i have a 12v linear actuator that is ip67 rated that will be used underwater. I want to keep track of it's position. problem is i can't compromise the unit at all. I contacted the supplier and they said they figure out the distance traveled based on the dc motor's pulses. I did some searching on the forums but got flooded with pwm posts so i'm looking for some advice from you guys. How would i count the pulses of a dc motor?