so installed the rpm meter last night in the car tested it and it working alhamdulillah, made a video in the morning, one strange behavior, when the car starts the rpm rises to 2k rpm for a brief second like some one presses the throttle to start the car, is this normal, than the rpm stays at 1300 and gradually comes down to 800 when the engine reaches operating temperature.
//youtu.be/http://www.youtube.com/watch?v=1uHQXk7CyUU
here is the interface circuit that i made to get the rpm working, apart from this modified the tachometer from inside too, this is small enough to fit inside the housing hence more managed.
