Arduino Vacuum Gauge

Initial build used a 10k pot in place of a vacuum gauge to make it simpler.

Arduino vacuum gauge.

Those sensors are ratiometric. The oled screen simply plugs in over the arduino which made for a nice compact board. 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. 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. 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. Pressure measurement methods air pressure measurement using mpx5010dp. Power them with the arduino 5v and use the arduino 5v as analog reference that is the arduino default setting.

Arduino code for air pressure measurement.