The best smart sensors transform a dumb home into a smart one: you'll find your smart home is much more intelligent if it knows what's going on inside it. With the right sensors, your property will be more secure and safer, and these clever gizmos can fit all kinds of uses.
Buying the best smart sensors doesn't mean your home becomes a sentient robot, but it does give you more information – whether windows are opened or closed, how clear the air is, whether there's movement outside, and so on.
Motions sensors can work with smart lights or smart heating systems to swing into action when you get back home, for example, while you can also combine sensors with smart locks and smart security cameras too. There are plenty of possibilities open to you.
The best smart sensors usually give you plenty of automations to play around with, enabling you to build customised routines that suit your own ecosystem. If you want to save some money, you can opt for simpler models that just offer phone alerts.
At this point it's worth emphasising that many sensors won't work in isolation, and will usually need a separate hub to pass on information. This might need to be compatible with the Zigbee or Z-Wave protocols, or offer support for Bluetooth or Wi-Fi, so double-check the specs before purchasing.
So, whether you're after the best smart motion sensors in particular, or wanting to install something else, here are our top picks for the best options in 2021. Get these installed now, and your smart home is instantly upgraded.
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Our pick of the top smart home security sensors
You could accuse the Minut of over-egging its pudding somewhat, because this is a compact device that senses a whole lot of different things. It seems to be designed for landlords to put in rental properties, because noise sensing is one of its key functions: not only picking up the decibels currently pumping out, so you can tell if someone's turning those speakers up a little too loud or partying illegally in your Airbnb, but sensing the sound of smoke alarms and passing that alert onto your phone.
It'll also keep an eye on temperature, it includes a motion sensing PIR which can sound a siren should you arm it to do so, and there's a tamper detector to sense if some cheeky occupant has prised the innocuous disc off the ceiling. There's also mould detection, which could be very vital depending on where you place it; if you're using it for yourself to ensure the air in the nursery is sufficiently clean, we'd probably turn the siren off.
The Minut is surprisingly handy, and should give you a solid six months on a single charge. The only real downside is that it's only chargeable by USB; while you could presumably wire up some way to have it charge constantly, if you're running a rental property it would likely be more useful if you could swap in a set of AA batteries instead.
It's slim, but this certainly isn't the narrowest of door and window sensors. It is, though, one of the more capable out there. The SmartThings Multipurpose Sensor gives you two key pieces of information: whether the thing you've stuck it to is open or closed, be that a door, window or even a drawer full of precious things, and what the temperature is in the vicinity.
You can get an alert sent to your phone when any of its conditions are met, or when the temperature hits a certain level, but that's really only half of the story: it's the automations, the linking, the intricate combinations of technology that you can put together which really seal the deal.
While it does run on Zigbee 3, meaning you should be able to convince the SmartThings Multipurpose Sensor to connect with Zigbee hubs like the Echo Plus or second-gen Echo Show, the fact is that you'll get the best results if you're connecting it to a SmartThings Hub. This does add extra expense, but it may be a small price to pay if you're looking to expand from one window sensor into many, or add some of Samsung's other sensors to the mix - there's a motion sensor and a water leak sensor in the range, as well as the Arrival Sensor below and a host of compatible kit from third parties.
Door and window sensors are a perennial favourite among home security folk, since they're less likely to be triggered by wandering pets or billowing curtains. They usually come in two parts – one that attaches to the door or window frame, and the other that attaches to the door or window itself.
When the door or window is closed, the circuit between the two parts of the sensor is complete and so is marked as 'closed' – but as soon as a door or window is opened, the circuit is 'broken', which triggers an alert.
The Hive Window or Door Sensor is part of British Gas' popular Hive smart home system, which also includes the Hive Smart Thermostat and other goodies. Like most of the other sensors here is relies on a central hub to work (rather than connecting to your smartphone or tablet individually) so you’ll need to factor in these additional costs at purchase time.
Of course, as most of us live in homes with multiple doors and windows you may need to buy several Hive Window or Door Sensors to cover your living space – and British Gas sells them in both packs of three and five, as well as as individually, so you’re covered. A Hive Window or Door Sensor is also included in the Hive Starter Pack.
In practice, however, you probably only need to buy door or window sensors for the most vulnerable doors and windows, with wireless motion sensors (see below) covering other spaces.
Fixing the Window or Door Sensor requires no special skills – you just attach pop in a lithium battery, make sure the sensor can be picked up by your smartphone or tablet, choose a location name ('front door', for example) and then attach each part of the sensor to the relevant part of the door or window frame using the self-adhesive pads.
From then on, every time the door or windows is opened, you'll receive an alert telling you what's happened. You can also use the Hive smartphone app to quickly check all the doors and windows fitted with a Window or Door Sensor are closed before you leave home.
It's a simple system that works well, and definitely one of the best sensors that we've come across. Note that you don't have to be a British Gas customer to use Hive kit.
Let's get the obvious bit out of the way first: this (technically) only works with a Philips Hue smart light set, unless you can convince it to connect to another Zigbee hub, so it's only going to appeal to a certain subsection of buyers. That said, it works very well, doesn't cost much, and can be placed just about anywhere thanks to two AAA batteries powering it.
If you need to, you can combine two or more of these sensors together, to turn the lights on and off as you walk up the stairs for example. You will need a Hue Bridge plugged into your router, but that should've come with your lights.
What makes the Philips Hue Smart Motion Sensor really impressive is not what it is but what you can do with it – the Hue app for smartphones lets you set up all kinds of routines and actions, so you can save energy when there's no one in the room and turn the lights on automatically whenever someone is.
