Home-brewing an ignition advance control

[Donovan_Dibble at ittauto.com]

Al,

I've been thinking of making a similar system.  I want (am) going to use a
PIC 1674 uP for the 'brains'.  This micro has built in A/D for MAP, TPS,
etc.
This will hopefully make the system more compact.  Although I haven't
worked
on it in a while, I planned on starting by collecting data from a 'regular'
HEI distributor with vacuum/mechanical advance and simply implementing that
strategy into the micro.  Later, the knock sensor input and associated
retard
logic would be added.  I think the easiest (or most straightforward) way of
detecting knock will be with external op-amp filters rather than
calculating
Fourier Transforms within the micro.  Any signal conditioning would also be
taken care of with the op-amps.  I got as far as getting the vacuum vs.
advance data for the HEI but haven't taken it any further.  If you or the
list
have any other ideas, I'd like to hear them.  Any motivational ideas would
be
welcomed too :)

Don


>I have been pouring over the HEI 4-pin and 7-pin diagrams and info on this
>page.  The amount of info that is to be found on this page is FANTASTIC!
I
>am trying to figure out how to make an ignition advance control for a GM
HEI.
>I know MSD sells one but I would like to make my own if possible.  It's a
lot
>more satisfying that way and I learn alot more.  Is this done with an
>adjustable timer IC or is it some other kind of signal conditioning.
>
>Any Ideas???
>
>Thanks for listening
>Al Ross