphical design.
AlgoBuilder provides libraries such as logic and mathematical operators, signal processing, user inputs, vector operations, and many others. Turnkey algorithms for commonly used functions such as sensor hub, motion-sensor calibration, activity recognition, motion intensity, and pedometer are included. Users can also add their own custom functions to the AlgoBuilder libraries.

AlgoBuilder provides an environment for connecting them with other logic to create a complete firmware project ready to compile using an STM32 IDE (Integrated Development Environment) such as TrueSTUDIO for STM32, SW4STM32 System Workbench for STM32, IAR-EWARM IAR Embedded Workbench for Arm and Keil µVision MDK-ARM-STM32.

AlgoBuilder can generate firmware for deployment on various STM32 platforms. These include the NUCLEO-F401RE and NUCLEO-L476RG development boards with the X-NUCLEO-IKS01A2 MEMS-sensor expansion board, and ST’s SensorTile IoT module. The SensorTile integrates a STM32L476JG ultra-low-power MCU, motion and environmental MEMS sensors and Bluetooth Low Energy (BLE) connectivity.

Users can test their firmware by launching the Unicleo-GUI application from within AlgoBuilder, to display outputs from running firmware. Unicleo-GUI is a dedicated sensor graphical user interface for use with ST’s sensor expansion software packages and X-NUCLEO boards, and lets users visualize sensor data as a time plot, scatter plot, or 3D plot.

AlgoBuilder is available now, and free to download from www.st.com/algobuilder-pr

STMicroelectronics | www.st.com

Silicon APDs are Optimized for LIDAR Applications

The Series 9 from First Sensor offers a wide range of silicon avalanche photodiodes (APDs) with very high sensitivity in the near infrared (NIR) wavelength range, especially at 905 nm. With their internal gain mechanism, large dynamic range and fast rise time the APDs are ideal for LIDAR systems for optical distance measurement and object recognition according to the time of flight method. Application examples include driver assistance systems, drones, safety laser scanners, 3D-mapping and robotics.

The Series 9 offers detectors as single elements as well as linear and matrix arrays with multiple sensing elements. The package options include rugged TO housings or flat ceramic SMD packages. The slow increase of the gain of the Series 9 photodiodes with the applied reverse bias voltage allows for easy and precise adjustments of high gain factors. For particularly low light levels, hybrid solutions are also available that further enhance the APD signal with an internal transimpedance amplifier (TIA). The integrated amplifier is optimally matched to the photodiode and allows compact setups as well as very large signal-to-noise ratios.

Using its own semiconductor manufacturing facility and extensive development capabilities, First Sensor can adapt its silicon avalanche photodiodes to specific customer requirements, such as sensitivity, gain, rise time or design.

Important features of the Series 9 APDs:

  • Very high sensitivity at 905 nm
  • Large dynamic range and fast rise time
  • Single element photodiodes as well as linear and matrix arrays
  • Rugged TO housings or flat ceramic SMD packages
  • Hybrid solutions with integrated TIA

First Sensor | www.first-sensor.com

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.

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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:

Embedded Boards.(6/26) 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. (7/3) 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 (7/10) 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.

July Circuit Cellar: Sneak Preview

The July issue of Circuit Cellar magazine is coming soon. And we’ve rustled up a great herd of embedded electronics articles for you to enjoy.

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

 

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

TECHNOLOGIES FOR THE INTERNET-OF-THINGS

Wireless Standards and Solutions for IoT  
One of the critical enabling technologies making the Internet-of-Things possible is the set of well-established wireless standards that allow movement of data to and from low-power edge devices. Here, Circuit Cellar’s Editor-in-Chief, Jeff Child, looks at key wireless standards and solutions playing a role in IoT.

Product Focus: IoT Device Modules
The rapidly growing IoT phenomenon is driving demand for highly integrated modules designed to interface with IoT devices. This Product Focus section updates readers on this technology trend and provides a product album of representative IoT interface modules.

TOOLS AND TECHNIQUES AT THE DESIGN PHASE

EMC Analysis During PCB Layout
If your electronic product design fails EMC compliance testing for its target market, that product can’t be sold. That’s why EMC analysis is such an important step. In his article, Mentor Graphics’ Craig Armenti shows how implementing EMC analysis during the design phase provides an opportunity to avoid failing EMC compliance testing after fabrication.

