Home-brewing an ignition advance control

[am018]

Sounds fairly sound --
My knock sensing idea revolves around using is to take the ouput from a
knock sensor
via a pre-amp to a filter then drive an  LM3915 or LM3916 LED driver via
either the peak detection or power averaging circuits shown in
datasheets for
theses ICs. For a knock  indicator it would stop there -- but the  the
LM3915/6
LED outputs could be used as comparator outputs and passed to a PIC
device.   A
selected high level indicating  knock.  The lowest level should be
continuously
"on" when the engine is running and could be used to indicate the knock
sensor
is healthy.
Am I going off the rails or will this work ?

Andy Mcf