Motion, contact, and light sensors are the most commonly used sensors for home automations in my house. With these sensors, you can make a wide variety of automations. But there are so many different manufacturers, protocols, and price points that it can be hard to choose which devices to buy and use.

When setting up automations, check out these set of best practices to avoid common mistakes. It boils down to having automations that do the same thing as you (and your guests) would do before the automation existed. For instance, turn on the light when entering the bedroom, but not if it’s filled with sunlight.

Sensor speed

Before we dive in, I want to make a note about sensor speed. For lighting automations, speed is usually the most important factor to consider. When entering a dark room, most people instinctively reach for the light switch. It’s in their muscle memory.

When a lighting automation is slow, that muscle memory triggers, and they reach for the switch. Just before pressing the switch, the automation turned on the light, so they end up turning the light switch off.

When the lighting automation is super-fast, that muscle memory never triggered in the first place and the automation feels magical.

When using Samsung SmartThings hub, make sure to run all your lighting automations in the Smart Lighting SmartApp. For all involved devices (usually switches/bulbs + sensors) make sure they use local device handlers. Then the automation will execute locally without accessing the internet. The speed difference from local to internet execution is significant.

I’m not affiliated with any manufacturer or reseller. I’ve tried enough sensors to give me an idea about which ones work better than others for my needs. You might have a different experience or know of sensors that I haven’t tried. In that case, please share that in the comments below.

Motion sensors

The most important factors to consider when buying a motion sensor are speed, battery life, and design.

Zigbee vs. Z-Wave

Of all the sensors I’ve tried, the Zigbee ones are the fastest. I don't know why that is, but others have experienced the same thing. So, for automations where speed is important such as turning lights on when entering a room, I would go with a Zigbee device every single time. The difference in speed is very noticeable.

For automations where speed isn’t as important, such as for detecting when motion has stopped, then battery life and design matters more.

Placements

Motion sensors look a little bit like small spy cams, so I try to make them as invisible as I can to not freak out my guests. Especially the ones placed in the bathrooms. Good places to but them are corners just below the ceiling.

For super-fast detection when someone enters a room, place the motion sensor on the ceiling close to the wall directly above the door pointing downwards.

Which one to get

If I could have only a single type of motion sensor, I would choose the Samsung SmartThings Motion Sensor. It magnetically attaches to its base and the battery life is superb.

Contact sensors

Also known as door/window sensors. This type of sensor consists of 2 pieces – a magnet and a sensor. When the magnet moves away from the sensor, it’s in its “open” state and when they are together it’s “closed”. Again speed, battery life, and design are the most important features to consider.

Zigbee vs. Z-Wave

Just like with the motion sensor, speed can be the deciding factor. If opening a door should trigger the lights to come on, then Zigbee is the way to go. For everything else, battery life and design are more important. For me, that means I use Zigbee devices for doors and Z-Wave devices with larger batteries for windows.

Placements

For doors, place them on the side of the door that is away from the main areas in the house. For instance, put them inside the closet where nobody can see them when closed. Put them on the bedroom side of the door instead of the hallway side.

For windows, place them where they are hardest to see. You can’t really hide them.

Color

Some manufacturers make different colored sensors. Try to match the color of the sensor with that of where you put them. This makes them more invisible.

Which one to get

For doors, I use the Visonic MCT-340 E which is super-fast and relatively small compared to most other contact sensors. For windows or other places where speed isn’t an issue and battery life matters more, the NEO Z-Wave sensor is great. My shower door has a brown metal frame, so for that I use the slightly bigger Z-Wave Rare Earth Magnet sensor which comes in brown.

Light sensors

With a light or illuminance sensor, we can adjust our automation based on the amount of light present in the room. That way we can avoid turning on the lights when the room is already filled with sunlight. Or we can adjust the dimming level of a light switch to the amount of light presently in the room.

Zigbee vs. Z-Wave

For me, it usually comes down to speed. In this case, it probably doesn’t matter since light measurement isn’t done in real-time but usually captured every 1-5 minutes depending on the sensor. So, battery life and design are more important to consider than speed.

Usually, light sensors don’t come as standalone sensors, but as part of multi-sensors that also does motion and temperature sensing. At the time of writing, I have yet to find a light sensor that also has a super-fast motion sensor.

Placements

You could place a light sensor in each room, but that would most likely be overkill. Unless you already have a multi-sensor in the rooms with light sensing capabilities. Instead, what I’ve done is to place one sensor on each side of the house. So, no matter what room I automate, I know the amount of light coming to the windows on that side of the house.