Another home security favourite, motion sensors use infra-red technology to detect movement within a room or space, triggering an alert when it is detected. At one time motion detectors had a reputation for creating false alarms, although technological improvements now make that less likely. Most motion sensors are adjustable too, so if you do have a false alarm you can adjust its sensitivity so it doesn't trigger next time.
As you'd expect, the British Gas Hive Motion Sensor does send a notification to your smartphone or tablet every time it detects movement, just as it's supposed to. However you will need to partner it with a Hive Hub for it to work – so it's best fitted as part of a whole Hive Smart Home system (you don't need to be a British Gas customer for this though).
The Hive Motion Sensor itself is easy to set up – simply pop in a battery, register the device and its location using the Hive app, then place it in a suitable location, either using the sticky pads on the back of the device itself or by placing it free-standing on an object such as sideboard or table.
Like most Smart Home systems you can use the Hive Motion Sensor to trigger further actions – such as automatically switching on a light when it detects movement, for example.
You can also track movements picks up by the sensor over time. That can be handy if you're keeping a virtual eye on a elderly relative, for example, and want to check that they're active without actually 'spying' on them.
This square-shaped motion sensor is part of Eve Systems' smart home range, which is aimed at Apple users, and as such it relies heavily on Apple's HomeKit. While the Eve Motion can send alerts to you when you're at home using Bluetooth, when you're away it relies on the 4th-generation Apple TV (or an Apple HomePod) to send alerts outside the home – and that might be a deal breaker for some.
Having said that, the Eve Motion is a powerful piece of kit. It's easy to set up and use, with the accompanying Eve app for iOS 10.3 or later enabling you to use the Eve Motion to set a complex chain of events in motion (automatically switching on lights and heating with other compatible devices, perhaps, when you get home).
The Eve Motion also has a longer viewing distance than the Hive Motion Sensor (9m vs 6m) and a slightly wider field of view (120 degrees vs 110). We also prefer its more elegant design.
If you need water and leaks detecting, then get the D-Link DCH-S161 on the job: it's simple but effective, and thanks to a cable that stretches for 1.8 metres (that's nearly 6 feet), you've got a lot of flexibility when it comes to choosing where to put it.
Not only will this clever little gizmo ping your phone when it senses water, it will also emit a 90dB siren sound to make sure you don't miss the warning. For that extra bit of freedom from wires, it's powered by two AA batteries which D-Link says should last you for a year and a half.
Operating via your home's Wi-Fi, the D-Link DCH-S161 is easy to mount on the wall if needed, and it works nicely with the Google Assistant too, so you can keep tabs on it through your smart speakers. Know about a water problem as soon as it happens.
If you're looking to keep an eye – literally – on the goings-on in and around your home, then the Fibaro Motion Sensor could be the best smart sensor for you. Powered by a CR032 battery and totally wireless, the 5cm semi-spherical 'eyeball' sensor can be placed almost anywhere.
It offers four main functions: it can detect movement, temperature, light and vibration, and then alert you either via the free Fibaro app or by flashing its multi-coloured 'iris' (with the colour of the iris serving another purpose as a temperature indicator). Innovative then, but a bit weird…
There's more to the Fibaro Motion Sensor than that, though: it can automatically fire up your smart home lighting, or switch it down or off when it detects movement, and can also be set to switch lights on or off automatically by detecting the amount of ambient light in a room.
You can also include it in any smart home 'scenes' you’ve created – so you could have it automatically set the lights to come on when at certain times or day or night, for example. The Fibaro Motion Sensor is available in two different versions – one for Z-Wave compatible systems (including Amazon Echo and Samsung SmartThings) and there's also a HomeKit version for Apple fans.
The Arrival Sensor, also listed in some places as the SmartThings Presence Sensor, is one of the smarter smart home objects for a very simple reason: resembling the Tile's wireless key finder, it's a Zigbee-enabled key fob that you can attach to or place inside a loved one's belongings and then have it trigger an alert every time they either arrive at or leave home.
On the face of it, this sounds slightly stalkerish, but the Arrival Sensor is also a little cleverer than that.
For one thing, the Arrival Sensor is part of Samsung’s SmartThings smart home range, which includes things like smart plugs and motion sensors, so it can be used to trigger custom events – such as automatically switching the lights on when your partner or other members of your household nears home.
It's also handy for keeping tabs on pets or elderly relatives who have a tendency to wander from home. If you're after one of the best smart home sensors of 2020, get this one down on your shortlist.
The compact Eve Room sensor works with or without a power supply attached (you get six weeks of use between charges), keeping an eye on the air quality, temperature and humidity inside whatever room you decide to put it in.
Whether you want to make sure your child's bedroom is clean and fresh, or you want to see what kind of a change cooking dinner makes to the internal air quality, the Eve Room sensor can keep you updated in real time. It's compatible with the Apple HomeKit platform, giving you plenty of flexibility in terms of how to use it.
The device actually connects to your phone via Bluetooth, so there's no danger of you losing the functionality of the device if the Wi-Fi goes down. If you're ready to start obsessing about the air quality inside your home, then get this.
No one wants to discover parts of their home frozen up or covered in water, and the Honeywell W1 Wi-Fi Water Leak and Freeze Detector can give you a useful heads up about water leaks, extreme temperatures, and issues with humidity.
There's a 1.2-metre cable to wrap around pipes that you think might be vulnerable, and all you need besides that is a Wi-Fi connection and the Honeywell app on your phone. It couldn't be much easier to set up.
If a problem is spotted then the 100 decibel siren will certainly let you know about it. It's battery powered too, so you don't need to worry about finding a mains socket, and you can check up on the device's reading whenever you like.