Extreme Low-Power Design
Wearable consumer devices, IoT sensors and handheld systems are just a few of the applications that strive for extreme low-power consumption. Beyond just battery-driven designs, today’s system developers want no-battery solutions and even energy harvesting. Circuit Cellar’s Editor-in-Chief, Jeff Child, dives into the latest technology trends and product developments in extreme low power.

Op Amp Design Techniques
Op amps can play useful roles in circuit designs linking the real analog world to microcontrollers. Stuart Ball shares techniques for using op amps and related devices like comparators to optimize your designs and improve precision.

Wire Wrapping Revisited
Wire wrapping may seem old fashioned, but this tried and true technology can solve some tricky problems that arise when you try to interconnect different kinds of modules like Arduino, Raspberry Pi and so on. Wolfgang Matthes steps through how to best employ wire wrapping for this purpose and provides application examples.

DEEP DIVES ON MOTOR CONTROL AND MONITORING

BLDC Fan Current
Today’s small fans and blowers depend on brushless DC (BLDC) motor technology for their operation. In this article, Ed Nisley explains how these seemingly simple devices are actually quite complex when you measure them in action. He makes some measurements on the motor inside a tangential blower and explores how the data relates to the basic physics of moving air.

Electronic Speed Control (Part 1)
An Electronic Speed Controller (ESC) is an important device in motor control designs, especially in the world of radio-controlled (RC) model vehicles. In Part 1, Jeff Bachiochi lays the groundwork by discussing the evolution of brushed motors to brushless motors. He then explores in detail the role ESC devices play in RC vehicle motors.

MCU-Based Motor Condition Monitoring
Thanks to advances in microcontrollers and sensors, it’s now possible to electronically monitor aspects of a motor’s condition, like current consumption, pressure and vibration. In this article, Texas Instrument’s Amit Ashara steps through how to best use the resources on an MCU to preform condition monitoring on motors. He looks at the signal chain, connectivity issues and A-D conversion.

AND MORE FROM OUR EXPERT COLUMNISTS

Verifying Code Readout Protection Claims
How do you verify the security of microcontrollers? MCU manufacturers often make big claims, but sometimes it is in your best interest to verify them yourself. In this article, Colin O’Flynn discusses a few threats against code readout and looks at verifying some of those claimed levels.

Thermoelectric Cooling (Part 1)
When his thermoelectric water color died prematurely, George Novacek was curious whether it was a defective unit or a design problem. With that in mind, he decided to create a test chamber using some electronics combined with components salvaged from the water cooler. His tests provide some interesting insights into thermoelectric cooling.

 

Passive Infrared Sensors

Homing in on Heat

One way to make sure that the lights get turned off when you leave a room is to use Passive Infrared (PIR) sensors. Jeff examines the science and technology behind PIR sensors. He then details how to craft effective program code and control electronics to use PIR sensors is a useful way.

By Jeff Bachiochi

“The last one to leave, please turn off the lights.” How many times did you hear this while growing up? It’s an iconic phrase sometimes used to suggest the end of life, but as I remember it, just an effort to save electricity. I would always use the logic that bulbs burn out during the initial surge current and not necessarily from remaining on, but that logic never worked on Mom. To this day I am obsessive about turning lights off (thanks Mom!). To that end I tried installing Passive Infra Red (PIR) sensors to handle this automatically. After being inundated with complaints (from my wife Beverly) about lights turning off “while I’m still in the room,” I gave up.

While PIR devices are sensitive to heat (infrared)—the human body’s radiation is strongest at a wavelength of 9.4 µm—they are based on the heat source moving past the sensor. Let’s look at a typical PIR sensor element to see how this works. The RE200B PIR sensor comes in a TO-5 package. Manufactured by Glolab, this device actually contains two sensors as seen in Figure 1.

FIGURE 1
The metal tab on the TO-5 can indicates the X-axis plane across both sensor elements. The window filter material is optimized for approximately 10 μm wavelength.

Each pyroelectric sensor is made of a crystalline material that generates a surface electric charge when exposed to heat. When the amount of radiation striking the crystal changes, so does amount of charge on the input to a sensitive FET device built into the sensor. The two elements are in series with the FET input connected to their junction. With this configuration and a wide (138-degree) field of view, whatever ambient light falls on both the sensors is canceled out. The sensor elements are sensitive to radiation over a wider range so a filter window is added to the TO-5 package to limit detectable radiation. As a standalone this device is not very useful. We need a way to interrupt the heat source from hitting both sensor elements at the same time.

