The BME34K262A is a highly integrated soil monitoring module kit consisting of an adapter board and the BM25S2621-1 module based on capacitive sensing to monitor soil moisture and temperature changes in real-time. The module converts signals through the adapter board and supports UART communication, facilitating easy integration into various smart agricultural systems such as automatic irrigation control and greenhouse monitoring.
The humidity unit used by the module is RH (Relative Humidity), which indicates the degree of water vapor saturation in the current soil, expressed as a percentage. For example, 50%RH means the current water vapor content is 50% of the maximum capacity at that temperature. A higher RH indicates wetter soil.
Core Functions
- Real-time Monitoring: Built-in capacitive sensor for soil moisture detection and NTC resistor for soil temperature detection.
- Automatic Sleep Mode: Under 5V supply, the module automatically enters low-power standby mode if no command is received from the host within 5 seconds.
- On-board Jumper Adjustment: The jumper selects whether to connect the 120Ω terminal resistor. Disconnecting the jumper includes it in the circuit to prevent signal reflection.
- Multi-module Bus Connection: Supports multiple modules connected to the same RS485 bus to form a single-master multi-slave system.
Featuring a highly stable capacitive moisture sensor and a high-precision NTC temperature sensor combined with a waterproof and rustproof design, it guarantees stable operation even when buried in soil long-term.
Operating Steps
This product is ready for use after verifying the wiring connections.
1. Wiring Verification: Refer to the connection diagram to link the main control board to the BMCOM interface of the adapter board, ensuring correct pin alignment (VDD, GND, TX, RX, STA).
2. Module Initialization: Supply 3.3V ~ 5.5V power via VDD. The module starts automatically upon power-up and will enter sleep mode if no communication command is received within 5 seconds.
3. Sending Commands: The host sends UART commands to read the current moisture and temperature data.
4. Multi-module Management (Advanced): When connecting multiple modules on the RS485 bus, connect the VDD, GND, RS485-A, and RS485-B lines of all BM25S2621-1 modules together to the wiring terminals on the adapter board.
⬥ For detailed information, please refer to the "Communication Interface" and "Application Circuit" sections in the datasheet.
Recommended to Use With: BMduino UNO / Arduino UNO
This module natively provides a standard BMCOM interface, making it perfect for direct connection to the BMduino UNO development board. It is also compatible with the standard Arduino UNO platform by importing the officially provided Arduino Library, allowing you to quickly build automated irrigation and smart agricultural monitoring systems.
