The wireless connected home

Paul Boughton

Silicon Labs has launched a series of reference designs to simplify the development of wireless connectivity in the smart home via the Zigbee and Thread protocols, writes Nick Flaherty.

These are the first in a series of designs for the wireless Internet of Things (IoT) and include the hardware, firmware and software tools that developers need to create interoperable, scalable products for the connected home. They are based on Silicon Labs’ ZigBee "Golden Unit’” Home Automation (HA 1.2) software stack and ZigBee system-on-chip (SoC) mesh networking technology.

IHS Technology forecasts that connected home device shipments will grow from 59 million units in 2015 to 193 million units in 2018, a compounded annual growth rate of more than 48 percent. According to IHS, successful connected home products must be standards-based, easy to deploy by mainstream consumers, and designed to work in real-world environments and solve specific problems with minimal complexity.

The reference designs are intended to significantly reduce the complexity of connecting ZigBee devices, such as lights, dimmer switches and door/window contact sensors, in a wireless connected home network. This design simplicity translates into ease of use for consumers who are increasingly purchasing ‘do-it-yourself’ connected home products at home improvement retailers.

The ZigBee connected lighting reference designs feature wireless lighting boards as well as a plug-in demo board suitable for quick demonstrations and testing. The Golden-unit ZigBee stack allows LED lights to reliably join, interoperate and leave a mesh network, as well as scale from a few to hundreds of light nodes on the same network. The connected lights can support white, colour temperature tuning and RGB colour settings as well as dimming.

The home automation reference designs include a capacitive-sense dimmable light switch and a small-form-factor door/window contact sensor. The light switch provides colour, colour tuning and dimming control capabilities that traditional switches cannot achieve.

Unlike conventional switches, these wireless, battery-powered switches have no moving parts and are easy to place anywhere in a home. The switch design features Silicon Labs’ EFM8 capacitive sensing microcontroller to detect different user gestures (touch, hold and swipe).

The contact sensor reference design provides all the tools needed to create wireless, battery-powered sensors used to monitor door and window positions (open or closed) – a useful feature for automatically triggering room lighting.

Silicon Labs offers two ZigBee gateway options to complement the reference designs. This provides a plug-and-play USB virtual gateway that works with any PC development platform and supports the Windows, OS X and Linux environments as a virtual machine. There is also a Wi-Fi/Ethernet gateway reference design based on an embedded Linux computer system.

Both gateway options allow developers to control and monitor ZigBee HA 1.2 compliant end nodes through Wi-Fi with any device with a web browser, such as a smartphone or tablet. Using an intuitive, web-based user interface, developers can easily create rules between ZigBee end devices including lights, dimmable light switches and contact sensors.

The connected lighting and home automation reference designs both use the EM358x mesh networking SoCs, combining an ARM Cortex-M3 processor core with a low-power 2.4GHz 802.15.4 transceiver. The low power designs enable very long battery life of up to three years for dimmable light switches and up to five years for contact sensors on a CR2032 coin-cell battery.

The mesh networking capability of the stack scales from tens to hundreds of nodes with individual selectivity, without costly rewiring of existing systems, and updates over-the-air will allow upgrades to Silicon Labs’ Thread software. The hardware is FCC/CE pre-certified for easy system configuration and fast time to market and the complete schematics, layout and bill of materials (BOM) are supplied.

“Developers creating connected home products want simple, high-performance, battery-friendly solutions that make wireless design fast, easy and straightforward,” said Greg Hodgson, senior director of IoT Solutions at Silicon Labs. “Our new connected lighting, home automation and ZigBee gateway reference designs meet these developer priorities, providing the most robust, easiest to use hardware/software solutions available.”

The connected lighting, home automation and smart gateway reference designs are available today. The RD-0020-0601 and RD-0035-0601 connected lighting reference designs are priced at $49. The RD-0030-0201 contact sensor reference design is priced at $39. The RD-0039-0201 capacitive-sense dimmable light switch reference design is priced at $29. The USB virtual gateway is priced at $49, and the out-of-the-box Wi-Fi/Ethernet gateway reference design is priced at $149.