The arduino uses a 10 bit adc and outputs integers from 0 to 1023. You would use map (x, 0, 1023, 1, 4). With the map function as it is currently the only time position 4 would be active is when the ...

As C1 and C2 are to be determined, Arduino has the map () function that calculates the two variables runtime from two given mapping points (I1, O1) and (I2, O2).