Place them in the window close to the glass so curtains don’t get in between them and the window itself.

Which one to get

I use the Dome Z-Wave Motion/Light sensor because it is relatively cheap and gives consistent light level readings. It’s important to notice that I don’t use the motion sensor in this device at all. It’s too slow and it doesn’t allow me to place it in the best position for light sensing.

When using SmartThings Hub, use the Z-Wave Temp/Light Sensor device handler for this sensor. It allows it to run locally.

I hope you found this helpful. Remember to check out more home automation ideas and the best practices.

Here are a bunch of home automation ideas for your inspiration. These are examples of automation rules that have worked well for my family. They might work well for yours too.

The ideas are technology agnostic and describe the concept rather than the exact implementation. They should work with just about any home automation system and they all adhere to the home automation best practices.

Let’s dig in.

Modes

Most home automation systems have the notion of modes. Typically, the names of these modes are Home, Away and Night, but there can be variations and some system let you add additional modes. You can use these modes as conditions for the home automation rules. For example, when the mode is set to Night, turn on lights on low dim in the kitchen when motion is detected.

When set properly, modes are useful in many automations.

Night

• Manually set house in Night mode
• Automatic detection

Set the mode to Night when clicking a physical button or switch. A voice assistant could also trigger it when you say “goodnight”. Physical buttons are often easier to use than a voice assistant and works when offline.

Setting Night mode could trigger the following events:

• Turn off lights in the kitchen, living room and elsewhere
• Turn off media – music, TV etc.
• Lock the exterior doors if unlocked
• Close the garage door if open
• Arm the alarm system

Home

There are two scenarios for when you want to trigger Home mode. The first is when you get out of bed in the morning and the second is when you come home to an empty house after having been away.

In the morning, press a physical button or switch or say “good morning” to your voice assistant. The button/switch could be the same one that put the house into Night mode.

After being away, unlocking the front door, opening the garage door or simply the detection of motion can put the house back in Home mode automatically.

Setting Home mode could trigger the following events:

• Turn on lights if dark inside
• Play music
• Turn on thermostat to cool or heat the house
• Turn on indoor holiday decorations
• Dock the robot vacuum

Away

This mode should be set when everybody leaves the house, and nobody is home. Saying “goodbye” to the voice assistant is one way to set it, but it should really happen automatically instead. That way you never forget it and don’t have to worry about it.

Automatic detection could happen this way:

• House is in Home mode
• No motion detected in the house for 10 minutes
• All phones or presence sensors report they are not home
• No one is taking a nap in the house

Detecting someone napping during the daytime can be hard. We use white noise machines in the kids’ room for when they nap, so we use a power meter to detect when it’s on. When on, the house doesn’t go into Away mode. If you don’t use a white noise machine, a night/salt/lava lamp or similar will work just as well.

If you wish to know when the mode changes between Home and Away, send a push notification to your phone if your system supports it.

Setting Away mode could trigger the following events:

• Lock all exterior doors if unlocked
• Close garage door if left open
• Turn off all lights, fans, and appliances in the house
• Start the robot vacuum
• Put the thermostat in “eco” mode
• Between sunset and midnight, turn on away-lights
• Arm the alarm system

Bathroom

This is for bathrooms that have both a tub or shower and a toilet.

Lights

• Turn on lights when someone enters
• Turn off lights when everyone leaves

Fan

• Turn on fan when door closes
• Turn off fan after 15 minutes

Use a motion sensor to turn on the lights when someone enters the bathroom. Use a door sensor to detect when the door is closed. When closed, the lights must not turn off automatically. That ensures that the lights don’t turn off while you’re in the shower or taking your time on the toilet.

The fan turns on automatically when the door closes and turns off again after 15 minutes.

When in Night mode, the lights should only come on at a low dim.

Shower door

This is if you have a dedicated light just for the shower.

• Turn on shower lights and bathroom fan when shower door opens
• When shower lights are on, don’t turn off any other bathroom lights

If you have a glass shower door, add a door sensor too it. When the door opens, turn on the shower lights and fan. Turn off lights and fan after 15 minutes.

Garage

Whether you park your car in the garage or use it for storage or workspace, here are some automations that apply to all scenarios.

