user27726: I want to know if it is possible to put a boundary or limit to the volume that passes through a water flow sensor, and close the pipe using a solenoid valve.
Example: I only want 400 ml of water to pass, so when the water flow sensor reads how much water has passed in the pipe, if 400 is reached, the solenoid will close the pipe.
Sorry for my bad English, it is not my first language. I'm hopping that someone can help me out.

user10394: Using a YF201 you cannot measure less than 1 litre / minute or more than 30 l/m.
(ref http://www.bc-robotics.com/tutorials/using-a-flow-sensor-with-arduino/)
The device sends a pulse for every 2.25ml that flows through it.  All you needs to do is take the amount you want to let through (400ml) and divide that by 2.25ml and you get 177.8 pulses.  So once your Arduino counts 178 pulses then you trigger the valve to close.
Its not going to be very accurate, because unless the valve closes instantly there will be a bit of an overshoot.  and you have to measure in units of 2.25ml.

user27957: hello @kaisar Great you have not mentioned which flow sensor are you using. I am assuming that you are using flow sensor YF-S201 or YF-S401(Hall Effect).You have to do Little calculation for measuring water flow.
In order to measure the quantity of water being passed in particular time through the water flow sensor it was first passed through the water flow sensor which was taken as input interface in the flow. Formulas are applied in order to measure the number of rotations/pulses in a minute of rotation.
Here I have determined flow rate by change in velocity of water. Velocity depends on the pressure that forces the through pipelines. As the pipe’s cross-sectional area is known and remains constant, the average velocity is an indication of the flow rate. The basis relationship for determining the liquid’s flow rate in such cases is
Q=VxA, where Q is flow rate/total flow of water through the pipe, V is average velocity of the flow and A is the cross-sectional area of the pipe
Calibration Factor = The hall-effect flow sensor outputs pulses per second per litre/minute of flow.(check your datasheet) here I have taken 4.5.
Flow Rate(litres/minute) = ((1000.0 / Total time) x Pulse Count) / calibration Factor
Flow Rate(MilliLitres/Second) = (Flow Rate / 60) x 1000
There you have to calculate the total water flow in a given time by adding flow rate for each second.
There after you have check your set point value(400ml)..if condition satisfied you you can turn off your Solenoid valve.
and the code is
int sensorInterrupt = 0;  // interrupt 0
int sensorPin       = 2; //Digital Pin 2
int solenoidValve = 5; // Digital pin 5
unsigned int SetPoint = 400; //400 milileter

/*The hall-effect flow sensor outputs pulses per second per litre/minute of flow.*/
float calibrationFactor = 4.5; //You can change according to your datasheet

volatile byte pulseCount =0;  

float flowRate = 0.0;
unsigned int flowMilliLitres =0;
unsigned long totalMilliLitres = 0;

unsigned long oldTime = 0;

void setup()
{
  
  // Initialize a serial connection for reporting values to the host
  Serial.begin(9600);
  pinMode(solenoidValve , OUTPUT);
  pinMode(sensorPin, INPUT);
  digitalWrite(sensorPin, HIGH);

  /*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); //you can use Rising or Falling
}

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(flowMilliLitres, DEC);  // Print the integer part of the variable
    Serial.print("mL/Second");
    Serial.print("\t");           

    // Print the cumulative total of litres flowed since starting
    Serial.print("Output Liquid Quantity: ");        
    Serial.print(totalMilliLitres,DEC);
    Serial.println("mL"); 
    Serial.print("\t");         
    If (totalMilliLitres =< 400)
    {
      SetSolinoidValveON();
    }
    else{ 
      SetSolinoidValveOFF();
        }


// 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++;
}

void SetSolinoidValveON()
{
  digitalWrite(solenoidValve, HIGH);
}
void SetSolinoidValveOFF()
{
  digitalWrite(solenoidValve, LOW);
}


27726: <p>I want to know if it is possible to put a boundary or limit to the volume that passes through a water flow sensor, and close the pipe using a solenoid valve.</p>

<p>Example: I only want 400 ml of water to pass, so when the water flow sensor reads how much water has passed in the pipe, if 400 is reached, the solenoid will close the pipe.</p>

