IC design trends for sensors and nodes

IC design trends for sensors and nodes
Level of integration, energy efficiency, intuitive technology, IP-Based and mesh networks are the main design trends of key components applied for smart home sensors and nodes. These makers aim to provide smart home suppliers with maximized benefits such as low BOM cost, shortened time to market and steady device performance.
 
Smart home products are composed of home hubs and sensors. These sensors are also called nodes or edge devices, and their hardware performance is heavily relied on the microcontrollers (MCUs) and connectivity ICs. MCUs can perform real-time processing, gather sensory information and communicate with other connected devices.
 
MCUs have been gaining traction with an increasing demand from Internet of Things (IoT) and smart home. The research firm Information Network’s research shows that smart home MCU consumption will increase the greatest at a compounded annual growth rate of 35 percent in 2020, while smart cities' application share will drop to 48 percent of MCU consumption from 54 percent in 2014.
 
Seamless connectivity among nodes is crucial for high performance of the devices and good user experiences at smart home.
 
Wei-Ning Gan, Head of SEEDS Business Unit at Marvell Semiconductor said, “The IoT design should emphasize on high connectivity rather than high bandwidth. We believe there are a considerable number of sensors that require low data rate. The reliable connectivity is essential. How to extend battery life of wireless connected devices is also critical.”
 
After speaking with IC companies, SMAhome sees the technological trends of ICs design for smart home sensors and node devices moving toward low cost, high energy efficiency, IP-based communication and mesh networking, high level of integration, and voice control. The ARM architecture dominates the embedded systems. The majority of embedded design in the smart home sensors and nodes are based on ARM Cortex-M and Cortex-R architectures.
 

Low cost and high integration

To lower cost and size, chip companies have released integrated SoCs that bring together the microcontroller function and connectivity. The beauty of the highly integrated solutions is that they can lower bill of materials (BOM) remarkably.
 
For example, CSR BlueCore CSRB5348 dual-mode system on chip (SoC) provides module manufacturers with significant BOM savings while speeding time to market for multiple IoT applications. It integrates microcontroller, battery charger, and analog and power management into a single platform. As wireless MCUs are popular offerings in the market, TI’s SimpleLink CC2630 wireless MCU supports IEEE 802.15.4-based networking solutions and easy IP and cloud connectivity through 6LoWPAN operation where each device includes an IPv6 address. Broadcom’s BCM20706 integrates Bluetooth Smart onto a single chip with a built-in ARM Cortex-M3 MCU, enabling twice the data rate over a Bluetooth Smart link, and power-efficient 2 Mbps mode, anticipated to be standardized in Bluetooth 5.0.

It’s a trend to drive the IC’s cost down to $1 or lower for putting it into the mainstream market. For example, the price of ARM Cortex-M0 microcontroller is available at less than $0.5. Cees Links, CEO of GreenPeak Technologies said, “At present, a ZigBee chip costs around $1 or lower. Low cost is very critical for mass adoption. We are working very hard to drive the cost down.”
 
Some solutions further incorporate more than one communication protocol for future-proof performance. Matt Saunders, Director, Field Marketing of MCU and Wireless Products at Silicon Labs thinks that a successful IoT end node needs to integrate more functions and reduce components. Saunders of Silicon Labs said, “Cost and the size have to decrease, and the level of integration has to increase. Users may need to deal with two or three different protocols at the same time. It’s essential to find the right level of integration to develop cost-effective and simple-to-use systems.”
 
We see combo or hybrid SoCs supporting dual protocols like the combination of ZigBee and Thread, and Wi-Fi plus Bluetooth. GP691 ZigBee communications controller provides IEEE Standard 802.15.4-compliant spectrum in the worldwide 2.4 GHz band, supporting ZigBee 3.0 and Thread. Marvell’s 88MZ300 802.15.4/ZigBee wireless microcontroller system on a chip (SoC) also supports ZigBee 3.0 and Thread. Thread integrates multi-protocol radio that makes it easy for connected devices to talk to more than one of those protocols simultaneously.

