Making alloca more safe

[BCS]

Hello Walter,

> BCS wrote:
> 
>> Yes the ignition (as the the key) doesn't turn off but when the
>> engine quits running the ignition system (as in the magneto or that
>> block of epoxy and silicon under the hood) quits triggering the
>> spark. Tie into that.
>> 
> Trying to determine if the distributor is no longer turning is a
> non-trivial circuit. Best to stick with simple things when dealing
> with safety issues. The inertial switch is pretty darned simple, it's
> just a ball stuck on the end of a magnet. Knock it hard, it falls off
> the magnet, opening the circuit.
> 

If you can find the right spot to tie into all you need is an event failure 
alarm

http://www.elektropage.com/default.asp?page=sub&bid=1&sid=18

A voltage divider across the points for a magneto should work. A more modern 
system should be even easier as they probably have a low voltage wire somewhere 
that will work.

Of course all the motivations change if your driving in a race.