This reminds me:
I have been thinking of building a microcontroller-based electronic
ignition that would have a reasonably sophisticated table-based
algorithm for controlling spark advance based on RPM and manifold
vacuum. It would also have a control input that would let me
adjust the advance while driving, for optimizing the curves.
This would take maybe $25 in parts, and would do most of what
those fancy $300 aftermarket electronic ignition systems do.
There are a couple of open issues I need to figure out:
1: What is a good circuit for actually driving a coil?
Can I simply have the microcontroller drive a high-current,
high-voltage power transistor? Do I need some equivalent
of the condenser? Has anyone ever seen a schematic diagram
for a Crane or similar aftermarket electronic ignition?
2: Where can I find a manifold vacuum sensor that would interface
to the analog-digital convertor on the microcontroller? I'm
sure that any parts store would have something suitable on the shelf,
but where would I find the electrical specs?
If anyone has any links, references, or even answers, I'd love
to see them.
Doug Braun
'72 Spit
At 11:55 AM 2/26/01 , Ptegler wrote:
>It turned out to be a combination of which vac. advance curve,
>(where it starts, ends, and total advance supplied) which
>source of vac is being used, (ported or manifold)
>and the mechanical advance curves and engine/dist
>mech. timing.
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