Introduction

A CircuitPython driver library for the Franklin AS3935 lightning detector. The driver supports connections via SPI and I2C.

Note

Sparkfun found I2C connections unreliable and chose not to support it in their product.

See the AS3935 datasheet for more details of chip operation.

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 or individual libraries can be installed using circup.

Installing from PyPI

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-as3935

To install system-wide (this may be required in some cases):

sudo pip3 install adafruit-circuitpython-as3935

To install in a virtual environment in your current project:

mkdir project-name && cd project-name
python3 -m venv .env
source .env/bin/activate
pip3 install adafruit-circuitpython-as3935

Running The Unittests

To run the unittests on you will need to install Pytest and Pytest Mock.

pip3 install pytest pytest-mock

To install system-wide (this may be required in some cases):

sudo pip3 install pytest pytest-mock

Usage Example

For a SPI connection:

"""Loop and wait for an event.

Note that the sensor only responds to lightning and certain kinds of noise,
so unless it is stormy, there's not much to see here.
"""
import time
import board
import biffobear_as3935

# Edit the chip select and interrupt pins to match the connections to your board

interrupt_pin = board.D7  # Connected to the sensor interrupt pin

# For a SPI connection (recommended)
spi = board.SPI()  # Works for most Adafruit and Blinka boards
cs_pin = board.D5  # Connect to the sensor chip select pin
sensor = biffobear_as3935.AS3935(spi, cs_pin, interrupt_pin=interrupt_pin)

# For an I2C connection
# i2c = board.I2C()  # Works for most Adafruit and Blinka boards
# sensor = biffobear_as3935.AS3935_I2C(i2c, interrupt_pin=interrupt_pin)

while True:
    if sensor.interrupt_set:  # An event has occurred
        # The interrupt_status is cleared after a read, so assign it
        # to a variable in case you need the value later.
        event_type = sensor.interrupt_status
        if event_type == sensor.LIGHTNING:  # It's a lightning event
            print(f"Strike Energy = {sensor.energy}")
            print(f"Distance to storm front = {sensor.distance} km")
        elif event_type == sensor.DISTURBER:
            print("False alarm")
    else:
        print("No event detected")
    # Minimum time between strike events is 1 second so poll frequently!
    time.sleep(0.5)

Contributing

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

Documentation

For information on building library documentation, please check out this guide.