Here is the code:
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#include <LiquidCrystal.h>
LiquidCrystal lcd(7, 8, 9, 10, 11, 12);
const int vacPin = 0; // input pin for vacuum sensor
void setup() {
lcd.begin(20, 4);
}
void loop(){
float vac; // sensor value
float percent; // the mapped value
float vacBASE;
float mmHg;
vacBASE=37.00; // manually zero reading by inserting raw vacuum value to correct for offset voltage at zero vacuum
vac = (analogRead(vacPin) - vacBASE) * 1.06; // 1.06 to correct for sensor span of 4.7 V, not 5 V
percent = map(vac,0,1023,0,100);
lcd.setCursor(0, 0);
lcd.print("VACUUM: ");
mmHg=((percent*760)/100);
lcd.setCursor(0, 1);
lcd.print(mmHg,1);
lcd.print(" mm Hg ");
lcd.print(percent,1);
lcd.print("%");
delay(1000);
lcd.clear();
}