Anyone familiar with opto encoders already understands how this works. Opto transmitter/receiver pairs are placed on opposite sides of a spoked wheel. Light passes between the spokes as it rotates between the pair. A second pair is placed such that when one light path is blocked by a spoke, the other light path is between spokes. As the spoked wheel rotates, the opto device’s output alternates between one coupled pair and the other. With some logic on the opto outputs, you can tell both direction and speed of the rotation. Creating the same kind of “picket fence” in front of the infrared (IR) sensor elements can cause the radiation to be alternately blocked and passed to each sensor. The trick will be to design the slat width and placement to give the desired effect.

Fresnel Lens

Figure 2
Lenses of large aperture and short
focal length are massive. The bulk
of the material can be eliminated as
long as the lens’ curve stays the same.
This can be accomplished by a series
of annular lens rings or the special grinding pattern on a single blank.

A lens could be used to artificially reduce the field of view, by collecting and focusing it into a smaller spot. Move an object in front of the lens left to right and the spot moves right to left, behind the lens. If the spot passes over the two sensor elements sequentially, voilà—each sensor will produce a push or pull at the center tapped output. And that is something we can detect. A single lens would create one sensitive area out in front of the device. This might be just what you are looking for. However, to be sensitive to a wider range we must have multiple lenses. Since glass is opaque to IR we can’t use a typical glass lens. It turns out that polyethylene type materials do pass IR light and can be formed in various Fresnel lens patterns.

The idea for the Fresnel lens goes back to the French mathematicians of the late 18th century. This was an attempt to make lenses thinner while retaining the optical quality of the original. Figure 2 shows how unnecessary thickness is removed from an original lens without changing the lens’ curvature. In the early 19th century this idea was adapted for use in lighthouses by Augustin-Jean Fresnel. The thin cross section of the Fresnel lens makes it ideal for PIR lenses. …

Read the full article in the June 335 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.

High-Accuracy MEMS Sensors Target Industrial Sensing

STMicroelectronics has announced the release of new high-stability MEMS sensors with 10-year product-longevity assurance. The new sensors, to be made available during 2018, begin with the IIS3DHHC, a 3-axis accelerometer optimized for high measurement resolution and stability to ensure accuracy over time and temperature. The IIS3DHHC targets precision inclinometers in antenna-positioning mechanisms for communication systems, Structural Health Monitoring (SHM) equipment for keeping buildings and bridges safe, and stabilizers or levelers for a wide variety of industrial platforms. Its long-term accuracy and robustness are also ideal for high-sensitivity tilt and security sensors, as well as image stabilization in high-end Digital Still Cameras (DSCs).
ST’s 10-year longevity commitment assures long-term availability of a wide range of high-performing components used in industrial equipment, helping vendors handle the typically long in-market lifetimes of their products and extended operation in challenging environmental conditions. In addition to industrial sensors, the program covers STM32 microcontrollers, motor drivers, analog components, power converters, LEDs, and existing MEMS sensors that will be supported for at least 10 years.

The IIS3DHHC is in production now, in a high-quality 16-lead 5mm x 5mm x 1.7mm ceramic LGA package, priced from $4.50 for orders of 1000 pieces.

STMicroelectronics | www.st.com

Barometric Pressure Sensor Serves Consumer Drone Needs

Bosch Sensortec has introduced a new high performance barometric pressure MEMS sensor: the BMP388 is ideally suited for altitude tracking in Consumer Electronics (CE) drones, wearables, smart homes and other applications. The BMP388 delivers outstanding altitude stabilization in drones, where accurate measurement of barometric pressure provides the essential altitude data for improving flight stability and landing accuracy. The new barometric pressure sensor is part of Bosch Sensortec’s comprehensive sensor solution for drones, which includes the BMI088 Inertial Measurement Unit (IMU) for accurate steering and the BMM150 geomagnetic sensor for the provision of heading data.

The BMI088 is a 6-axis IMU, consisting of a triaxial 16-bit acceleration sensor with excellent performance and a triaxial automotive-proven 16-bit gyroscope. Drones can take full advantage of the IMU’s superior vibration suppression and robustness and unmatched stability in dynamic conditions such as sudden temperature fluctuations. The BMM150 is a low power and low noise triaxial digital geomagnetic sensor designed for compass applications. Due to its stable performance over a wide temperature range, this geomagnetic sensor is especially suited for determining accurate heading for drones.

