by LELAND TESCHLER, Executive Editor
Market studies show consumers are less enthusiastic about connected products these days. But electronic suppliers are still designing components and software aimed at quickly implementing the Internet of Things.
Go to YouTube, type in Internet of things, and you’ll find enumerable videos and TEDx talks all foreseeing a future where each person will be surrounded by thousands of everyday “things” connected to the Internet. But the prognosticators making these claims apparently forgot to check with real consumers about preferences for connected homes and lives.
Or at least that might be one take-away from recent market studies by Argus Insights, a consumer and enterprise marketing analysis firm in Los Gatos, Calif. Argus says it has seen a significant slowing in consumer demand for staples of the IoT that include both wearables in general and fitness bands in particular. According to John Feland, Argus CEO and founder, “Consumers expect their wearables to do more than simply count steps, just as they expect to do more than just make phone calls with their handsets. … Fitbit and others in this category will need to add more to their offerings to keep consumers engaged and coming back for more.”
Similarly, Argus recently found that the home automation portion of the IoT market is quickly losing steam. Its data show that as of a few months ago, consumer demand for such connected home devices as thermostats, lightbulbs, locks, sensors and cameras experienced its first drop below the level of a year ago, a sign that consumer interest is stagnating.
Suppliers with their eyes on IoT business admit there are difficulties slowing the predictions of an interconnected world. One big obstacle is all the communication protocols now associated with wireless technology and the Internet. Bluetooth, ZigBee, IEEE 802.11p, LTE and several others are all considered mainstream standards. The plurality of standards is a problem, say suppliers. “There are no global industry standards for IoT or connected devices,” said Andrew Caples, Mentor Graphics’ product manger for the Nucleus real-time operating system. “Fragmentation makes IoT adoption more challenging. There is a need to establish IoT standards that are embraced by specific vertical markets as well as horizontally across many industries. With established standards, IoT adoption would accelerate to the benefit of the consumer.”
Power supply maker CUI says the smart home is a great example. There are a number of proposed protocols available, including Z-Wave and ZigBee. Consumers need to ensure their HVAC, lighting, audio/visual and security systems speak the same language. But this equipment typically comes from multiple manufacturers, so the task of getting them to talk is challenging.
But indications are these obstacles aren’t stopping electronics suppliers. Component makers say the quest for smaller and cheaper IoT technology is driving several developments in hardware and software. “As more things become part of the IoT, we’ll be dealing with smaller devices that deliver more intelligence. With that in mind, we strive to improve power efficiency and latency and design improvements for where the data needs to be processed,” said Intel Corp. General Manager Bridget Karlin. She also said that because of the IoT, “our components and solutions are more policy-driven, allowing for greater security and control over deployed devices.”
Other semiconductor makers echo these sentiments. “As the IoT continues to evolve, we expect engineers will continue to see innovations from semiconductor vendors geared toward low-power devices and integration, such as more advanced on-chip security capabilities for low-end devices,” said Gil Reiter, Texas Instruments, director, strategic marketing, IoT. “These trends will drive more battery-operated IoT designs. Better memory and processing capabilities on microcontrollers and processors will enable the design of smarter devices capable of making more local decisions.”
The same trend toward smaller packaging is evident in electronic passive components. “As more things become connected, more care must be given to certain types of isolation. Connected machines, motors and devices have created the need for common-mode chokes for EMI compatibility as well as miniature isolation transformers,” said Len Crane, director of technical marketing, Coilcraft. Coilcraft makes chip inductors, power magnetics, EMI filters, wideband transformers and similar magnetic components.
Much has been written about the continual shrinking size of semiconductors, but the IoT is forcing passive components to get smaller as well. “We’ve made huge advances in recent years, particularly with our XAL/XFL families of ultra-small, ultra efficient power inductors,” said Crane. “They are built using wirewound construction and housed in rugged, magnetic-shielding bodies.”
To get a sense of the demands IoT applications can put on passive components, Crane relays a situation that cropped up recently in an energy harvesting product. “We were asked to develop a miniature flyback transformer for low-voltage step-up. That is where our LPR6235 Series came from,” he said. “It measures just 6 mm square and 3.5 mm high with turns ratios from 1:10 to 1:100. This application wasn’t realistic 10 years ago, both from the energy supply and consumption sides of the equation. Compact energy harvesters have reached a price point that can make sense, and power consumption has now been reduced to the point where these applications can be supported by harvested energy.”
Similarly, the advent of smaller electronics has forced makers of power supplies to develop more power-dense modules able to work at low voltages. CUI says the trend has accelerated as processor and FPGA designs have pushed supply voltages down to 1 V or less. As a result, voltages in the 1.8 to 3 V range are only used for specialized I/O devices that interface to memory and peripherals. But CUI points out that the maximum power envelope of server processors and FPGAs is still on the order of tens of watts, and pushing more than 100 W for the highest-performance products. The result is a current demand that is beginning to exceed the 100-A level at the point of load (POL).
To handle such needs, CUI recently released a 3-kW hot-swap power supply with PMBus capabilities called the PSE-3000. It has a power density of 33.5 W/in.3. To address the high current/low voltage demands at the POL, the firm recently released a 90-A digital non-isolated module (NDM3Z-90) designed specifically to provide high current and precise voltages as low as 0.6 V.
