AMS AS3935 Franklin Lightning Sensor

The AS3935 sensor platform allows you to use your AS3935 sensor (AliExpress, AMS_AS3935) in order to get notified when a thunderstorm is getting close.

The AS3935 can detect the presence of lightning activity and provide an estimation on the distance to the head of the storm. The chip issues a notification through an interrupt pin.

Component/Hub

The AS3935 can be configured to use either the SPI or I²C protocol for data communication. First choose which communication method you want to use for the sensor, set the SI pin for the appropriate level and set up the ESPHome integration for the chosen communication method.

Module Pins

Module Pin

Description

VCC/VDD

Positive supply voltage

GND

Ground

SCL

I²C clock bus or SPI clock bus (according to SI setting)

MOSI

I²C data bus or SPI data input bus (according to SI setting)

MISO

SPI data output bus

CS

Chip Select (active low)

SI

Select Interface (GND → SPI or VDD → I²C)

IRQ

Interrupt (out)

EN_V

Voltage Regulator Enable

A0

I²C address selection LSB

A1

I²C address selection MSB
../../_images/as3935.jpg

AS3935 Lightning Sensor.

Over SPI

The as3935_spi sensor platform allows you to use your AS3935 sensor (AliExpress, AMS_AS3935) in order to get notified when a thunderstorm is getting close.

# Example configuration for SPI (decide for one!)
as3935_spi:
  cs_pin: GPIO12
  irq_pin: GPIO13
# Example lightning and energy sensor
sensor:
  - platform: as3935
    lightning_energy:
      name: "Lightning Energy"
    distance:
      name: "Distance Storm"
binary_sensor:
  - platform: as3935
    name: "Storm Alert"

Configuration variables:

  • cs_pin (Required, Pin Schema): The chip select pin.

  • irq_pin (Required, Pin): The IRQ pin, which indicates if a lightning strike has been detected.

  • indoor (Optional, boolean): Indicates if the sensor is used indoor. Defaults to true.

  • noise_level (Optional, int): Noise floor level is compared to known reference voltage. If this level is exceeded the chip will issue an interrupt to the IRQ pin, broadcasting that it can not operate properly due to noise (INT_NH). Defaults to 2.

  • spike_rejection (Optional, int): Helps to differentiate between false events and actual lightning. Increasing this value increases robustness at the cost of sensitivity to distant events. Defaults to 2.

  • lightning_threshold (Optional, int): The number of lightnings that must appear in a 15-minute time window before a lightning storm is detected. 15 minutes is the window of time before the number of detected lightning events is reset. The number of lightning strikes can be set to 1,5,9, or 16. Defaults to 1.

  • mask_disturber (Optional, boolean): This setting will return whether or not disturbers trigger the IRQ Pin. Defaults to false.

  • div_ratio (Optional, int): The antenna is designed to resonate at 500kHz and so can be tuned with the following setting. The accuracy of the antenna must be within 3.5 percent of that value for proper signal validation and distance estimation. Defaults to 0.

  • capacitance (Optional, int): This setting will add capacitance to the series RLC antenna on the product to help tune its resonance. The datasheet specifies being within 3.5 percent of 500kHz to get optimal lightning detection and distance sensing. It’s possible to add up to 120pF in steps of 8pF to the antenna. Defaults to 0.

  • watchdog_threshold (Optional, int): Determines the threshold for events that trigger the IRQ pin. Defaults to 2.

  • tune_antenna (Optional, boolean): Start sensor in antenna tuning mode. It will emit oscillator frequency to be read on the INT pin. Please follow AS3935 documentation. Note that while this mode is enabled, lightings will not be detected. It should be used for initial calibration only, in order to determine correct value of capacitance and/or div_ratio parameters. Defaults to False.

  • calibration (Optional, boolean): Enable/disable oscillator calibration on startup. It is recommended to perform antenna tuning procedure first and adjust parameters, so that RLC antenna resonance is tuned within optimal range. Defaults to True.

