Sensors Mag

The Rise of Sentrollers

November 15, 2013

Sensors Insights by Cees Links

The lines between everyday devices like televisions, computers, and phones are blurring. All of these devices consume or provide content (e.g., text, mail, audio, and video) and rely on Wi-Fi connectivity to access the Internet via a home router or gateway. There is, however, another class of devices in the home that consumers increasingly would like to see connected to the Internet—devices they would like to be able to monitor and manage from anywhere. These include thermostats, lights, door and window locks, heaters, air conditioners, and monitoring/security systems. All of these fall into one of three categories: sensors, actuators, or controllers, and they are usually small, infrequently activated, and without Internet connectivity. This is the family of "sentrollers," and the next generation of technology will see these devices connected to the Internet, driving the emergence of truly smart homes.

Bringing Smart Technology Home
To get a better idea of what these smart homes will be like, consider today's automobiles. Virtually everything measurable in cars today (e.g., speed, engine temperature, and tire pressure) and to a certain extent controllable (e.g., windows and door locks) can be accessed from behind the steering wheel.

Until recently, this smart technology was expensive to deploy in the home, but that's changing, as the ZigBee wireless standard is used to connect sentrollers to home gateways and set-top boxes. Many modern set-top boxes and satellite transceivers already contain ZigBee radio chips to communicate with remote controls (replacing infrared). Because these boxes are ZigBee-enabled, it is a small step to connect devices like security sensors, lights, and thermostats to the boxes and have set-tops or gateways function as the home control box for sentrollers. Once connected to the box, a network of sentrollers can easily be managed and monitored—not only from a remote control in the home but also from a smart phone anywhere in the world.

Why ZigBee?
With all of the flavors of wireless available for home automation, why should ZigBee play such a key role? The answer lies in the fact that Wi-Fi is about content sharing and distribution, placing a premium on high data rates. Unfortunately, these types of applications are hard on battery life. In contrast, ZigBee is not suitable for content sharing. Its speed is anywhere from 100 to 1,000 times slower than Wi-Fi. On the other hand, ZigBee is all about low power. Sentrollers equipped with ZigBee communications usually have a battery life that exceeds the life of the product, or—as is the case with GreenPeak's ZigBee implementation—they do not need a battery at all. A ZigBee-enabled light switch can operate on the energy harvested from the flip of the switch. ZigBee uses less than 1/100th the power of low-power Wi-Fi implementations.

The availability of a low-power, global standard will help to drive down the cost of sentrollers, from $100 or more per device today to between $5 and $10 in the near future. This is helping the market to rapidly develop and makes it interesting for product builders to think about larger volumes of sentrollers that can work together to provide combined applications using technologies like cloud services.

An example of these combined applications would be a motion sensor that is part of both a home security system and an energy management system. When the security system is deactivated and the sensor detects motion, the sensor turns on the light in the room and the heating or air conditioning system. However, if the security system is active and the sensor detects motion, it will trigger the security alarm, indicating that an intruder is in the home.

Expanding Smart Services
The "smart home" concept can easily be extended to a broader variety of sentroller systems. For instance, when the system "understands" that a window in a room is open, it automatically turns off the air conditioner. So the window sensor should also be integrated with the energy management system, connected via the home control box to the cloud to monitor the overall consistency of the usage of all the equipment in the home.

The word "sentrollers," therefore, not only describes a world composed of sensors and controllers but also of intelligence. All the sentrollers are connected via a home control box to a smart cloud application that carefully manages the interactions of all the devices, comparing their status with what is desired and taking action without human intervention. In this way, the rise of sentrollers is all about making our lives more secure, managing energy consumption better, and increasing the comfort of our homes and our lives.

Cees Links is the founder and CEO of GreenPeak. He can be reached at or +31 30 262 1157.

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