CircuitPython module for the RFM95/6/7/8 LoRa 433/915mhz radio modules.
This driver depends on:
Please ensure all dependencies are available on the CircuitPython filesystem. This is easily achieved by downloading the Adafruit library and driver bundle.
On supported GNU/Linux systems like the Raspberry Pi, you can install the driver locally from PyPI. To install for current user:
pip3 install adafruit-circuitpython-rfm9x
To install system-wide (this may be required in some cases):
sudo pip3 install adafruit-circuitpython-rfm9x
To install in a virtual environment in your current project:
mkdir project-name && cd project-name python3 -m venv .venv source .venv/bin/activate pip3 install adafruit-circuitpython-rfm9x
Initialization of the RFM radio requires specifying a frequency appropriate to your radio hardware (i.e. 868-915 or 433 MHz) and specifying the pins used in your wiring from the controller board to the radio module.
This example code matches the wiring used in the LoRa and LoRaWAN Radio for Raspberry Pi project:
import digitalio import board import busio import adafruit_rfm9x RADIO_FREQ_MHZ = 915.0 CS = digitalio.DigitalInOut(board.CE1) RESET = digitalio.DigitalInOut(board.D25) spi = busio.SPI(board.SCK, MOSI=board.MOSI, MISO=board.MISO) rfm9x = adafruit_rfm9x.RFM9x(spi, CS, RESET, RADIO_FREQ_MHZ)
Note: the default baudrate for the SPI is 50000000 (5MHz). The maximum setting is 10Mhz but transmission errors have been observed expecially when using breakout boards. For breakout boards or other configurations where the boards are separated, it may be necessary to reduce the baudrate for reliable data transmission. The baud rate may be specified as an keyword parameter when initializing the board. To set it to 1000000 use :
# Initialze RFM radio with a more conservative baudrate rfm9x = adafruit_rfm9x.RFM9x(spi, CS, RESET, RADIO_FREQ_MHZ, baudrate=1000000)
Optional controls exist to alter the signal bandwidth, coding rate, and spreading factor settings used by the radio to achieve better performance in different environments. By default, settings compatible with RadioHead Bw125Cr45Sf128 mode are used, which can be altered in the following manner (continued from the above example):
# Apply new modem config settings to the radio to improve its effective range rfm9x.signal_bandwidth = 62500 rfm9x.coding_rate = 6 rfm9x.spreading_factor = 8 rfm9x.enable_crc = True
See examples/rfm9x_simpletest.py for an expanded demo of the usage.
API documentation for this library can be found on Read the Docs.
For information on building library documentation, please check out this guide.
Contributions are welcome! Please read our Code of Conduct before contributing to help this project stay welcoming.