I just purchased a ThunderBoard, but no lightning simulator, so am trying to test it with the spark from a piezo butane lighter (the recommended method for a more primitive lightning detector I once had).
At about one foot distance, I get instances of "Interrupt reason= 0". Another post says this means false detect (but it's not one of the listed interrupts in the Interrupt Management section of the AS3935 Data Sheet). It seems reasonable that the spark wouldn't look like lightning to the ThunderBoard.
But if I farther decrease the distance, Python function read_i2c_block_data generates IOError 121 and the Interrupt reason is not available. Sometimes the unit even seems to become nonresponsive.
Is this error likely to occur in normal operation? Is the spark actually disturbing the logic of this board (the irony!)?
I tried disconnecting the Int line at the ThunderBoard end and the spark still generates an interrupt. I'm now interpreting "Interrupt reason= 0" to mean the board itsef didn't generate the interrupt. I suspect the spark is interfering with the I2C signals too, hence the IOError.
So I'm going to quit worrying about this error, except to trap and log it to see if it happens normally.
Yes, bringing my cellphone within a couple of inches of the board does generate interrupts, so I think I'll use this to test my setup instead of the spark.
BTW my Raspberry Pi caused some interference too, which ceased when I lengthened the connections and separated it from the board by at least a foot.