Communicating across the IoT
Obviously, there will be a lot of traditionally “unconnected” objects that will start sporting communication features once the IoT gets rolling. Signs of the trend are already emerging. An example comes from the realm of position encoders used for gauging the position and speed of rotating shafts. Rotary encoders from CUI nowadays contain an ASIC and an MCU. The electronics imbue the encoders with control features including the ability to programmatically set resolution, zero point and commutation signals with GUI software. Additionally, the encoders sport onboard diagnostics to aid in field-failure analysis. The encoder can be queried to indicate if it is operating properly or if there’s been a failure from a mechanical misalignment on the shaft or from other issues.
The same type of features can implement preventative measures. In the case of CUI encoders, for example, a test sequence run before starting an application can verify the encoder is supplying valid data.
With all the digital entities that the IoT will network together, it might be easy to become bogged down with the sheer volume of connections. Real-time operating systems (RTOSs) will likely help head off such problems because they can do so without introducing delays.
RTOSs have been widely applied for decades in control systems handling applications such as car engines and industrial process control. An RTOS meets control deadlines deterministically, running and executing tasks within a guaranteed time frame.
A complicating factor, though, is that devices being connected to the IoT are quite diverse. There are a variety of processors and brands of processors handling control tasks and running connected devices such as cell phones. And IoT processors work with memory sizes that can sometimes be quite small. The result is that an RTOS destined for IoT use needs an ability to scale—supporting a broad range of devices packing a variety of memory and processing power combinations.
The diversity also increases the likelihood of security vulnerabilities. To stay ahead of hackers, devices forming the IoT must be remotely managed and updated. Consequently, more RTOSs are moving to a modular approach that facilitates rapid upgrades, based on a stable core and add-on components.
An example of an RTOS built with the IoT in mind is one called Nucleus from Mentor Graphics. Nucleus Product Manager Andrew Caples described it as featuring a small footprint with IoT and M2M connectivity protocols, networking middleware and security, all scalable to conform to resource-constrained devices. Nucleus also has a built-in power management framework designed to handle the low-power features in processors and SoCs so applications can be written to minimize power consumption to extend battery life.
Many IoT applications tend to sit in cramped quarters that limit the volume available for electronics. With this reality in mind, Nucleus supports memory space partitioning. This is an ability to allocate memory resources based on the use case, Caples explained. Memory partitions can be used to load application processes when required; they can be unloaded to free-up memory. This feature is particularly helpful, said Caples, for wearable products that tend to be based on multicore SoCs. “Although the systems are limited in resources, they still include complex user interfaces, middleware, and of course, connectivity. Not only is small footprint a requirement, but the ability to leverage the existing resources is an absolute must,” he said.
High priority for low energy
It has been an old truism that an army marches on its stomach. In the same regard, it might be said that IoT technologies often get implemented because of their batteries. Much of the IoT is battery powered, so there’s a need for designers of these IoT devices to thoroughly characterize and understand the dynamic energy use of their designs. The necessary measurements can be challenging because of the dynamic nature of the current; a lot of IoT devices transition between sleep current to a much more energy intense active state. The result is a low and pulsing current with fast rise and fall times over a wide dynamic range.
Instrument makers have developed equipment specifically designed for measuring these kinds of waveforms. Keysight Technologies, for example, now markets instruments with the ability to accurately measure 10 sec worth of sleep currents in the microamp range, while also recording currents of 2 amps or more, both in a single measurement pass.
Instrumentation able to handle this kind of range was unavailable 10 years ago; designers back then could only capture current spikes in the ampere range in one pass, microampere-level currents in another. Though this procedure might have given an idea of the steady state current situation, it would have introduced inaccuracies.
An insulin infusion pump illustrates how a wide dynamic range can be handy for gauging electrical current. In one case, engineers measured dynamic current drain (not just average current) while evaluating different battery types. They also had to analyze the current drain profile and document the test results for FDA audits. Use of a Keysight DC Power Analyzer (N6705B) helped characterize the drain profile by means of its data logging mode. Developers measured the initialization pulse, pump current pulse, keypad press current and sleep current.
Other kinds of equipment have also been developed for IoT applications, including the Keysight EXM wireless test set. It can test multiple, multi-format wireless transmitting devices simultaneously. Keysight continues to add applications to address the formats widely used in the IoT; including 802.11p, 802.11ah and 802.11af.
A typical application for these instruments is the testing of RF modules built into the gateways. A gateway is a network node equipped for interfacing with another network that uses different communication protocols. Gateways may contain both cellular and non-cellular transceivers. The RF modules that are built into these gateways must be tested for various cellular and non-cellular formats (Bluetooth, ZigBee, WLAN, LTE and others).
The Keysight one-box tester, the EXM (E6640A), or the Keysight X-Series signal generator and signal analyzer are frequently used to test RF modules for these various wireless formats. Typically, X-Series signal generators and analyzers serve in product development where there’s a need for high RF performance and flexibility to run a variety of tests as for multi-channel MIMO (multiple input, multiple output) testing. The EXM one-box tester often serves in design validation and also manufacturing. Both instruments use the same software tools.
In one case, engineers used the EXM one-box tester to test an IEEE 802.11p WLAN module targeted at vehicle-to-vehicle communications. Unlike IEEE 802.11a, which targets higher data rates, the goal of 802.11p is reliable communication. Testing requirements, consequently, are much more stringent than for other WLAN standards. For example, 802.11p has much stricter spectrum emission mask (SEM) requirements for class C and D devices.