Wireless Sensors Work Harder than Ever



Industrial wireless sensor networks are increasingly used to track and monitor, but integration and intelligence mean they also protect and add security.

The use of sensors in industrial applications is increasing, as industries and processes require increased levels of monitoring, tracking, and data collection. Industrial Wireless Sensor Networks (IWSNs) are being deployed faster as they are low-cost, not only where cabling and wiring expense is concerned, but for installation as well. IWSNs can be integrated into smartphones and other connected devices for wider coverage and to improve productivity and maintenance. And wireless networks suit hazardous or hard-to-reach areas in industries such as mining or chemicals.

“The mmWave sensors can sense accurately through plastic, dry wall, clothing, glass and many other materials, and through environmental conditions such as lighting, rain, dust, fog, or frost.”

In 2016, the IWSN market was estimated to be worth $588.91 million (Zion Market Research market report) and is expected to achieve a compound annual growth rate (CAGR) of 12.7 percent in the five years from 2017, to be worth $1,204.54 million in 2022.

Figure 1: Wireless sensor networks are used to track and monitor, but Texas Instruments says its IWR and AWR radar sensor families will disrupt the market. (Picture credit: Texas Instruments)

Figure 1: Wireless sensor networks are used to track and monitor, but Texas Instruments says its IWR and AWR radar sensor families will disrupt the market. (Picture credit: Texas Instruments)

The enormity of the IWSN means that it encompasses chemical and gas, humidity, motion and position, temperature, pressure, level, flow, and image and surveillance sensors. The growth in so-called smart factories brings challenges such as employing multiple wireless technologies, such as Wi-Fi, Bluetooth, ZigBee or Wireless HART, based on the Highway Addressable Remote Transducer (HART).

Security concerns to protect access to both data and the network infrastructure are coupled with energy consumption to ensure an accurate network, operating with longevity in harsh environments.

Texas Instruments has introduced a family of single chip, millimeter wave (mmWave) sensors that addresses some of the challenges currently faced by mmWave technology, namely accuracy and size. At the launch of the AWR and IWR sensor families, for automotive and industrial use respectively, Greg Delagi, Senior Vice President, Embedded Processing, at Texas Instruments, said the single chip mmWave sensors render “what ultrasonic sensors are doing today as redundant.”

Figure 2: Greg Delagi, Texas Instruments. Single-chip mmWave sensors render “what ultrasonic sensors are doing today as redundant.”

Figure 2: Greg Delagi, Texas Instruments. Single-chip mmWave sensors render “what ultrasonic sensors are doing today as redundant.”

He believes that the Complementary Metal Oxide Semiconductor (CMOS) chips are overcoming the limitations of CMOS. The project was nurtured in research and with engagement from Original Equipment Manufacturers (OEMs), he says and will “disrupt the [Silicon Germanium] SiGe world and [that] CMOS will replace SiGe technology.” In terms of range, they are superior to SiGe sensors, confirms Delagi.

mmWave Sensor Technology
There are two families, with five options of integrated sensors, combining Digital Signal Processing (DSP) and/or a microcontroller in a single, compact package. The AWR mmWave sensors are for automotive applications. They can be used in front, long range radar to detect moving objects as well as in multi-mode radar and short range radar.

For industrial applications, the second family is the IWR mmWave sensors. They can be used for level sensing, traffic monitoring, detecting vehicle movement and velocity, and for drones.

Texas Instruments believes it is the smallest footprint CMOS sensor portfolio available today at just 108-mm².

Delagi explains that the CMOS chips, with integrated mixed-signal design and real time signal processing, contribute to accuracy levels. Each chip delivers smart, accurate stand-alone sensing with less than a 40mm range resolution, with range accuracy down to less than 50µm, and range up to 300m. They are 10x more accurate in detection than ultrasonic sensors, said Delagi—able to detect detail down to the width of a human hair. They are also low power and scalable, he adds.

The IWR mmWave sensors can be used in medical equipment, tank-level sensing, robotic vision and drones. They sense materials and environmental conditions like rain, smoke or dust—all sensing challenges, says Delagi. “Microwave technology is the only sensing technology robust enough to meet these kinds of challenges,” he says. The IWR1x mmWave contactless sensors can be used indoors and outdoors, without interference from lighting, rain, dust, fog or frost. Their small size means they can be used in weight- and space-constrained applications. In drones, for example, they can be used to navigate, detecting power lines. The sensors will also enable the drone to navigate and determine the range, velocity, and angle of objects around it and adapt dynamically.