Lights

• Turn on when someone enters
• Turn off after the last person leaves

Add one or more motion sensors to cover the whole garage. When motion is detected, turn on the lights. When no motion was detected for 1 minute, turn off the lights. Depending on the location and speed of the motion sensors, consider adding a door sensor to the internal door that triggers the lights upon opening.

Door

• When going to bed, close garage door if open
• When leaving the house, close garage door if open

When the home automation system goes into Night or Away mode, check if the garage door is open and then close it.

Hallway closet

Some closets don’t have any lights or power outlets on the inside. The closest light source could be a ceiling light on the outside. Then we’ll use that in our automation.

Lights

• When in Home mode
• Turn lights on when door opens
• Turn lights off when door closes

Add a door sensor that triggers the light to turn on and off when the door opens and closes, respectively. If the light is located outside the closet, you may want to check if it was on before opening the door, so the automation doesn’t turn it off when the door closes.

“Dumb” battery powered LED lights with basic motion sensing capabilities are also useful. We use them in some closets that have no other light source or power outlet.

Walk-in closet

Typically, a small room full of clothes and a ceiling light. The door is probably left open all the time.

Lights

• Turn on when someone enters
• Turn off after the last person leaves

Add a motion sensor above the door pointing slightly downwards so it covers the whole closet as well as the door entrance. When motion is detected, turn on the lights. When no motion was detected for 1 minute, turn off the lights.

When in Night mode, turn on the lights at a lower dim setting to not be blinded by the bright light.

Kids rooms

Our kids can’t reach the light switch in their rooms, so automated lighting was very important for us. Otherwise they would keep asking us to come turn on the lights for them.

Lights

• When in Home mode
• Turn on when someone enters
• Turn off after the last person leaves
• Turn off lights when white noise machine starts (nap/bedtime begins)
• Turn on lights at low dim setting when white noise machine is off
• Then slowly brighten lights over a 5-minute period

Blinds

• Close blinds when white noise machine starts (nap/bedtime begins)
• Open blinds 10 minutes after white noise machine is off

Motion sensor triggers lights on/off when someone enters and leaves the room. A power meter connected to the white noise machine triggers the lights off when turned on. Turning off the white noise machine should very slowly start to brighten the ceiling lights from the lowest dim setting.

Use an illumination (light) sensor to detect how light it is in the room before turning on the light. There is no reason to turn on lights in a room full of sunlight.

Master bedroom

This room is notorious for being hard to automate. The reason is that there are so many usage scenarios that it is hard to identify patterns automatically. We tried automating the lights, but there would be times when that would be annoying. We made modifications and kept iterating until we came up with a simple rule that works:

• When in Home mode
• And it is dark outside (no light coming in)
• Turn on master bathroom lights when someone enters bedroom

Most of the time we enter the bedroom, it is to pass through into the master bathroom, which is also where the walk-in closet is. So, turning on the bathroom lights does light up the bedroom a bit, so we don’t have to walk in the dark.

Outside

Landscape lights are pretty, and they help you see the driveway when coming home at night.

Lights

• Turn on at sunset
• Turn off at sunrise
• Turn on additional driveway lights when car pulling in
• Turn on holiday lights at 30-60 minutes before sunset

You can buy “dumb” light switches with sunset/sunrise capability, but they are no fun and if you have multiple lights, then you can’t fully coordinate them.

Hook up a motion sensor to trigger the driveway lights to guide the car in. Turn back off after 5 minutes of no motion detected.

Car

These days, the smart home includes the car.

Door lock

• Unlock front door when coming home
• Lock front door when leaving

Place a presence sensor somewhere in your car(s) and automatically unlock the front door when you arrive home. Unless the garage door is open/opening. If the garage door is open/opening then you are probably going to enter the house through the garage, so no need to unlock the door.

Miscellaneous

Here are some additional automations that could apply to multiple rooms or the whole house.

Windows

• When a window has been open for more than 1 minute, turn thermostat off
• When closing all windows, turn thermostat back on

Add window sensors (same as door sensor) to all windows.

Night lights

• Turn on lights when motion is detected

In the kitchen, living room and elsewhere, turn on lights at a very low dim setting when motion is detected in Night mode. Make sure it’s dim enough that it won’t wake up anyone sleeping in their rooms with the door open.

Door lock notifications

• Send notification when non-members of the household come and go

Get a push notification when anyone that has their own code to your smart lock uses it. That helps you keep track of how long the house cleaners spent cleaning or if your parents came to drop that thing of you asked them to while you were at work.