Over I²C

The as3935_i2c sensor platform allows you to use your AS3935 sensor (AliExpress, AMS_AS3935) in order to get notified when a thunderstorm is getting close.

# Example configuration for I²C (decide for one!)
as3935_i2c:
  irq_pin: GPIO12
# Example shared configuration
sensor:
  - platform: as3935
    lightning_energy:
      name: "Lightning Energy"
    distance:
      name: "Distance Storm"
binary_sensor:
  - platform: as3935
    name: "Storm Alert"

Configuration variables:

  • address (Optional, int): Manually specify the I²C address of the sensor. Defaults to 0x03 (A0 and A1 pins pulled high). The address is made up using the state of A0 as bit 1 and the state of A1 as bit 2, so a total of four addresses is possible.

  • irq_pin (Required, Pin): The IRQ pin, which indicates if a lightning strike has been detected.

  • indoor (Optional, boolean): Indicates if the sensor is used indoor. Defaults to true.

  • noise_level (Optional, int): Noise floor level is compared to known reference voltage. If this level is exceeded the chip will issue an interrupt to the IRQ pin, broadcasting that it can not operate properly due to noise (INT_NH). Defaults to 2.

  • spike_rejection (Optional, int): Helps to differentiate between false events and actual lightning. Increasing this value increases robustness at the cost of sensitivity to distant events. Defaults to 2.

  • lightning_threshold (Optional, int): The number of lightnings that must appear in a 15-minute time window before a lightning storm is detected. 15 minutes is the window of time before the number of detected lightning events is reset. The number of lightning strikes can be set to 1,5,9, or 16. Defaults to 1.

  • mask_disturber (Optional, boolean): This setting will return whether or not disturbers trigger the IRQ Pin. Defaults to false.

  • div_ratio (Optional, int): The antenna is designed to resonate at 500kHz and so can be tuned with the following setting. The accuracy of the antenna must be within 3.5 percent of that value for proper signal validation and distance estimation. Defaults to 0.

  • capacitance (Optional, int): This setting will add capacitance to the series RLC antenna on the product to help tune its resonance. The datasheet specifies being within 3.5 percent of 500kHz to get optimal lightning detection and distance sensing. It’s possible to add up to 120pF in steps of 8pF to the antenna. Defaults to 0.

  • watchdog_threshold (Optional, int): Determines the threshold for events that trigger the IRQ pin. Defaults to 2.

  • tune_antenna (Optional, boolean): Start sensor in antenna tuning mode. It will emit oscillator frequency to be read on the INT pin. Please follow AS3935 documentation. Note that while this mode is enabled, lightings will not be detected. It should be used for initial calibration only, in order to determine correct value of capacitance and/or div_ratio parameters. Defaults to False.

  • calibration (Optional, boolean): Enable/disable oscillator calibration on startup. It is recommended to perform antenna tuning procedure first and adjust parameters, so that RLC antenna resonance is tuned within optimal range. Defaults to True.

Sensor

A sensor platform to read lightning data

Configuration variables:

  • lightning_energy (Optional): Lightning energy value. According to the datasheet this is only a pure value that doesn’t have any physical meaning.

    • name (Required, string): The name for the lightning energy sensor.

    • id (Optional, ID): Set the ID of this sensor for use in lambdas.

    • All other options from Sensor.

  • distance (Optional): Distance in km to the front of the storm and not the distance to a lightning strike.

    • name (Required, string): The name for the distance sensor.

    • id (Optional, ID): Set the ID of this sensor for use in lambdas.

    • All other options from Sensor.

Binary Sensor

Binary sensor that indicates if a lightning strike was detected.

Configuration variables:

  • name (Required, string): The name of the binary sensor.

  • id (Optional, ID): Manually specify the ID used for code generation.

  • All other options from Binary Sensor.

See Also