<p>Sorry for my bad English, it is not my first language. I'm hopping that someone can help me out.</p>
 10394: <p>Using a YF201 you cannot measure less than 1 litre / minute or more than 30 l/m.
(ref <a href="http://www.bc-robotics.com/tutorials/using-a-flow-sensor-with-arduino/" rel="nofollow noreferrer">http://www.bc-robotics.com/tutorials/using-a-flow-sensor-with-arduino/</a>)</p>

<p>The device sends a pulse for every 2.25ml that flows through it.  All you needs to do is take the amount you want to let through (400ml) and divide that by 2.25ml and you get 177.8 pulses.  So once your Arduino counts 178 pulses then you trigger the valve to close.</p>

<p>Its not going to be very accurate, because unless the valve closes instantly there will be a bit of an overshoot.  and you have to measure in units of 2.25ml.</p>
 27957: <p>hello @kaisar Great you have not mentioned which flow sensor are you using. I am assuming that you are using flow sensor YF-S201 or YF-S401(Hall Effect).You have to do Little calculation for measuring water flow.
In order to measure the quantity of water being passed in particular time through the water flow sensor it was first passed through the water flow sensor which was taken as input interface in the flow. Formulas are applied in order to measure the number of rotations/pulses in a minute of rotation.</p>
<p>Here I have determined flow rate by change in velocity of water. Velocity depends on the pressure that forces the through pipelines. As the pipe’s cross-sectional area is known and remains constant, the average velocity is an indication of the flow rate. The basis relationship for determining the liquid’s flow rate in such cases is</p>
<p><strong>Q=VxA</strong>, where <strong>Q</strong> is flow rate/total flow of water through the pipe, <strong>V</strong> is average velocity of the flow and A is the cross-sectional area of the pipe</p>
<p><strong>Calibration Factor</strong> = <em>The hall-effect flow sensor outputs pulses per second per litre/minute of flow.(check your datasheet) here I have taken 4.5.</em></p>
<p><strong>Flow Rate(litres/minute)</strong> = <em>((1000.0 / Total time) x Pulse Count) / calibration Factor</em></p>
<p><strong>Flow Rate(MilliLitres/Second)</strong> = <em>(Flow Rate / 60) x 1000</em></p>
<p>There you have to calculate the total water flow in a given time by adding flow rate for each second.
There after you have check your set point value(400ml)..if condition satisfied you you can turn off your Solenoid valve.</p>
<p>and the code is</p>
<pre><code>int sensorInterrupt = 0;  // interrupt 0
int sensorPin       = 2; //Digital Pin 2
int solenoidValve = 5; // Digital pin 5
unsigned int SetPoint = 400; //400 milileter

/*The hall-effect flow sensor outputs pulses per second per litre/minute of flow.*/
float calibrationFactor = 4.5; //You can change according to your datasheet

volatile byte pulseCount =0;  

float flowRate = 0.0;
unsigned int flowMilliLitres =0;
unsigned long totalMilliLitres = 0;

unsigned long oldTime = 0;

void setup()
{
  
  // Initialize a serial connection for reporting values to the host
  Serial.begin(9600);
  pinMode(solenoidValve , OUTPUT);
  pinMode(sensorPin, INPUT);
  digitalWrite(sensorPin, HIGH);

  /*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); //you can use Rising or Falling
}

void loop()
{
   
   if((millis() - oldTime) &gt; 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(&quot;Flow rate: &quot;);
    Serial.print(flowMilliLitres, DEC);  // Print the integer part of the variable
    Serial.print(&quot;mL/Second&quot;);
    Serial.print(&quot;\t&quot;);           

    // Print the cumulative total of litres flowed since starting
    Serial.print(&quot;Output Liquid Quantity: &quot;);        
    Serial.print(totalMilliLitres,DEC);
    Serial.println(&quot;mL&quot;); 
    Serial.print(&quot;\t&quot;);         
    If (totalMilliLitres =&lt; 400)
    {
      SetSolinoidValveON();
    }
    else{ 
      SetSolinoidValveOFF();
        }


// 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++;
}

void SetSolinoidValveON()
{
  digitalWrite(solenoidValve, HIGH);
}
void SetSolinoidValveOFF()
{
  digitalWrite(solenoidValve, LOW);
}
</code></pre>
