// This is for the DEFAULT 5V analog reference.
// v = the voltage at the pin in Volts.
// p = the pressure in bar.
// Note that 'bar' is the pressure relative to the
// normal atmospheric pressure at that moment.
float v = (float) analogRead(A0) / 1024.0 * 5.0;
float p = v / 5.0 * 100.0;"

RawVoltage = (float) analogRead(A0) - 1;
float v = RawVoltage / 1024.0 * 4.0;
float p = v / 5.0 * 100.0;"