////////////////////////////////////////////////////////////////////////////////
// Name:       waterflow-03 Florigs waterverbuik sensor                       //
//             01-Just trying to read and consquently set LEB_builtin         //
//             02-Create an interrupt to toggle LED_builtin                   // 
//             03-Software by instructables                                   // 
// http://robots/includes/parts.php?idpart=331                                //
// Created by: HARB rboek2@gmail.com may 2020 GPL copyrights                  //
// Platform:   Arduino Mega 2560                                              //
//             This program tests the interrupts on a MEGA 2560, but it       //
//             should run on any microcontroller that has at least 1 pin      //
//             available for user interrupts.                                 //
//                                                                            //
// As outputs the following modules are mounted:                              //
// - Standard Arduino Onboard LED (PWM)                                       //
//           http://robotigs.nl/robotigs/includes/parts_header.php?idpart=185 //
// - 3 color LED (PWM)                                                        //
//           http://robotigs.nl/robotigs/includes/parts_header.php?idpart=293 //
// - Activ loudspeaker / buzzer                                               //
//           http://robotigs.nl/robotigs/includes/parts_header.php?idpart=240 //
//                                                                            //
// As inputs the following modules are mounted:                               //
// - LDR                                                                      //
//           http://robotigs.nl/robotigs/includes/parts_header.php?idpart=46  //
//                                                                            //
// For communications are mounted:                                            //
// - Standard Serial Monitor output                                           //
//            http://robotigs.nl/robotigs/includes/parts_header.php?idpart=43 //
////////////////////////////////////////////////////////////////////////////////

/*
Liquid flow rate sensor -DIYhacking.com Arvind Sanjeev

Measure the liquid/water flow rate using this code. 
Connect Vcc and Gnd of sensor to arduino, and the 
signal line to arduino digital pin 2.
 
 */

byte statusLed    = 13;

byte sensorInterrupt = 0;  // 0 = digital pin 2
byte sensorPin       = 2;

// The hall-effect flow sensor outputs approximately 4.5 pulses per second per
// litre/minute of flow.
float calibrationFactor = 4.5;

volatile byte pulseCount;  

float flowRate;
unsigned int flowMilliLitres;
unsigned long totalMilliLitres;

unsigned long oldTime;

void setup()
{
  
  // Initialize a serial connection for reporting values to the host
  Serial.begin(57600);
   
  // Set up the status LED line as an output
  pinMode(statusLed, OUTPUT);
  digitalWrite(statusLed, HIGH);  // We have an active-low LED attached
  
  pinMode(sensorPin, INPUT);
  digitalWrite(sensorPin, HIGH);

  pulseCount        = 0;
  flowRate          = 0.0;
  flowMilliLitres   = 0;
  totalMilliLitres  = 0;
  oldTime           = 0;

  // The Hall-effect sensor is connected to pin 2 which uses interrupt 0.
  // Configured to trigger on a FALLING state change (transition from HIGH
  // state to LOW state)
  attachInterrupt(sensorInterrupt, pulseCounter, FALLING);
}

/**
 * Main program loop
 */
void loop()
{
   
   if((millis() - oldTime) > 1000)    // Only process counters once per second
  { 
    // Disable the interrupt while calculating flow rate and sending the value to
    // the host
    detachInterrupt(sensorInterrupt);
        
    // Because this loop may not complete in exactly 1 second intervals we calculate
    // the number of milliseconds that have passed since the last execution and use
    // that to scale the output. We also apply the calibrationFactor to scale the output
    // based on the number of pulses per second per units of measure (litres/minute in
    // this case) coming from the sensor.
    flowRate = ((1000.0 / (millis() - oldTime)) * pulseCount) / calibrationFactor;
    
    // Note the time this processing pass was executed. Note that because we've
    // disabled interrupts the millis() function won't actually be incrementing right
    // at this point, but it will still return the value it was set to just before
    // interrupts went away.
    oldTime = millis();
    
    // Divide the flow rate in litres/minute by 60 to determine how many litres have
    // passed through the sensor in this 1 second interval, then multiply by 1000 to
    // convert to millilitres.
    flowMilliLitres = (flowRate / 60) * 1000;
    
    // Add the millilitres passed in this second to the cumulative total
    totalMilliLitres += flowMilliLitres;
      
    unsigned int frac;
    
    // Print the flow rate for this second in litres / minute
    Serial.print("Flow rate: ");
    Serial.print(int(flowRate));  // Print the integer part of the variable
    Serial.print("L/min");
    Serial.print("\t");       // Print tab space

    // Print the cumulative total of litres flowed since starting
    Serial.print("Output Liquid Quantity: ");        
    Serial.print(totalMilliLitres);
    Serial.println("mL"); 
    Serial.print("\t");       // Print tab space
  Serial.print(totalMilliLitres/1000);
  Serial.print("L");
    

    // Reset the pulse counter so we can start incrementing again
    pulseCount = 0;
    
    // Enable the interrupt again now that we've finished sending output
    attachInterrupt(sensorInterrupt, pulseCounter, FALLING);
  }
}

/*
Insterrupt Service Routine
 */
void pulseCounter()
{
  // Increment the pulse counter
  pulseCount++;
}