New Xiaomi window and door sensor lasts up to three years. It can also monitor drawers

Have you left for the weekend and spent the whole journey wondering if you closed the bathroom window? Exactly these worries are addressed by an inconspicuous window and door sensor that shows you the status on your phone. Xiaomi has now introduced its third generation, named Xiaomi Door and Window Sensor 3, and the main new feature is extended battery life: the sensor is expected to function for up to three years on a single battery.

The principle remains the same as before. You attach the main unit to the door or window frame, and a magnet to the sash, and as soon as they separate, the sensor knows it’s open. A similar sensor was part of Xiaomi’s smart home starter kit, which we once tested. However, the new product is also suitable for drawers, cabinets, or storage boxes.

What has changed inside the sensor?

The previous model detected opening using a Hall probe, a classic magnetic field sensor. The third generation replaces it with a tunnel magnetoresistive sensor, which, according to Xiaomi, reacts faster and consumes less energy.

The more energy-efficient sensor is precisely what contributes to the longer battery life. The sensor is still powered by a common CR2032 button battery, but according to the manufacturer, with typical use, it will last up to three years instead of one year for the Xiaomi Door and Window Sensor 2.

In addition to the current status, the sensor also stores history. In the app, you will see individual openings, how many times a day the door or drawer was opened, and how long it remained open or closed. Parents, for example, can find out how often the candy cabinet is opened during the afternoon.

However, the new product has lost something. The second generation had a built-in illumination sensor, which the third generation lacks. Anyone who had automations tied to whether it was dark in the room will have to get light data from another device.

What do you need to monitor doors remotely?

The sensor communicates via Bluetooth, so for remote monitoring outside the home, you need a gateway with Bluetooth Mesh support, which some smart speakers and other Xiaomi devices can provide. The Xiaomi Home app then shows the current status and event history and sends notifications when it detects an unusual state.

More interesting is the connection with other appliances via the Xiaomi HyperOS Connect platform. The manufacturer gives examples such as turning on the light when a door opens, turning off the air conditioning when a window is open, or a reminder to close windows when it starts to rain or humidity rises. However, you must set up automations manually and purchase connected devices separately.

The sensor body is compact and thin, so it fits even into a narrow gap by the door frame or into a cabinet. On the cover, you will find the marked installation direction, which makes it easy to align the main unit with the magnet. This reduces the risk of the sensor being triggered unnecessarily due to crooked installation.

Price and Availability

In China, the sensor will start selling via crowdfunding on October 12 for 44 yuan, which is approximately 140 CZK (converted). The regular price after the campaign is expected to be 49 yuan, which is about 155 CZK.

When and if the new product will arrive in the Czech Republic, the manufacturer has not yet said. However, the previous generation is sold here; you can buy it on Alza for about 300 CZK, so there’s a good chance that the third generation will also arrive here.

Do you monitor your windows and doors at home with smart sensors?

Sources: Ximitime, Xiaomi Miui Hellas