İ need a cable lenght meter but i dont have any idea about how can i do it ?
it need to measure the length of the non-powered cable and display the coordinates and cable length online. ( it will worked by GSM)
it will be able to do the measurement at regular intervals or when I want.
i want to see online For example:
Cable Number :2 Lenght: 445,3m coordinate : 49.015577, 5.710104 Time : 03:22 PM
Cable length is tricky. As far as I know there is 2 methods that can be used:
Capacitance
Transmission delay
Capacitance will depend on the wire size and I think is better suited for small distance.
Transmission delay should be pretty accurate, but only for long distance. Maybe it would work on small distance but we are talking nanoseconds so I don't think an Arduino running at 16MHz would be able to do that.
Both would depend on the wire gauge and material. and Both would require a device to be plugged at the other end of the cable.
You would need a very specialized and sensitive circuit to perform this. An Arduino alone can not do that.