Could splice up a short length of wire with a male and female bullet connector at each end. Connect it inline on the orange or white points wire. Tap off it directly, or with an inductive coil if there is enough flux on the 12V line to sense, and feed that into the diode side of an optocoupler. Feed the other side into the microcontroller. When the points are closed it will conduct to ground and trigger the optocoupler. When the points open, current doesn't flow, and the optocoupler is not triggered.
Not sure whether it would interfere much with the function of the ignition coils. I want to say it wouldn't be an issue since the condenser already soaks up the charge from the flux that feeds back into the primary ignition coil. As long as the sensing circuit itself is protected against damage by the counter-emf everything should work all right.
Not sure whether it would interfere much with the function of the ignition coils. I want to say it wouldn't be an issue since the condenser already soaks up the charge from the flux that feeds back into the primary ignition coil. As long as the sensing circuit itself is protected against damage by the counter-emf everything should work all right.