I want to power a Sonalert if the ignition is turned on and engine hasn't been started within ~30 sec. Standard GMC V-8 with points-ignition, and an 14V alternator. Have access to both sides of the ignition key switch and a wire from the distributor points (already feeds tach). I need to turn on the ignition switch on my boat to raise or lower the outdrive, and I have left the ignition switch on.

I'm thinking about a delay timer whose timing period is reset by the distributor signal (so that it never times out if the engine is running) or a voltage detector & timer (to detect 14V from the alternator if the engine is turning) .

Anybody come up with something simpler?

 

You could just move the line to the lift and lower system to a separate switch independent of the ignition or move it over to the ACC side. Just a thought.

A simple 555 timer with a few additional components could easily be set up as a time delay device too. Just use the power that come back from the ignition coil to the tach to trigger a transistor that keeps pulling the 555 reset down/or up when the engine is running.

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No accessory contact on the ignition key switch, just +12V, IGN and START (momentary). The lift has an indicator lamp which lights to tell you that the outdrive is not down and locked, so it it is wired through the ignition switch so that the lamp only comes on when engine is running, and doesn't stay on all night while beached.

The problem is that after putting the boat on the trailer, I sometimes have to turn on the ignition switch to raise the outdrive and that's when I have left the key on. Moving the power feed to its own circuit is problematic because if the engine is running, you want to know that the outdrive is not up before you go in gear, and if there was a separate switch it could be in the wrong position. Maybe some diodes to power the lift circuit either from its own switch OR from the IGN switch?