Rain Bucket debounce Interrupt and a 555 timer

My subject sounds like a title of a book,

Here's what I'd like to do, 
I want to build a circuit using a 555 timer in monostable vibrate mode, i want to connect the interrupt of the weather board to the trigger of the 555 timer, then using a cap and resistor define a specific output pulse which then is connected to the raspberry PI interrupt for the rain bucket.

I have built the 555 timer in mono stable mode and works with a manual input switch which pulls the voltage to ground and triggers the timer.

My question is thus simple, on the weather board is the rainbucket IRQ held high and on trigger goes low, or is it held low and on a trigger goes high? ( I dont have a scope and Im a newbie if i had one i would not know how to use it..) Im sure my answer is somewhere..

thanks in advance
Riccardo