Hi,
I’m working on interfacing the AS3935 Lightning Detection sensor with Particle’s Borons.
I’ve connected the 3.3V and GND pins to 3.3V and GND pins on Boron respectively. For the interrupt pin, I’ve connected it to D4 and I also connected the SPI pins in the following manner according to the datasheet:
CS → A4 (D14)
SCK → SCK (D13)
MISO → MISO (D12)
MOSI → MOSI (D11)
Using a multimeter, I’ve discovered that the IRQ pin is always high. Reading the datasheet, that is not the intended behavior (it should go up only after it detects an event); any ideas what could be causing this?
I’m using the SparkFun basic example adjusted to the Particle platform (change the pins to Dx).
Thank you so much in advance!
It can be high through register settings. We use it as active low, as indicated on our schematic, so it should be high during normal operation.
No, I’ve never seen a register setting to invert the IRQ signal. From the Sparkfun connection page:
“Heads up! There is a minor silkscreen error on the PCB for the interrupt pin. The interrupt pin is an active high as opposed to an active low as indicated image. The silkscreen has been updated.”
“The interrupt pin goes HIGH when the lightning detector has sensed an event, whether it’s lightning, a disturber, or noise. Make sure to connect to this pin to check if there is an event detected.”
OP, ignore the interrupt until you setup the Noise Floor, Antenna Tuning, gain etc.
IRQ goes high when asserted and stays high until you read the interrupt register. Lightning or noise can trigger the IRQ. If your power is noisy or an SMPS inductor is nearby that can also cause noise problems.
I did not have success with the AS3935 because the loop antenna LC tank is tuned to around 500kHz and AM radio stations even 580kHz still get picked up, causing false triggers depending on the song/announcer’s audio.