In addition to drones, the BMP388 provides a very flexible, one-size-fits-all solution for increasing the accuracy of navigation and fitness applications in wearables and smart homes, for example by utilizing altitude data to improve GPS precision or to determine floor levels inside buildings. It can also improve the precision of calorie counting in wearables and mobile devices, for example by identifying if a person is walking uphill or downhill when using a step counter.

With an excellent temperature coefficient offset (TCO) of 0.75 Pa/K between -20°C to 65°C, the BMP388 further improves the accuracy of altitude measurement over a wide temperature range. The new sensor provides an attractive price-performance ratio coupled with low power consumption and a high level of design flexibility – combined in a compact LGA package measuring only 2.0 x 2.0 x 0.75 mm³.

FIFO and interrupt functionality provide simple access to data and storage. This enables power consumption to be reduced to only 2.7 µA at 1 Hz during full operation, while simultaneously making the sensor easier to use. Tests in real-life environments have proven a relative accuracy of +/-0.08 hPa (+/-0.66 m) over a temperature range from 25°C to 40°C. The absolute accuracy between 900 and 1100 hPa is +/- 0.40 hPa over a temperature range from 25°C to 40°C.

Bosch Sensortec | www.bosch-sensortec.com

Low Cost 1 W DC-DC Converters Sport Dual Outputs

As a follow on to its R1SX 1W DC/DC converters, RECOM has extended its portfolio with the R1DX series to cover dual output voltage applications. The R1DX series is ideal for EIA/TIA-232 bus isolation and a wide range of industrial automation control equipment, sensors, isolated operational amplifiers and test and measurement equipment that require bipolar supply voltages.

The R1DX series are high-quality open-frame SMD converters, which deliver stable performance on symmetric dual outputs at a very competitive price. They operate from 5V and offer ±5, ±9, ±12 or ±15 dual outputs. There is no minimum load required, and the quiescent consumption is less than 150 mW. The pin-out is industry standard and compatible with the R1S/R1D series. High isolation of up to 3 kV DC (/H option) make them an ideal solution for isolating data transfer lines in legacy communication protocols (such as RS-232) and for isolated DAC and sensor applications.

The modules operate at a wide temperature range from -40°C to +95°C without derating and can drive up to ±1000 µF capacitive loads, which is multiple times higher than the competition. The series is fully certified to IEC/UL/EN62368-1 and UL60950-1 and is 10/10 RoHS-conform. Class A EMC conformity requires only an input capacitor and a simple low cost LC filter is all that is needed for Class B EMC. Samples and OEM pricing are available from all authorized distributors or directly from RECOM.

RECOM | www.recom-power.com

Next Newsletter: Sensors and Measurement

Coming to your inbox tomorrow: Circuit Cellar’s Sensors and Measurement newsletter.
May has a 5th Tuesday, so we’re bringing you this bonus newsletter beyond our normal four rotating weekly subject areas. While sensors have always played a key role in embedded systems, the exploding IoT phenomenon has pushed sensor technology to the forefront. This newsletter looks at the latest technology trends and product developments in sensors and measurement.

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
Sensors & Measurement newsletter issue tomorrow.

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

Embedded Boards.(5/22) 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. (6/5) 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 (6/12) 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.

Gesture Recognition in a Boxing Glove

Sensors Packed in the Punch

Learn how these two Boston University graduate students built a gesture-detection wearable that acts as a building block for a larger fitness telemetry system. Using a Linux-based Gumstix Verdex, the wearable couples an inertial measurement unit with a pressure sensor embedded in a boxing glove.

By Blade Olson and Patrick Dillon

Diagnostic monitoring of physical activity is growing in demand for physical therapists, entertainment technologists, sports trainers and for postoperative monitoring with surgeons [1][2]. In response to the need for a low-cost, low-profile, versatile, extensible, wearable activity sensor, the Hit-Rec boxing sensor is a proof-of-concept device that demonstrates on-board gesture recognition and high-throughput data monitoring are possible on a wearable sensor that can withstand violent impacts. The Hit-Rec’s ability to gather raw sensor values and run calculations at a high frame rate make the Hit-Rec an ideal diagnostic device for physical therapists searching for slight perturbations across a user’s gestures in a single recording session or for looking at discrepancies between the ideal motions of a healthy individual and the user’s current motions. The following sections will describe the implementation of a prototype for the Hit-Rec using a boxing glove (See Lead Photo Above).

