filtering gating a single '0' ?

hello :) hope all is fine.

I have a signal that every once in a while fires out lots of

'0'000000000000000000000000000000000's

I really only need the first '0' ( for its timing) as I would like to trigger a metronome from this first 0 in the stream. ( all the other 0's that follow it are retriggering the metronome , making it go crazy fast)

is there an object that selects the first command it is given and nothing more. (until it is reset by a button perhaps?)

i thought a gate could let the first 0 through and then close before the others 0's went through?

thanks for any help.
:)