Figure 3: Sameer Wasson, Texas Instruments, “mmWave sensors are more robust.”

Figure 3: Sameer Wasson, Texas Instruments, “mmWave sensors are more robust.”

Sameer Wasson, General Manager, Radar and Analytics Processors, at Texas Instruments, adds “The mmWave sensors can sense accurately through plastic, dry wall, clothing, glass and many other materials, and through environmental conditions such as lighting, rain, dust, fog, or frost. The limitation is that that they can’t penetrate metal or travel through water, but they can be used to measure water levels. In many places, they make sensing more robust, using one sensing topology—it’s always about the technology,” he says.

In the IWR sensor family, there are two devices, the IWR1443, based on an ARM Cortex-R4F Central Processing Unit (CPU) with a radar hardware accelerator. The IWR1642 has the same CPU core and a TI C67x DSP. Monitoring traffic and perimeter security are commonplace today, but these RF sensors use radar to detect movement and guide the surveillance device to the specific area where movement is detected. In dark environments, this is particularly useful for security and safety as well as reliability.

Figure 4: The IWR1642 RF sensor from Texas Instruments integrates a CPU with DSP.

Figure 4: The IWR1642 RF sensor from Texas Instruments integrates a CPU with DSP.

Automotive Sensing
The automotive family consists of the AWR1243, a standalone radar sensor, used for occupancy and high-end applications, the AWR1443 high-resolution sensor with the same ARM Cortex-R4F CPU and radar hardware accelerator, and the low-power AWR1642, which integrates both DSP and MCU, using the ARM Cortex-R4F and TI’s C674x DSP. Combining an RF front end, MCU, and DSP means it can be used to detect pedestrians or cyclists, using a 360-degree view, as well as detecting objects in what are called blind spots and objects to avoid while reversing the vehicle. The dynamic multi-modal operation allows the sensors to switch from high-speed to parking manoeuvers. Delagi expects the sensors will be in vehicles and on the roads by early 2018.

All five sensors operate in the 76- to 81-GHz frequency range and are available for sampling now, together with evaluation boards. A software development kit is also available. It has sample algorithms and software libraries.

Network Control
Controlling wireless sensor networks is conventionally done in a control room, but as connectivity increases, control can be performed using wireless, connected devices, such as smartphones and tablets to extend the range and reach.

To integrate local sensor networks into the Cloud, congatec has developed the Cloud Application Programming Interface (API), the Cloud API for Internet of Things (IoT) gateways, and IoT edge servers (Figure 5).

Figure 5: The congatec Cloud API for IoT Gateway manages data from machinery and other IoT applications.

Figure 5: The congatec Cloud API for IoT Gateway manages data from machinery and other IoT applications.

It communicates with local smart sensors to acquire data, which it processes and converts to execute automated actions based on a local rule engine. This reduces traffic to the IoT cloud, while the Transport Layer Security (TLS) -secured Message Queuing Telemetry Transport (MQTT) protocol ensures secure bi-directional data exchange with any Cloud. At Embedded World 2017, congatec introduced a best practice design using the Microsoft Azure cloud, which can be accessed via https in client or administrator mode.

The API can integrate Bluetooth Low Energy, ZigBee, LoRa, and other Low Power Wide Area Network (LPWAN) wireless sensor interconnects, as well as wired protocols. Even heterogeneous protocol configurations and communication with other gateways are possible, says the company, which are typically required for Industry 4.0-connected machines and intra-logistic systems. The sensor engine makes communication with the local sensor and actuators independent from any protocol.

congatec defined a best practice with Cloud API function modules (software modules) with demo and test modules for provider-independent IoT clouds. Among the library’s gateway system parameters are system temperatures, CPU workload, and intrusion detection to manage the workload. The rule engine enables the gateway to locally initiate warnings and automated actions if values exceed or threaten to exceed specified thresholds.

The communication engine manages encrypted and provider independent data cloud communication via wired or wireless Internet connections. IoT cloud evaluation software consolidates the sensor data in the Cloud, sets central messaging and control rules for the applications, and provides the dashboards for remote clients.

The Zion Market Research report notes that the adoption of smart factories and intelligent manufacturing will fuel the growth of IWSNs in North America, the largest market, and in Asia-Pacific, the fastest emerging market, as low-cost networks are eagerly consumed by the growing industrialization in India, Taiwan, and South Korea.


hayes_caroline_115Caroline Hayes has been a journalist covering the electronics sector for more than 20 years. She has worked on several European titles, reporting on a variety of industries, including communications, broadcast and automotive.

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