SYSTEM OVERVIEW

The Hit-Rec sensor incorporates a Gumstix Verdex Pro running Linux, a 9-DoF (degree of freedom) inertial measurement unit (IMU), a pressure sensor that is connected to the Gumstix via a 12-bit analog-to-digital converter (ADC) and LEDs for user feedback. The ADC and IMU both communicate over I2C. The LEDs communicate to the Gumstix through general purpose input/output (GPIO). Figure 1 shows a high-level explanation of hardware interfaces and Figure 2 provides an illustration of the system overview. All software was written in C and runs exclusively on the Gumstix Verdex Pro. A Linux kernel module was written to interact with the LEDs from the user-space program that performs data capture and analysis. IMU data was smoothed and corrected in real-time with an open-source attitude and heading reference system (AHRS) provided by Mahony [3][4]. A circular buffer queue was used to store and retrieve sensor data for recording and analysis. Punch classification compares accelerometer values at each data point and chooses the gesture with smallest discrepancy.

Figure 1
This high-level diagram details the data transfer connections made between the main hardware and software components of the Hit-Rec.

Figure 2
Overview of the software architecture for translating IMU and Pressure data to user feedback

Each of three LEDs on the Hit-Rec glove represents a different gesture type. After the “punchomatic” program is started, the user is prompted to record three gestures by way of three flashing LEDs. In the background, IMU data is continuously being recorded. The first, yellow LED flashes until an impact is registered, at which point the last 50 frames of IMU data are used as the “fingerprint“ for the gesture. This gesture fingerprint is stored for the rest of the session. Two additional gestures are recorded in an identical manner using the red and blue LEDs for the subsequent punches. After three gestures have been recorded, the user can punch in any form and the Hit-Rec will classify the new punch according to the three recently recorded punch gestures. Feedback on the most closely related punch is presented by lighting up the corresponding LED of the originally recorded gesture when a new punch occurs.

SENSORS

We used the Adafruit LSM9DS0 with breakout board as an IMU sensor and a force-sensitive resistor (FSR) from Adafruit as a pressure sensor. Both sensors communicate over I2C, which the pressure sensor achieves through an ADC. …

Read the full article in the June 335 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.

IoT Edge Server Manages Distributed Devices

Advantech has announced its new generation of wireless connectivity: the Edge Intelligence Server EIS-D210 series. As smart cities and industry 4.0 deployment installs millions of IoT sensors and devices, wireless communications has become the fastest growing sector and wireless networks have been part of every application. As a result, the task of remotely managing distributed devices becomes more complex.

To echo market requirements, Advantech EIS-D210 series is powered by an Intel Celeron processor N3350 and has LoRa/Wi-Fi/Bluetooth and WISE-PaaS/EdgeSense edge intelligence and sensing software built-in. It is also pre-integrated with Microsoft Azure IoT Edge and AWS Greengrass to extend cloud intelligence to edge devices and enable real-time decisions at the edge. Advantech EIS-D210 is an integrated solution from the edge to the cloud and simplifies IoT application deployment. It’s well suited for applications in smart factory, smart energy and intelligent agriculture applications that need wireless sensor network management.

EIS-D210W has a built-in certificated Wi-Fi (IEEE802.11a/b/g/n/ac 2.4GHz/5GHz standard) and Bluetooth 4.1 module, and EIS-D210L incorporates a built-in private LoRa long-range modem. All EIS-D210 series have built-in dual GbE, COM (RS-232/422/485), VGA/HDMI, four USB 3.0 and mPCIe ports. The mPCIe ports can be extended to support 3G/4G LTE. EIS-D210 series provide several connection capabilities and peripheral support for multiple wireless/wired communications.

EIS-D210 series comes with Advantech’s WISE-PaaS/EdgeSense edge intelligence and sensing integration software, which provides an IoT SDK and documents for wireless sensor (LoRa, Wi-Fi, Bluetooth) data integration and supporting field protocols (MQTT/OPC/Modbus) for sensor/device data acquisition. With these, customers can quickly incorporate data integration, data pre-processing, and edge analytics to their applications.

EIS-D210 series is also pre-integrated with Azure IoT Edge and AWS Greengrass, ensuring that IoT devices can respond quickly to local events, interact with local resources, operate with intermittent connections, and minimize the cost of transmitting IoT data to the cloud. Furthermore, after data modeling and machine learning with data, results can be pushed back to edge (IoT Edge/ Greengrass) to provide data prediction for IoT applications.

EIS-D210W (Wi-Fi/Bluetooth) became available at end of April and EIS-D210L (LoRa) will become available in June.

Advantech | www.advantech.com