sin cos signal into digital using arduino

hi everyone,

im working on a project in which im trying to convert my car speedometer (REAL CAR) into digital, is that possible using Arduino and what are the things needed, also i have 2 option i want to share :

NO.1 : i take the signal coming directly from the speed sensor which is a VSS+ signal and use Arduino to convert it into digital.

NO.2 : i just remove the needle motor which takes a sin cos signal and use Arduino to convert this reading into digital.

i would prefer option no2 however i want to know how can i achieve this using Arduino.

thanks in advance

Why not No 1? Use an opto copler to interface to the 5 volt world asuming the signal is frequency.

This explains #2 link. It is using Excel, but the arduino could do the same.

thanks, that was helpful, however is it OK if i connect the signals directly to Arduino meaning that i don't need any converter

That depnds on what the voltage levels are for your signals. I have no idea what they are. If they are 0-5V then you can directly connect them but it still may be safer to use an optical isolator. If it is something like 12V, then you will need to use a level shifter or a voltage divider or similar.

the circuit that provides the signal has this IC in it (nd SE125), also i will try to connect everything in the car and measure the signal voltage to make sure what values it gives.

thanks again