How Smart Sensors Make Home Automation Work
Smart sensors are what make a home truly automatic. Without them, Homey can control your devices, but it can’t react to what’s happening around you. Sensors close that loop.
They tell Homey when someone enters a room, when a window opens, when air quality drops, or when water appears where it shouldn’t. From there, your home can respond on its own.
If you’re wondering where to start, or just want a clearer picture of what’s possible, here’s a look at the sensor types worth knowing about.
Security and Safety Sensors
These sensors keep Homey informed about what’s happening in and around your home. Most of the time, they stay quietly in the background and only become noticeable when something changes.
Contact Sensors (Door and Window)
Contact sensors track whether a door or window is open or closed. A small magnet attaches to the moving part, and the sensor body goes on the frame. When the two separate, Homey knows the door or window has opened.
They’re most commonly used to monitor entry points or to avoid heating a room with an open window. A Flow can turn off your smart heater the moment a window opens, so you’re not heating the outdoors.
Motion Sensor (PIR)
PIR motion sensors, short for passive infrared, detect heat signatures moving across their field of view. They’re fast and reliable for detecting movement in hallways, driveways, or near entry points, but they’re not good at detecting someone who stays still. If you sit still long enough, they’ll assume the room is empty.
You can use them to trigger lighting in areas where people are always moving, or to send an alert when someone approaches your front door while you’re away.
Presence Sensors (mmWave)
Presence sensors solve the main limitation of motion sensors. mmWave radar can detect subtle movements, such as a person breathing or shifting in a chair, so Homey always knows whether a room is truly occupied.
This makes them ideal for spaces where you spend time sitting still, like an office or living room. A Flow can keep your desk lamp or radiator on as long as the sensor detects you, and shut everything off only when you actually leave.
Vibration and Tilt Sensors
These sensors use an internal accelerometer to detect impacts or changes in angle. They can detect movements that a contact sensor would miss entirely.
Attach one to a washing machine to get a notification when the cycle finishes, or place one on a valuable item to get an alert if someone tries to move it.
Sound and Noise Sensors
Sound sensors monitor ambient noise levels and can distinguish between background noise and sudden, sharp sounds. They allow Homey to respond to sound, even in rooms without a camera.
A common use is detecting a smoke alarm from a non-smart detector, or getting a notification when the tumble dryer finishes its cycle.
Water Leak Detectors
Water leak detectors sit flat on the floor and trigger when moisture touches their contact points. They’re small, inexpensive, and can prevent serious damage if placed in the right spots.
Put one under the sink, behind the washing machine, or near the water heater. Pair it with a smart water valve in Homey, and a Flow can shut off your main water supply automatically the second a leak is detected.
Smoke and Carbon Monoxide Detectors
Smart smoke and CO detectors do everything a standard alarm does, but they also talk to Homey. That means an alarm can trigger more than just a beep. It can trigger actions across your whole home. For example, a Flow can switch every light in the house to bright red and unlock all smart locks the moment smoke is detected, giving everyone a clear signal to leave.
Radon and Gas Sensors
These sensors monitor for threats you can’t see or smell. Radon sensors track long-term exposure levels in your home, while gas detectors watch for methane or propane leaks near stoves or boilers in real time. A Flow can alert you through your smart speakers or shut off a smart gas valve as soon as dangerous levels are detected.
Comfort and Environmental Sensors
These sensors monitor the conditions inside your home, so Homey can keep things comfortable and healthy without constant manual input.
Temperature and Humidity Sensors
Temperature and humidity sensors are the backbone of automated climate control. They’re small, battery-powered, and easy to place where they matter most, which makes them far more flexible than a single wall thermostat.
Place them in rooms that tend to run hot or cold to give Homey a more accurate picture of your home’s climate. Many devices also report temperature and humidity alongside their main function.
Air Quality Monitors and VOC Sensors
Air quality monitors track CO2, particulate matter, volatile organic compounds, and other pollutants that affect how your home feels and how well you sleep.
Modern homes are often well-insulated but not always well-ventilated. That makes these sensors especially useful. A Flow can switch your air purifier to high speed when a pollutant spike is detected, or open a smart window when CO2 rises above a set threshold.
Light and UV Sensors
Light sensors measure ambient brightness in lux, while UV sensors track the intensity of sunlight. Together, they give Homey the data it needs to manage blinds and outdoor lighting based on the light outside, not just the time of day.
A Flow can lower your living room shades during peak sun hours to reduce heat buildup, or trigger your patio awning when UV levels climb too high.
Wind and Rain Sensors
Wind and rain sensors act as a small weather station for your home. They detect when rain starts or wind speeds begin to rise, so outdoor automations can respond before the weather becomes a problem.
Use them to bring in your awning when a storm picks up, pause your garden sprinklers during rain, or send your robot mower back to its dock before it gets soaked.
Soil Moisture Sensors
Soil moisture sensors measure whether your soil is dry, damp, or saturated using electrical conductivity. They make watering more precise and help prevent both underwatering and overwatering.
Place them in flower beds or indoor pots and connect them to a smart irrigation valve in Homey. A Flow can start watering only when the soil actually needs it.
Energy and Utility Sensors
These sensors track how your home uses electricity, water, and gas, giving Homey the data it needs to reduce waste and spot unusual patterns.
Smart Energy Monitors
Smart energy monitors attach to your electrical panel or plug into outlets to track power consumption in real time. They show you which appliances are using the most energy and when, so you can shift heavy tasks to cheaper or greener hours.
Homey supports several ways to monitor energy use. The Homey Energy Dongle connects directly to your utility meter’s P1 port for whole-home readings. For meters in basements or utility rooms without Wi-Fi or a power outlet nearby, IOmeter offers a wireless alternative that sends live data to Homey every few seconds.
Smart Water Meters
Smart water meters monitor flow rate and total volume through your main pipes. They can detect everything from a running tap to a hidden pinhole leak, and give you a much clearer picture of your daily water use.
A Flow can automatically shut off your main water valve if the meter detects continuous flow for more than 30 minutes, catching a leak before it becomes a bigger problem.
Smart Gas Meters
Smart gas meters track the volume of gas consumed by your heating and cooking appliances. They help you connect heating costs to outdoor temperatures and spot unusual consumption patterns more quickly. A Flow can alert you if gas usage occurs when your heating and stove should be completely off.
Solar and Battery Monitors
Solar and battery monitors track how much energy your panels are producing and how much is stored in your battery system. This data usually comes directly from your inverter or battery through a local or cloud integration.
With that data in Homey, a Flow can trigger your washing machine or EV charger only when your panels are producing more than your home is currently using, helping you make better use of your own energy.
Smart Sensors in Homey
Homey connects all these sensor types into a single system. It speaks Zigbee, Z-Wave, Wi-Fi, Bluetooth, 433 MHz, Thread, and Matter, so you can mix and match brands without needing separate hubs or apps.
The real power comes from combining sensors in Flows and Advanced Flows. A presence sensor and a light sensor together can dim your lights and adjust your thermostat the moment you settle into a room. A water leak detector paired with a smart valve can protect your home while you’re away.
On their own, sensors just report what’s happening. In Homey, they give your automations context.