Links of GreenPeak indicated that it’s an important trend to integrate different protocols into one chip like the integration of Bluetooth and ZigBee. Hence, users can use their smartphones to connect smart home devices to the cloud. Links said, “We can expect to see combo ZigBee-BLE chips in the near future. Besides, it’s an important trend to integrate different protocols into one chip like the integration of Bluetooth and ZigBee. Hence, users can use their smartphones to connect smart home devices to the cloud.”
 

Accelerating time to market

Time-to-market is the key to success in smart home. The IC suppliers provide production-ready modules, peripheral-rich solutions, and platforms that comprise multiple chips and SDK to address clients’ needs. Gan of Marvell said, ”We offer IoT modules, or so-called smart modules, which comprises microcontroller and wireless connectivity solutions based on Wi-Fi, BLE and ZigBee standards. For example, we offer IoT modules for Xiaomi’s smart plugs and air purifiers, and for home appliance makers like Whirlpool, and Midea.”
 
MediaTek’s approach is to offer tailor-made solutions to address different market needs shortly. SR Tsai, General Manager of Wireless Connectivity and Networking Business Unit at MediaTek said, “We offer many SoCs with integrated processor, connectivity and power management functions.” Its Linux-based MT7688 SoC is designed for the smart appliances with complex features, such as IP camera and home surveillance that require high data transmission rate; while on the other hand MT7681 is based on MediaTek’s RTOS and is suitable for simple applications due to its compact size, including smart plug, lighting fixtures and sensors. MT7687 is MediaTek's first ARM Cortex-M4 IoT Wi-Fi SoC with an enhanced security engine, designed for IoT end devices.
 
For fast deployment, Sigma Designs launched the Embedded Development Kit for end-devices, such as remotes, sensors, switches, door locks, lights, sensors and thermostats, running on RF868, 908 and 920 MHz. The solution provides quick prototyping with embedded sample applications and Z-Wave RF modules. It also provides application framework, for building new software applications, to modularize the codes with predefined applications for easy task deployment. The versatile development modules enable easy hardware prototyping.
 
Jeff Baer, Product Marketing Director of Broadband & Connectivity Group at Broadcom Corporation indicated the real differentiator from the competitor is not just providing a chip. “Even if you give IoT customers great chips at a compelling price, they don’t exactly know what to do with that–it’s too complex to integrate.
 
Our WICED architecture offers the complete environment to pull the software, API, and hardware together, creating a complete and easy-to-implement hardware and software solution for time-to-market deployment. That’s what the companies in the United States and elsewhere are looking for. They don’t just look for the super chips or cost-effective solutions, but a complete solution can be easily integrated into existing products. This is one of the challenges when working with original equipment manufacturers who do not have extensive background in radio frequency, which is a core strength of ours.”  
 

Energy efficiency

Saunders of Silicon Labs said, “A successful connectivity technology for IoT must be energy efficient. There’s an effort to bring low-power Wi-Fi, but it’s still not really coin-cell friendly with transmission requirements being up in the hundreds of mA current range to deliver messages.
 
When we’re talking about energy efficiency here, we’re referring to very low active current consumption for microcontroller, exceptionally low standby currents. ”The company offers low-power solutions featuring low active and standby power consumption like EFM32 and Blue Gecko based on Sub-GHz and BLE technology.
 
ZigBee is another power-saving technology. For instance, GreenPeak claims its GP490 is cable to operate on a coin-cell battery for over 10 years, eliminating the maintenance problem of frequent battery replacement.
 
At present, short battery life is a key challenge for wide adoption of wireless connected devices. To solve the problem, Marvell has developed FLC (Final-Level Cache) technology to extend battery life by redefining main memory hierarchy. With FLC, there will be an increase in standby time by 10 times, and 100 times increase with MRAM FLC in the future. The design enables solutions with a smaller form factor and less power consumption.
 
DSP Group's DHAN module offers application developers a turnkey platform for Ultra Low Energy (ULE) nodes, both battery and AC-powered. Built around the company's DHX91 SoC, the module can easily integrate into the smallest Smart Home nodes and can serve as a wireless connectivity channel for applications running on external MCUs, or act as a standalone solution using DHX91's internal processor.
 
