Sensors in our homes are nothing new. House alarms have relied on them since the first electromagnetic systems became available more than a century ago.

However, with the growth of the smart home, sensors have become more prevalent. These days, you can find a plethora of detectors covering a broad range of uses and functions.

In fact, there are so many available, it can be difficult to know which ones are worth buying. But don't worry, as always, MakeUseOf has you covered.

Here are six sensors every smart home should have.

1. Motion Sensor

When you think of motion sensors, your mind probably drifts towards home security. After all, it's the usage situation in which we're most familiar with them.

And of course, you'd be right. All the latest smart alarms rely on them. The premise is simple, if the sensors detect unauthorized motion inside your property, the exterior siren will sound.

But thanks to the connected smart home and the Internet of Things, motion sensors have many more uses.

samsung motion sensor

For example, why not hook one up to your smart lights? You can make the lights immediately fire up whenever you enter a room between two predefined times. You can even take it a step further: perhaps you want the bathroom light to illuminate in all its glory between 6 PM and 11 PM, but only emit a soft glow between 11 AM and dawn.

Motion sensors are also an excellent way to keep a "virtual" eye on dangerous areas. For instance, you could receive an alert every time a child or pet ventures need your swimming pool.

One of the best models to consider is the Samsung SmartThings Motion Sensor, which costs $39.99.

2. Water Sensor

Did you know flood damage costs American insurance companies more than $10 billion per year? Of course, some of that damage comes from natural causes, but a significant majority derives from leaks, breakages, and user negligence.

Nobody wants to deal with insurance companies. Unless you're hypervigilant about recording all your receipts and keeping your photographs up to date, you are almost guaranteed to end up out-of-pocket.

Wouldn't it be easier to spend a few dollars on some water sensors and nip the problem in the bud?

The Fibaro Flood Sensor costs $69.99. It works with Apple HomeKit and Z-Wave. Not only will it alert you if a leak is detected, but can also inform you if the device has been inadvertently moved or tampered with. Best of all, it can even shut off your water supply in the event of a major leak, thus giving you peace of mind if you're away from home.

If $69.99 is too much, check out the $29.99 Lowe's Utilitech White Flood Sensor [No Longer Available] instead, which works with Iris systems.

3. Doorbell Sensor

The doorbell sensor is a twist on the motion sensor. Rather than just alerting you to movement and sounding an exterior alarm, a doorbell sensor can start playing a live video feed from your doorstep when someone is there, even if the person hasn't pressed the buzzer yet.

It's perfect for people who live alone and who might feel threatened by an unknown caller in the evening. It also lets you steer clear of unsolicited sales people and other door-to-door pesterers. You can think of it as a peep hole for the 21st century.

ring smart doorbell

Any high-quality smart doorbell system should come with a built-in video feature, but you can also buy standalone non-bell systems such as Ring---though is Ring making your home less safe? It offers two-way audio, a motion detector, and night vision. The device costs $179.

4. Temperature Sensor

Why would anyone need a temperature sensor? You don't need a gadget to tell you it's hot outside, do you? Perhaps not. But you do need something to tell your other smart home devices that it's hot outside.

What exactly do I mean? Well, you can split temperature sensors into two broad uses: inside the home and outside the home. Sensors outside the home can help control your garden-based smart devices. For example, if it's been above 25 degrees for the last two days, you can get your smart sprinklers to turn on.

Alternatively, inside the home, a temperature sensor can help get you through the summer. It can make your air conditioning turn on 15 minutes before you get home from work if it's too hot, or get your smart thermostat to crank up 30 minutes before your alarm goes off on a cold morning.

Interested? Check out the HomeSeer HSM200 or the Elgato Eve.

5. Light Sensor

Light sensors can both save you money and improve your home's security.

Accidentally leaving your lights on is nothing new. And sure, leaving on one light once or twice a week if you live alone isn't going to break the bank. But if you've got a partner and a couple of kids, you could be leaving several lights on when you all leave home in the morning.

Over the course of a decade, it's a lot of wasted money.

Light sensors can turn off the lights in your home once dawn breaks, then turn them on again when dusk arrives. They will save you money and can also make it seem like people are at home if you are traveling. It's a win-win.

6. Weather Sensors

Like temperature sensors, weather sensors can do much more than just tell you whether you'll need your umbrella later.

Plug them into your smart home, and they can connect to several other sensors and automate certain tasks.

For example, you could pair them with your smart alarm. If rain is forecast, you can get alerts telling you which windows are open. Or why not hook it up to a smart mirror in your bathroom? If there's a high risk of UV rays during the day, your mirror will be able to remind you to wear sun cream.

netatmo weather sensors

There are lots of weather sensors and stations to choose from. Perhaps the most well-known is Netatmo. It can measure temperature, humidity, air quality, and even nearby sound levels. You can pick up the entry-level kit for $131 on Amazon.

For more ways to keep updated on the current conditions and forecast, take a look at these awesome weather stations.

The Sensors of Tomorrow

Of course, there are lots more sensors you can add to this list (if you don't already have a fire or carbon monoxide detector installed in your home, you should definitely get one -- whether as a smart device or not) . But before we conclude, let's take a step back and look at the future of sensors. What can we expect to see in a few years' time?

Hopefully, the answer will be synthetic sensors.

A synthetic sensor will be able to plug into an electrical socket and control everything in the room. A prototype, which was unveiled at the ACM CHI conference in May 2017, has 10 embedded sensors that monitor everything from sound and humidity to electromagnetic noise and motion.

If successful, synthetic sensors will prove to be a much cheaper and easier way of turning your dumb home into a connected abode.

Do You Use Sensors?

So, we've told you which are the six most useful sensors that any smart home enthusiast should install. Do you agree with our choices?

For more regarding smart home and security in particular, check out how to stay safe with your smart home gadgets. And if you're looking more products to improve your smart home experience, try smart plugs next. See how smart plugs can make your life easier and safer.