Hi Phil, Just a thought regarding pulse counting of the jack (Actuator arm). Feed DC to the reed switch and then detect it with an opto coupler with the appropriate series resistor. Then count the pulses from the output transistor of the opto-coupler. This will stop the false counts from noise etc. I would be very interested in your results with this project as pulse counting has lots of merit as an accurate position sensor.

Regards,

Steve. VK2XDE