Did any idea how to make ignition coil pulse detection with next :
1. Input via CD 40106 like filter
2. Output with LM 324.
3. All to work at 12V.

Function:

When pulse come to input of CD 40106 in output of LM 324 to we have +12V.
If pulse stop output must drop to 0V

I was look some similar from China but it was hard to make schematic becouse
PCB is to small and two layer SMD.
It is basic for automatic switch from gasoline to LPG in car....
Final end output is relay 12V 10A DC.

I do not want full project from someone but only idea....

Regards.