The choice of smart homes often starts with the purchase of basic sensors, and the first in line are usually motion sensors. However, once in the catalog, the user faces an incomprehensible confusion: seemingly identical white pucks can cost differently, have different designations and require completely different settings. The difference lies not only in the price, but also in the communication protocols, reaction speed and use scenarios that are available to the owner.
Understanding the technical nuances is critical, because buying the wrong model can give you a device that doesn’t work with the existing hub or will work unstable. In this article, we will detail the differences between the generations and versions of sensors from Xiaomi, Aqara and Mijia, so you can make an informed decision.
The main confusion arises from the fact that the Xiaomi brand uses sub-brands and ecosystems, which are often perceived as a single unit, although technically they may differ.We will look at Zigbee models, Bluetooth versions and hybrid solutions, explaining why some require a gateway and others work directly with the phone.
Evolution of protocols: Zigbee vs Bluetooth and Wi-Fi
The main watershed that distinguishes between sensors is the wireless protocol used. The older and most common models use Zigbee protocol. It's an energy-efficient standard that requires a dedicated gateway (hub) to connect to the Internet. These devices create a mesh network where each device can relay the signal, reinforcing the coverage throughout the house.
More modern versions often migrate to Bluetooth Mesh or direct Bluetooth LE. These sensors can connect directly to Bluetooth-enabled smartphones or smart speakers (such as Yandex Station or Xiaomi Smart Speaker) without requiring the purchase of a separate expensive gateway. However, their range without repeaters is limited, and they may be less responsive in complex automation scenarios.
There are also Wi-Fi models, but in Xiaomi’s lineup of compact motion sensors, they are less common because of high power consumption, usually specialized cameras or large sensors with their own power from the network. For stand-alone sensors, Wi-Fi is the way to quickly discharge the battery, so manufacturers are betting on energy-efficient protocols.
⚠️ Warning: When buying, be sure to check the logo on the package: "Works with Apple HomeKit" or "Requires Gateway" indicates a Zigbee protocol that won't work without a hub.
Generation comparison: from Aqara V1 to Motion Sensor 2
The first generation of sensors, known as the Aqara Human Body Sensor (the RTCGQ01LM model), has become an industry standard: a classic white cube with the Mijia or Aqara logo, which is compact but has a viewing angle of 170 degrees and a range of up to 7 meters, and their main advantage is their time-tested reliability and low price, but they do not have protection from moisture and require a flat surface to install.
The second generation, the Aqara Motion Sensor P1 (model RTCGQ13LM), has seen significant improvements, using millimeter wave detection technology that allows the sensor to respond even to micro-movements, such as breathing in a sleeping person or wiggling your fingers lightly when you type, which solves the perennial problem of "dorming" light when you sit still.
The third iteration, Motion Sensor 2 (model RTCGQ02LM), is a hybrid. This device supports two protocols at once: Zigbee 3.0 and Bluetooth 5.0. This duality makes it a versatile soldier: it can work in the Apple HomeKit ecosystem through Aqara hubs, connect to the Xiaomi Mi Home ecosystem or work with devices that support Bluetooth Mesh. In addition, it has increased protection from IP65 water, which allows you to install it even in the bathroom.
- 📡 RTCQ01LM: Classic Zigbee, requires hub, cheap, corner 170°.
- 🌊 RTCQ02LM: Zigbee + Bluetooth, waterproofing IP65, Support for HomeKit.
- 👁️ RTCQ13LM (P1): High accuracy, micro-movement detection, large radius.
The price difference between these models can be twofold, but it's justified by functionality. If you just need to turn on the lights in the hallway as you walk through, the first version will do. For complex scenarios where fixing a person in a static pose is important, you need to choose more advanced models with millimeter wave radars.
Visual differences and model marking
To avoid getting confused in a sea of Chinese letters and articles, it is important to be able to distinguish devices visually. The cases may be identical, but the color of the indicator or the logo on the front panel tells a lot. Mijia models often have a shield logo with the letter "Mi", whereas the Aqara sub-brand uses a stylized letter "A" or full name.
