Pressure measurement methods air pressure measurement using mpx5010dp.
Arduino vacuum gauge.
The processor in the vacuum gauge reads the 4 vacuum ports simultaneously digital filtering is applied to smooth out the vacuum readings useful on idling engines to get a steady reading the filtered value is then converted to kpa psi inhg or mmhg the calibration data from the eeprom is added to each of the vacuum readings.
Arduino code for air pressure measurement.
The oled screen simply plugs in over the arduino which made for a nice compact board.
When the 5v changes the resulting measured pressure does not change and is still accurate.
The vacuum gauge outputs 0 10vdc.
Absolute pressure is referenced to the pressure in a vacuum whereas gauge and differential pressures are referenced to another pressure such as the ambient atmospheric pressure or pressure in an adjacent vessel.
This had to be changed to a 0 5vdc range using a potential divider so it was compatible with the arduino.
Luckely they have also a vacuum sensor with a large range for example the mpxv6115v.
Those sensors are ratiometric.