Woops, thats funny, LOL. Your right, I will try the capacitor from R1/R2 to ground, that should make it less sensitive to spikes, about a 1/4 second or so.

 

Here's how I'd go about the modification:

Note that D1 and C1 have been added. This is to help provide stability for the voltage detector IC's supply during cranking.

I suggest that you start with a value of 1uF for C2; that will give about 20mS lag. I suggest you don't go more than about 5uF. Use caps rated for 50v or higher, or your leakage rate may be excessive. Use high-temp caps.

 

Note that D1 and C1 have been added. This is to help provide stability for the voltage detector IC's supply during cranking.

I suggest that you start with a value of 1uF for C2; that will give about 20mS lag. I suggest you don't go more than about 5uF. Use caps rated for 50v or higher, or your leakage rate may be excessive. Use high-temp caps.

Thats a very elegant solution, Thank you very much, this is turning out better than I had dreamed.

I have a female here but I can't find a circuit I like, so I'm going to leave the hysteria out.

 

I have a female here but I can't find a circuit I like, so I'm going to leave the hysteria out.

Good plan.

If you feel like downloading Cadsoft Eagle v4.16r2, you can have a look at the schematic and board layout I threw together.

You can download the latest version of Cadsoft Eagle if you want, but if you make any changes to the board or schematic, I won't be able to help you if you run into trouble.

 

Excuse me!!! It's possible to make reset of the latch state on the BATTERY disconnection ? Why My circuit hold the latch state when I connect the battery again?