Using two flow sensors connected to one Arduino.

Using Arduino Sensors
5

I think I am into something here:

#include <Wire.h>
#include <LiquidCrystal_I2C.h>
LiquidCrystal_I2C lcd(0x27,16,2);

byte sensorA = 0;
byte sensorB = 1;
byte sensorPinA = 2;
byte sensorPinB = 3;

float calibrationFactor = 50;

volatile byte pulseCount;

float flowRate;
unsigned int turFuel;
unsigned int returFuel;

unsigned long oldTime;

void setup()
{
lcd.begin(16, 2);
lcd.setCursor(0, 0);
lcd.print(" ");
lcd.setCursor(0, 1);
lcd.print(" ");

Serial.begin(38400);

pinMode(sensorA, INPUT);
pinMode(sensorB, INPUT);

pulseCount  = 0;
flowRate    = 0.0;
turFuel     = 0;
returFuel   = 0;
oldTime     = 0;

attachInterrupt(sensorA, pulseCounter, FALLING);
attachInterrupt(sensorB, pulseCounter, FALLING);
}

//hovedprogrammet i loop.

void loop()
{
if((millis() - oldTime > 1000))
{
detachInterrupt(sensorA);
detachInterrupt(sensorB);

flowRate = ((1000.0 / (millis() - oldTime)) * pulseCount) / calibrationFactor;

oldTime =millis();

flowRate = (sensorA - sensorB) / 8500;

unsigned int frac;

Serial.print(int(flowRate));
Serial.print(".");
frac = (flowRate - int(flowRate)) * 10;
Serial.print(frac, DEC) ;

Serial.print(" ");
Serial.print(flowRate);

lcd.setCursor(0, 0);
lcd.print(" ");
lcd.setCursor(0, 0);
lcd.print("Flow: ");
if(int(flowRate) < 10)
{
lcd.print(" ");
}
lcd.print((int)flowRate);
lcd.print('.');
lcd.print(frac, DEC) ;
lcd.print(" L");
lcd.print("/min");

pulseCount = 0;

attachInterrupt(sensorA, pulseCounter, FALLING);
attachInterrupt(sensorB, pulseCounter, FALLING);
}

void pulseCounter()
{
  pulseCount++;
}

Or what do you think? I get a problem in one of the last lines in this code. Can anyone help with that problem?

Regards, Fredrik.