Note the back cover and the type of mount. Older models have a built-in stand leg that needs to be broken or rotated, which is not always convenient for re-installation. Newer versions, such as the Motion Sensor 2, often use magnetic mounting or more advanced sphere turning mechanisms to steer the sensor in the right direction without being dismantled from the wall.
Most sensors are powered by a standard CR2032 battery, but some specific or outdated models may require rare batteries or have a non-removable battery, which reduces the life of the device as a whole. Always check the specification on the box or on the product card before paying.
| Model | Protocol | Waterproofing | Viewing angle |
|---|---|---|---|
| Aqara V1 (ZNCMS01LM) | Zigbee | No. | 170° |
| Motion Sensor 2 | Zigbee + BT | IP65 | 170° |
| Motion Sensor P1 | Zigbee | No. | 170° |
| Philips Hue (for comparison) | Zigbee | No. | 130° |
Use cases and automation
The difference between sensors is not only in hardware, but also in the scenarios they allow to be implemented. Simple Zigbee sensors do a great job of getting in and turning on the lights. However, they often have a delay of 1-2 seconds before activation and can "lose" a person if they freeze. For a corridor or toilet, this is acceptable, but for a living room or office, it is no longer.
Smarter models with light detection (luxmeter) allow you to create complex circuits. For example, the sensor can not turn on light during the day, even if it detects movement, saving energy. In the Mi Home or Aqara Home application, you can adjust the light threshold below which the sensor begins to respond to movement.
Security scenarios are another area of application: motion sensors can send a push notification to a phone if you're driving at night or when no one's home. This is important for signal speed. Zigbee devices here are better off than Bluetooth because they're in the background and don't depend on the phone being in range.
☑️ Checking before purchasing a sensor
Compatibility issues and gateway choice
The most common mistake of beginners is to buy a sensor without knowing what it will connect to. If you chose a Zigbee model, you definitely need a gateway. Without it, the sensor will be just a useless piece of plastic. Gateways come in all sorts of ways: built into sockets, individual hubs from Aqara, built into lamps or even some models of Xiaomi air conditioners.
It’s important to consider the ecosystem. Aqara sensors work best with the Aqara Home app, giving you access to more subtle settings and scenarios than the standard Mi Home. However, if you’re using Home Assistant or other third-party platforms, you may need a specific type of Zigbee coordinator (like ConBee II or Sonoff Zigbee), as native Xiaomi hubs are often closed to local management without “crutches.”
When choosing a gateway, look for support for Zigbee 3.0. Older hubs may not see new sensors or work with them unstablely, and some gateways require an Internet connection to run local scenarios, which is a disadvantage for those who value the privacy and autonomy of the system.
⚠️ Warning: Don't try to connect Zigbee directly to the router. Routers distribute Wi-Fi, and sensors speak Zigbee. These are different worlds, and you need a gateway translator to translate.
Energy efficiency and service life
The issue of autonomy is acute, because changing the battery in a sensor glued high on a wall or in a hard-to-reach place is not often desirable. The Zigbee protocol here is great: one element of CR2032 is enough for 1.5-2 years of active operation, this is achieved by the fact that the sensor most of the time “sleeps” and wakes up only for milliseconds to transmit the signal.
Bluetooth models can consume more power, especially if they are often interviewed by a phone or speaker. The frequency of "pings" affects the life of the battery. If you notice that the sensor discharges in a couple of months, check the settings in the application - perhaps there is too aggressive status check mode or high frequency of reports.
Temperature also affects the chemistry inside the battery, and if you plan to put the sensor in an unheated garage or outdoors (even with IP65 protection), in winter, battery capacity can drop by 30-40%, and in such conditions, it is better to use lithium batteries, which are better able to tolerate low temperatures than standard alkaline batteries.