The SONOFF AirGuard TH Pressure (SNZB-02M) is a Zigbee 3.0 wireless temperature, humidity, and air pressure sensor.
The sensor measures ambient temperature, relative humidity, and air pressure. Based on the measured data, the system also calculates dew point and VPD values. VPD (Vapor Pressure Deficit) is calculated from air temperature and humidity and can be used to evaluate the transpiration environment of plants.
The device is battery-powered and does not have a display, so measurement values are available through the connected Zigbee gateway or smart home system. The manufacturer specifies an expected battery life of approximately two years, depending on measurement and reporting settings as well as environmental conditions.
The SNZB-02M can be mounted magnetically or using the included metal plate. It is designed for indoor use, with a recommended installation height of up to 2 metres.
About SONOFF
SONOFF manufactures smart home devices, Zigbee sensors, relays, switches, controllers, and gateways. Its product range includes Wi-Fi, Zigbee, Bluetooth, and, for selected models, Matter-compatible devices.
SONOFF's official platform is eWeLink. Zigbee devices can also be integrated into other systems, such as Home Assistant, Zigbee2MQTT, or ZHA, using an appropriate Zigbee coordinator or gateway.
Key Product Features
- 5-in-1 environmental monitoring: Measures temperature, relative humidity, and air pressure, and calculates dew point and VPD values.
- Zigbee 3.0 communication: Low-power wireless connection based on IEEE 802.15.4.
- Battery-powered operation: Uses one non-rechargeable CR2477 lithium coin cell battery.
- Long battery life: Approximately two years, depending on configuration and operating conditions.
- Display-free design: Measurement values are displayed through the connected gateway or smart home platform.
- Flexible mounting: Can be attached directly to a magnetic surface or installed using the metal plate with adhesive or screws.
- Flexible installation: Designed for indoor use, with a recommended installation height of up to 2 metres.
Measurement Functions
- Temperature: Ambient temperature measurement accuracy of up to ±0.2 °C.
- Relative humidity: Humidity measurement accuracy of up to ±2% RH.
- Air pressure: Air pressure measurement accuracy of up to ±0.1 hPa.
- Dew point: Calculated from temperature and humidity data and indicates the temperature at which the air becomes saturated and condensation may begin.
- VPD: Vapor Pressure Deficit calculated from air temperature and humidity. In plant cultivation, it can be used to evaluate the transpiration environment.
Smart Home Protocols and Platform Compatibility
- Primary communication: Zigbee 3.0 over a 2.4 GHz radio connection.
- Zigbee gateway: A Zigbee gateway or local Zigbee coordinator is required for operation.
- SONOFF eWeLink: Can be used in the eWeLink application through a SONOFF Zigbee gateway.
- Other Zigbee gateways: Can also be used with third-party Zigbee 3.0-compatible gateways; actual support depends on the specific gateway.
- Home Assistant: Can be used with a compatible Zigbee coordinator and supported integration.
- Zigbee2MQTT: Can be integrated depending on the supported device list and the current Zigbee2MQTT configuration.
- ZHA: Can be used with the Home Assistant ZHA integration; compatibility depends on the current device profile and support status.
- MQTT: Does not have native MQTT support. When used with Zigbee2MQTT, it can be integrated into MQTT-based automations.
- HTTP and REST API: The device does not have a native HTTP or REST API. Such access may be provided by the gateway or smart home platform being used.
- LAN and offline operation: Can operate without an internet connection when used with a local Zigbee coordinator; however, the device itself does not have a direct LAN connection or web interface.
Technical Specifications
- Manufacturer: SONOFF
- Model: SNZB-02M
- Product type: Zigbee temperature, humidity, and air pressure sensor
- Communication: Zigbee 3.0
- Radio standard: IEEE 802.15.4
- Frequency range: 2405–2480 MHz
- Radio output power: Up to 10 dBm
- Power supply: 1 × CR2477, 3 V nominal voltage
- Battery type: Non-rechargeable lithium coin cell
- Battery life: Up to 2 years, depending on use and settings
- Temperature measurement accuracy: Up to ±0.2 °C
- Humidity measurement accuracy: Up to ±2% RH
- Air pressure measurement accuracy: Up to ±0.1 hPa
- Display: None
- Mounting: Magnetic mounting or metal plate with adhesive or screws
- Use: Indoor
- Maximum installation height: 2 m
- Zigbee operating frequency: 2.4 GHz ISM band
