HomeReviewsSomeone Opened the Door: SwitchBot Contact Sensor Review

Someone Opened the Door: SwitchBot Contact Sensor Review

Not long ago we introduced you to SwitchBot, a company that has a bunch of smart devices that work well and are very affordable. We looked at the Switchbot Bot, Curtain, Solar Panel, Hub Mini, Meter and Remote and this time around the company hooked us up with a bunch of new products, one of which being their new Contact Sensor. Unlike other smart sensors, this one reacts to a magnetic trigger on both side, so it works best installed on the entry door or windows.

Sense when your door or window open and close. Two components stand in line With a detection range of up to 5m, 90° horizontally, and 55° vertically. The magnet part needs to be aligned with the bottom of its main body, and the distance between the two components should be less than 30mm.

The SwitchBot Contact Sensor is a Bluetooth device, just like the SwitchBot Motion Sensor, but, while this type of devices are not the best for home automations, they can work without a hub and this one takes full advantage of the SwitchBot API when paired with the SwitchBot Hub. If you mix the two together you get a lot of features from a seemingly simple device.

Features and specifications

  • Motion range up to almost 30 feet detection distance within 110° horizontally and 55° vertically
  • Magnet sensor range less than 30mm
  • Customizable sensitivity
  • Built-in light level sensor
  • Long life (up to three years) using two AAA batteries
  • Magnetic sensor, adhesive and mounting screws included
  • Compatible with Alexa
  • Programmable “scenes” through the switchBot app
  • 70.5 x 25.5 x 23mm sensor, 35 x 12 x 12.5mm magnet
  • One-year warranty


The SwitchBot Contact Sensor comes packed in the brand specific white and red packaging. On the front we have a graphical representation of the contact sensor and on the bottom we have a list of compatible services, which includes pretty much all the big players in the market.

On the back, we have a small description of the sensor and also some examples of the automations you can create within the SwitchBot ecosystem, by combining the sensor with the SwitchBot Motion Sensor, the SwitchBot Hub Mini, the SwitchBot Bot or Switchbot Curtain.

Inside the box we find the two parts of the contact sensor, AAA batteries, and double-sided 3M tape for easy mounting and the installation manual.

Closer Look

The SwitchBot Contact Sensor is not the smallest door sensor you’ve seen. While the magnet is standard sized, the sensor itself is 70.5 by 25.5 by 23mm, which make it huge by current door sensor standards. The sensor itself is built from high quality plastic and the front has a rounded corners rectangle shaped button and a led light that indicates the status.

On the back we have the a back panel that easily opens to put in 2 x AAA batteries and it also holds the 3M double-sided tape.


To install the sensor you will need the Switchbot application, which is available on Android and IOS. If you don’t have an account you will need to create one. Once you have the application installed, you need to install the sensor where you want it to stay. The sensor is designed for 3 default installations: on the door, on the window or on furniture with doors (closets and such). We opted to install it on the house door and since the technical specs say it works within 30mm we opted for a normal frame install. First thing to do is install the batteries. The back panel has a cover which is easy to remove and you don’t need any tools to open and close it up.

In one minute or less you are ready to add the SwitchBot Contact Sensor to the application. From the application, hit the “+” button and you should have the Contact Sensor in the list at the very top of the screen. If you do not see it there, you can select it from the list. The application will guide you through the installation process. You have to long press the button on the top of the device until the led indicator starts flashing and click Next. You will be prompted to give the sensor a name and you are done. Everything takes 30 seconds, so basically you can have the sensor installed in 5 minutes or less from the moment you get it from the courier.

Once added, the app displays the current status of the sensors on the main page. If you have a SwitchBot Hub you can connect the sensor through it and enable it’s true capabilities. The app will ask you where you want to place the sensor and based on your choice it will give you instructions to install it in place. Here is where our problems started. Since we have a steel entry door, the frame is a bit thicker and there’s a bit of gap between the margin of the door and the left and right frame limits. This gap is actually exactly 30mm and the sensor had troubles sensing when the door was opened and closed. This being said I had to move the sensor to the top of the door, where the distance between the door itself and the frame is a lot smaller. With a little inconvenient I managed to get the sensor to work properly.

One thing to look for after you have added the Contact Sensor to the SwitchBot app is the firmware version update. If there is a new version available you should definitely download it as it will enhance the features.

Just like the Motion Sensor, the SwicthBot Contact Sensor actually has a lot of features such as luminosity sensor, which senses both bright and dim conditions. Moreover, if you press the button on the sensor after opening the door, it will act as a “Set Alarm” trigger, notifying the smart system that you are leaving the house. This action can trigger custom Scenes.

SwitchBot Hub + Contact Sensor = Scenes

Once you have selected the settings you need it is time to play with the Sensor. Paired up with a SwitchBot Hub, the  SwitchBot Contact Sensor can be integrated in the Scenes panel. Within the SwitchBot ecosystem, you can take advantage of the included sensors and you can create scenes based on them. You have 3 options, based on which, you can add triggers that can activate other devices from your SwitchBot Ecosystem: Contact, which itself has 5 options (exit home, enter home, opened, closed or left open), Motion detectio or no motion detected for a period of time and ambient brightness level. For example, if the sensor detects leaving home, the hub can command the camera to be turned on and enable notifications if movement is sensed or the door is opened. Also if the sensor detects motion if can command the lights to turn on or it can command your camera to record. Every scene is executed within seconds after triggering, which is very useful.

Smart Home Integration

To take things further, the SwitchBot Contact Sensor takes advantage of the more powerful third-party integrations. It works flawlessly with Amazon Alexa, Google Assistant and Samsung SmartThings. Within the Alexa app, you can use the sensor detection skills to trigger any other associated app or function.

Adding the sensor to our Google Assistant gives you the possibility to receive notifications on your Google devices, but nothing more, so not much is added to the table.

Everything changes when you add it to Samsung SmartThings, though. If you are like me and have a bunch of products from a bunch of smart providers, controlling them can be hard. I have Alexa’s in some rooms, Google in others and Samsung SmartThings to link what is left in-between. Within the Samsung Hub I set routines that will trigger when I leave home for example. The greatest feature was that I could control both SwitchBot products (light bulb), but also other products as well (smart wall plugs and smart wall switches) from other providers. Now, when I leave home, all my lights will turn off and my security devices will turn themselves on if they were not set to this stance previously.


The SwitchBot Contact Sensor is easy to use, install, packs a lot of features, is battery operated, works lightning fast, is very reliable and packs a lot of features in a small device which is also very affordable. Only issue I had with it was the magnetic contact distance which seems to be smaller than actually advertised. The sensor integrates in any smart setup you might have at home and fills a needed hole in any automation system, making it very versatile. Combined with the SwitchBot Hub, it works flawlessly.


Build Quality
Smart Home Integration

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