Many industries — whether electronics, consumer, or semiconductor — have a clear vision of the future of the connected smart home. While there are many use cases and some elements such as smart speakers and smart lighting that are already starting to take off, the full significance of a “smart home” may not be clear to the average consumer. The key to acceptance and adoption will be enhancing total ease of ownership — IoT elements need to be easy to install, use, understand, and maintain, all in an environmentally-sound way. One critical element in making these devices easy for homeowners to use is advanced sensor technology that draws little power or even harvests its own energy to run.

Sensing — The Smart Home Needs to Be Aware

A critical enabler for the smart home to actually be smart will be real-time sensing that allows the Internet of Things (IoT) to decide exactly what the “things” need to do. Widely deployed sensing becomes the gateway to an internet of awareness that will feed the IoT, delivering the right services at the right time to usher in a new era of efficiency and convenience that consumers will be willing to pay for.

But what is a “smart” home? There is a tendency to define the smart home in terms of the more visibly interactive examples of the technology, such as the voice-activated devices from Amazon and Google that are becoming commonplace and smart lighting that senses when the environment is dark and again when it is light. Nevertheless, are flashy lights and a soothing voice that can tell us the temperature, turn on a light, or lock the doors what makes something smart? It is really the understanding of data and using patterns derived from it to positively influence our life that make the home smart.

Take, for example, a device like the early Nest Labs thermostat, where the homeowner would spin the dial to adjust the temperature. By doing so, they would teach the device their preferences, until it eventually operated autonomously without requiring user input. The system learns, thereby introducing the first level of actual “smarts.” However, would you want to be changing the batteries every year?

The Sensing Elements

Smart home decisions won’t be created simply by the presence or absence of user intervention. Additional contextual data will be required. In the case of smart homes — or other smart spaces — examining the data required for the desired application suggests the necessary sensing elements. For example, in a temperature control application, one might want to count people or use presence and/or identity detection. Sensing options include passive-infrared, direct/higher-resolution image sensing, low-resolution image sensing, or time of flight.

Temperature and humidity sensors are ripe for energy harvesting approaches in order to make their use much more convenient and more environmentally friendly — consumers will be happy to never have to replace or charge a battery.

Passive radio-frequency identification (RFID), which is a fast-growing sensing technology, by its nature uses energy harvesting — passive tags collect energy from a nearby RFID reader's interrogating radio waves. This means that they only use energy when a response is called for.

The Path of Innovation

Highly digital sensors will enable the data-gathering needed to create a smart home. (Photo courtesy of ams AG)

Starting with a particular technology can inspire all kinds of new uses. That approach happened with some areas in the smartphone space. For example, adding a GPS sensor to the already existing map applications. This has enabled navigation applications with crowd-sourced traffic updates, discount coupons being pushed at the phone user as they drive near a shopping mall, and even video games where you virtually chase invisible characters. While there is usually, at least one use case associated with a particular type of sensor, it is typically difficult to predict the many possibilities until the original app starts actually being used. It is more of a “build it and they will come” approach leading to more creative applications. And with this application approach, there are ever-new possibilities for energy harvesting. In Toulouse, France, for example, there is a project underway (Trottoir Électrique) — an energy harvesting sidewalk — where the mechanical energy of footsteps is converted to usable electrical energy.

Affordable, high-precision barometric pressure sensing could be used for detecting occupancy, or for indoor location purposes to determine if something is mounted at floor, wall, or ceiling height.

Microwave and time-of-flight sensing can detect motion and posture (laying down, sitting down, standing) and are ripe for energy harvesting since they are wall mounted. They can use differential temperature (inside vs outside the wall) to generate energy if the data-gathering intervals can be spread out to allow a storage capacitor enough time to recharge in order to be ready for the next sense or transmit cycle.

Electrical energy can be generated by footsteps on a sidewalk. (Image by VH-Studio/Shutterstock)

Where to Put the Sensors?

At first glance, one could assume that smart home sensors should simply be added to the appliance that makes use of them, such as temperature/humidity and open/close Hall-effect sensors in the refrigerator. But we may get better results by locating sensors in seemingly unrelated hosts.

Walls, windows, furniture, lights, and when rooms are occupied — people — are constants in our built space. Occupants already serve as one type of mobile sensor platform when they walk into a space carrying their smartphone or wearing their smart watch.

By applying energy harvesting techniques, wall materials could have sensors such as humidity or motion detection built into them. Lights, whether in a fixed mounting or in a bedside table lamp, are ideal platforms for a broad variety of sensors. Scattered everywhere and connected to power all the time, they can serve as hosts for HVAC temperature and humidity sensors that could move off the wall, and away from wires and batteries. The bill of material cost of the networking module would be shared with the connected light. Presence, motion, activity, identity, and ambient light represent a variety of disparate functions that will be integrated into tomorrow’s smart lighting platform.

Where We Are Now

A wide array of sensing nodes in the smart home, including smart appliances and lighting, will be hosted by built-in platforms.

While some of the sensing elements that enable all this are just arriving on the scene, it is important to note that we already have the most critical value-point enabler in place: the smartphone. Imagine the smart home to be a larger and more sensor-rich version of our smartphones: that application/big data platform will drive predictive smart home decision/response patterns in real time — just as our smartphone navigator happily pops up at 7:30 to ask if we’re going to drive to work. Prediction is at work already. We will see more improved apps and services and they will become more energy-independent by means of energy harvesting. Improvement will drive user satisfaction, and satisfied users turn over more data. More data is more opportunity to refine algorithms, and it increases the opportunity to monetize what is learned. The cycle of success and value feeds itself. Consumer adoption depends on simplicity and value. Smart home pioneers already appear to be learning the lessons, as anyone who has set up a ZigBee-based lighting control set will know. Plug it in, open the app, push the button on the bridge (one-finger security), and okay the addition of new lights into to the network.

All the key players in networking, communications, and data aggregation agree on the treasure trove of opportunities that the IoT and smart home represent, and they are collectively driving the standards, consortiums, and platform technologies that will ensure growing success.

The smart home will work and users will quickly accept the services as valuable. The key will be the deployment of sensors, which no one will really want to buy as stand-alone elements. What they will want to buy are the platforms that contain them, such as smart appliances, innovative smart lighting and other intelligent “things” that rely on integrated smart sensors. Build it, and the apps, value, ease of use, and reliable energy-sources will come.

This article was written Tom Griffiths, Senior Marketing Manager, Sensor Driven Lighting and Spectral Sensing, ams AG (Premstatten, Austria). For more information, contact Mr. Griffiths at This email address is being protected from spambots. You need JavaScript enabled to view it. or visit here .