Qwiic AS3935 Lightning Detector

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The AS3935 Franklin Lightning Detector gives you lightning detection for your next weather project. This sensor is capable of detecting lightning up to 40 km away with an accuracy of 1km to the storm front! On the product is a sensitive antenna tuned to pick up lightning events in the 500kHz band. When sensing an event the AS3935 utilizes an interrupt to the interrupt pin, distinguishes between false and real lightning events, and has a number of features to help calibrate lightning detection. For example, there are settings for detecting from indoors or detecting from outdoors, settings to change the threshold for false events, and settings to be alerted only after a certain number of lightning strikes to name a few. We've also written an Arduino Library to get you prepared for that upcoming storm! Check under the documents tab under Library and Example Sketches.

The product is capable of communicating over SPI or I2C and sports a Qwiic connector for fast implementation without the need for soldering.

Experimental Product: SparkX products are rapidly produced to bring you the most cutting edge technology as it becomes available. These products are tested but come with no guarantees. Live technical support is not available for SparkX products. Head on over to our forum for support or to ask a question.
  • Lightning Sensing
    • 40 km Range with accuracy of 1km in 14 steps
  • Features
    • Programmable Detection Levels
    • Distance to storm estimation
    • "Disturber" (false event) rejection algorithm
    • Indoor and Outdoor Settings
    • SPI and I2C Interfaces
    • Qwiic Enabled
  • Operating Range
    • Supply Voltage: 2.4V - 5.5V

Customer Comments

Customer Reviews

4.5 out of 5

Based on 2 ratings:

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2 of 2 found this helpful:

It's really Qwiic + 1 for the Interrupt line, but it runs great

tl;dr This board has a couple of small quirks, but works very well. Don't change the default i2C address, and plan on heating up your soldering iron.

There are two small issues with the breakout board to note.

1) It requires an interrupt line to be used along with the Qwiic connector, so it's not pure Qwiic. (You probably will need to solder a pin for the interrupt line, just plugging in a qwiic cable is not sufficient to run this breakout board.)

2) The I2C address is in the reserved range (below 0x07). The default address 0x03 is probably fine, since 0x03 and 0x02 addresses are reserved for CBUS which is now obsolete and no longer in use. Address options 0x00 and 0x01 could cause problems.

The address 0x00 is reserved for general call, and used to send a command to all i2c devices, so that would be a bad choice. The byte 0x01 is also reserved as a start byte for manual i2c transmission and would probably be a bad choice.


I read the spec sheet for the chip and these issues actually spring from the architecture of the chip itself, not from Sparkfun's design of the breakout board.

Those two quibbles aside, this detector works fine and is a good package.

AS3935 breakout boards are notoriously finicky and I've run across some painful design issues with AS3935 breakout boards from other vendors. (AS3935's can ring like the buzzer on a discount cat house, if the antenna design isn't done right.)

This design is stable. Mine doesn't drift into noise oscillations, after a long period of use. That alone is worth 5 stars.

Unique sensor

Great fun little sensor. I set mine up to ring a bell when lightning is near

That's a great project idea! Thank you for your review. :-)