As smart homes and wearables get more advanced, artificial intelligence is beginning to work in the background rather than on our screens. The industry is starting to move away from visible interfaces and towards technology that blends quietly into the spaces where we live and work. As Network World pointed out, this shift is leading to what many are calling ‘ambient intelligence’ – a way for devices to understand what’s happening around them without us needing to interact with them directly.
Instead of using apps or voice commands, systems pick up on motion, gestures, and patterns. They respond to us passively – by noticing where we are and what we’re doing. But while cameras have been the default tool for this kind of awareness, they come with some serious trade-offs. They raise privacy concerns, struggle in low light, have blind spots, and often require a lot of internet bandwidth. Cameras also make devices more expensive, especially when used in large numbers.
That’s why many researchers and engineers are exploring new ways to sense the world using tools we already have – like wi-fi, radar, and sound. Wireless technologies, paired with edge computing, make it possible to detect motion and presence in a space without collecting images or sound recordings. As smart devices become more common in homes, businesses, and the built environment, the idea is to make our surroundings smart too – so the intelligence isn’t locked into one device but is built into the space itself.
Using wi-fi to sense motion
One of the most promising areas is wi-fi sensing. It uses the same wireless signals that power internet connectivity to detect motion and activity – without adding new hardware. A Wi-Fi access point sends out radio waves which bounce off everything – walls, furniture, people, pets – and some of those reflections are picked up by receivers in other devices like smart bulbs or the router itself.
What the system captures is called Channel State Information (CSI), which shows how the signal changes as radio waves move through space. When someone or something moves, changes are measured. Over time, the system learns the “normal” state of the space and then notices when something shifts. Such small shifts can tell us a lot – whether someone is walking, standing, or even breathing.
The approach doesn’t need light to work, and it doesn’t care about walls or furniture. It’s private, passive, and already possible using devices many people already own. Recent studies have shown that with smart software, wi-fi systems can detect motion with over 90% accuracy in large networks of homes. Thus, millions of routers and bulbs can work together as a sensing layer.
Some systems are even smart enough to tell the difference between people and pets. They use details like walking speed and motion patterns to figure out whether that movement is a person, a dog, or a robotic vacuum. That level of awareness makes it possible to build smart homes that respond in useful ways.
Radar-based sensing at home
Another tool making its way into smart homes is radar. The basic idea is simple: send out a signal, and then measure how it bounces back. Radar has long been used in cars for parking and safety systems, and now similar technologies are being adapted for indoor use.
There are several types of radar tech used in these devices:
- Ultra-Wideband (UWB) sends out short, low-energy signals that make it easy to measure distances and detect motion. It works well indoors, even through walls, and is used for tasks like fall detection and respiration monitoring. UWB is known for being precise and energy efficient.
- Millimetre Wave (mmWave) operates at very high frequencies, which allows it to detect fine movements – like a hand gesture or someone breathing. It can also distinguish between multiple moving people. But mmWave sensors can be power-hungry, expensive, and struggle to work through walls, so they’re often used in small spaces, like cars or single rooms.
- Ultrasound uses high-frequency sound instead of radio waves. These are both too high and quiet for humans to notice but can be used to measure distance and detect movement. They’re cheap and low-power but don’t work as well if the air is moving or if objects are in the way. Devices like smart speakers and thermostats sometimes use ultrasound to know when someone’s nearby.
Creating smarter spaces, not just smarter devices
The goal of such systems is to create living spaces that adapt automatically based on what people are doing. Imagine lights that turn on as you walk through your house, heating that adjusts to where people are, or health monitors that track your breathing while you sleep – all without cameras or manual input.
When AI is paired with wireless sensing, these systems can work quietly in the background. They don’t need to be seen, touched, or spoken to. And because they don’t collect personal data like images or audio recordings, they’re easier to trust.
Still, challenges remain where devices must work in different homes, layouts, and habits. Sensors must be accurate and reliable, and the industry needs standards so that different devices and brands can talk to each other. A standard being developed now is IEEE 802.11bf, which aims to bring CSI-based sensing into the mainstream for wi-fi devices.
The next step: Combining signals
One of the most promising ideas is to combine different types of sensors into one system. For example, by merging wi-fi data with audio or temperature readings, AI can build a more complete picture of what’s happening. The approach – called multimodal sensing – lets systems learn not just when something is happening, but also why or what it means.
Voice assistants like Alexa are already experimenting with this idea. Features like “hunches” use behaviour patterns to take action automatically – like dimming the lights in the evening or adjusting the thermostat when you usually leave the room. The more signals these systems can use, the smarter they get.
But with more data comes more responsibility. Wearables with always-on microphones or cameras are becoming more common, and when they interact with smart home devices, it creates a deeper level of context – and greater concerns around privacy. As these systems grow more aware of our presence, habits, and movement, how that information is used matters more than ever.
Tech that works in the background
Passive wireless sensing offers promise in that it gives systems the context they need without watching or listening in. It’s efficient, scalable, and better aligned with privacy-first design.
Whether it’s for elderly care, energy-saving HVAC systems, or hands-free control in AR, such sensing methods could build the foundation for smarter homes and spaces. They don’t demand attention – they simply pay attention, in a way that’s not intrusive.
As homes get smarter, the smartest part may be the tech you never see.
(Photo by Ihor Saveliev)
See also: eSIM tech flaw exposes smartphones to serious hacking risks
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