RFM98 LoRa Radio Node v1.0 ATmega328P 868MHz

The board uses an ATmega328P pre-loaded with the Arduino Pro Mini 8MHz 3.3V bootloader. Connect an FTDI programmer to the serial header pins (RX, TX, VCC, GND), select 'Arduino Pro or Pro Mini' as the board in the Arduino IDE, choose 'ATmega328P (3.3V, 8MHz)' as the processor, and set the programmer to 'USBasp' or 'AVRISP mkII'. You can then upload sketches that utilize LoRa libraries like RadioHead or Sandeep Mistry's LoRa library.

Current consumption depends heavily on the LoRa transmission mode and MCU sleep state. The RFM95 module can draw ~120mA during transmission at +20 dBm but drops to microamps in deep sleep. The ATmega328P also supports sleep modes. Using aggressive sleep scheduling and transmitting small packets infrequently, a standard 14500 LiPo (e.g., 800mAh) can last for several months. Always measure your specific application's duty cycle to estimate precise battery life.

The hardware is configured for the 868MHz ISM band, as indicated by the included antenna. While the underlying RFM95/SX1278 chip supports multiple frequency bands, switching to 915MHz requires modifying the center frequency in your LoRa library initialization code and, critically, replacing the antenna with a 915MHz-tuned model for proper impedance matching and regulatory compliance. The board's RF matching network may also be optimized for 868MHz.

The broken-out I2C ports allow connection of a wide range of sensors (temperature, humidity, pressure, VOC). The analog inputs (A0, A1) are suitable for reading voltage outputs from sensors like soil moisture probes or light-dependent resistors. Digital pins D3 (PWM-capable) and D4 can control relays, read switches, or interface with digital sensors. Ensure any connected peripheral is 3.3V logic compatible, as the board's I/O is not 5V tolerant.