adafruit-circuitpython-rfm9x 1.1.6

CircuitPython library for RFM95/6/7/8 LoRa 433/915mhz radio modules.

Introduction

CircuitPython module for the RFM95/6/7/8 LoRa 433/915mhz radio modules.

Dependencies

This driver depends on:

• Adafruit CircuitPython

• Bus Device

Please ensure all dependencies are available on the CircuitPython filesystem. This is easily achieved by downloading the Adafruit library and driver bundle.

Usage Example

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.

Contributing

Contributions are welcome! Please read our Code of Conduct before contributing to help this project stay welcoming.

Building locally

Zip release files

To build this library locally you’ll need to install the circuitpython-build-tools package.

python3 -m venv .env
source .env/bin/activate
pip install circuitpython-build-tools

Once installed, make sure you are in the virtual environment:

source .env/bin/activate

Then run the build:

circuitpython-build-bundles --filename_prefix adafruit-circuitpython-rfm9x --library_location .

Sphinx documentation

Sphinx is used to build the documentation based on rST files and comments in the code. First, install dependencies (feel free to reuse the virtual environment from above):

python3 -m venv .env
source .env/bin/activate
pip install Sphinx sphinx-rtd-theme

Now, once you have the virtual environment activated:

cd docs
sphinx-build -E -W -b html . _build/html

This will output the documentation to docs/_build/html. Open the index.html in your browser to view them. It will also (due to -W) error out on any warning like Travis will. This is a good way to locally verify it will pass.