“Consumers want a simple, secure smart-home experience that works with a wide range of devices and smartphones. The set-up process has to be simple and low maintenance with minimal need to change batteries,” says Anthony Murray, Senior Vice President, Business Group at CSR. “This latest version of CSRmesh meets increasing consumer demand for a much wider range of home automation applications that are seamless and secure.”
 

Intuitive technology

It’s a trend to add voice control to make the nodes smarter and easy-to-use. Voice control is regarded as a promising intuitive technology. NXP’s LPC5410x is a dual-core ARM Cortex-M4F and -M0 based microcontroller, applied for voice-triggered IoT nodes. STM also offers a voice-control module that incorporates MEMS microphones and Cortex-M4 microcontroller. The device supports BLE technology and turns on the light via voice commands.
 
Raz Kivelevich-Carmi, VP Marketing & Business Development, DSP Group indicated that what makes ULE special and competitive is its voice control technology that makes the interaction with other devices more intuitive because it’s originated from DECT technology. Kivelevich-Carmi said, “ZigBee and Z-Wave can’t play the video because they don’t have the bandwidth, and are not built around the voice technology. Wi-Fi technology has the bandwidth, but it isn’t low-power.” He believes interactions in the future smart home will be through voice technology, not touch technology.
 
Besides voice control, NXP’s JN5169 wireless microcontroller and accompanying smart home and smart lighting solutions, features a NFC-commissioning option that allows users to connect systems intuitively with just one tap. The solution supports ZigBee Light Link (ZLL), Home Automation and GreenPower software stacks.
 

IP-Based and Mesh Networks

There is an increasing demand for connecting the nodes to cloud servers and platforms via IP-based communication. With more and more connected devices at home, it is necessary to integrate mesh network technology and different levels of integration to enable seamless connectivity for a large number of devices working together within a long range. Thread, BLE 4.1, ZigBee 3.0 and Z-Wave protocols support IP connectivity.
 
Saunders of Silicon Labs said, “The expected growth for IoT is coming because this is a technology that’s going to be applied to every aspect of our lives. In the mobile handset space, it’s an average number between 1.5 and 2 units per person in any developed country. If we push that forward to where we’re projecting the Internet of Things, there will be 45, 50 or even more nodes that a person have in a house.”
 
It’s fancy to offer hub-less design when every node has its own IP address to link to the IP layer and cloud directly without buying a discrete hub. The sensors and nodes don’t require a hub or router to function locally. Nordic Semiconductor promotes IPv6-based communication technology to enable the nodes to be connected to the cloud without a smart home gateway or hub. Richard Chen, Regional Sales Manager of Nordic Semiconductor explained, “Our IPv6 over BLE technology, compatible with current networking equipment, helps accelerate the mass adoption. There is no need to create a new way for connected home.
 
In August 2015, CSR announced CSRmesh Home Automation based on BLE technology for the smart home regarding control of heating, ventilation, air conditioning, door locks and window sensors. The sensors and nodes does not require a hub or router to function locally, or an end-to-end IP connection, providing simple and seamless user experiences. CSRmesh for Home Automation claims to significantly extend battery life for sensors and actuators such as door locks. Manufacturers can reduce the duty cycle of each mesh device to as little as two percent by grouping sensor devices with a mains powered proxy device, and holding data from a battery powered sensor device. This proxy device can then relay that information without ‘waking’ the battery powered sensor. The sensors and nodes would be in sleep mode at all other times, and only wake up when they are triggered by user activation such as a window being opened.
 
Thread technology is a new and IP-based wireless networking protocol designed for low-power connected products in the home, using proven standards like IPv6 and 6LoWPAN. Millions of existing 802.15.4 wireless devices like ZigBee-compliant devices already on the market can run Thread with just a software enhancement without new hardware required. The sensors will have their own IP addresses for more smooth and secure communications based on IPv6 and 6LoWPAN technologies.
 
Bluetooth also supports IP connectivity since its 4.1 version, allowing Bluetooth Smart sensors to access the Internet directly via IPv6 and 6LoWPAN. It is ideal for connected home scenarios that need both personal and wide area control.
 
Seamless connectivity among nodes is crucial for performance of smart home devices. Eliminating battery changes increase operating convenience. While there are still arrays of technological plights to be diminished, IC makers and smart home suppliers are working together to improve user experience.
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