Ive made the flow meter for a work project and I'm going to use the LCD to give me a read out of L/MIN.
Spent a few hours today getting a read out.
I have a read out from the flow meter using this code but this code doesn't have the LCD read out added
volatile int NbTopsFan; //measuring the rising edges of the signal
int Calc;
int hallsensor = 2; //The pin location of the sensor
void rpm () //This is the function that the interupt calls
{
NbTopsFan++; //This function measures the rising and falling edge of signal
} //The setup() method runs once, when the sketch starts
void setup()
{
pinMode(hallsensor, INPUT); //initializes digital pin 2 as an input
Serial.begin(9600); //This is the setup function where the serial port is initialised
attachInterrupt(0, rpm, RISING); //and the interrupt is attached
}
// the loop() method runs over and over again
// as long as the Arduino has power
void loop ()
{
NbTopsFan = 0; //Set NbTops to 0 ready for calculations
sei(); //Enables interrupts
delay (1000); //Wait 1 second
cli(); //Disable interrupts
Calc = (NbTopsFan * 60 / 7.5); //(Pulse frequency x 60) / 7.5Q = flow rate in L/hour
Serial.print (Calc, DEC); //Prints the number calculated above
Serial.print (" L/hour\r\n"); //Prints "L/hour" and returns a new line
}
I want to add some of this LCD read out to the code above
/*
This tutorial Demonstrates the use of Flow Sensor
Web: blog.circuits4you.com
The circuit:
Flow Sensor Connections
Yellow --- Pin 6
Red --- +5V
Black --- GND
LCD Connections
* LCD RS pin to digital pin 12
* LCD Enable pin to digital pin 11
* LCD D4 pin to digital pin 5
* LCD D5 pin to digital pin 4
* LCD D6 pin to digital pin 3
* LCD D7 pin to digital pin 2
* LCD R/W pin to ground
* 1K resistor:
* One end to ground
* Another end to LCD VO pin (pin 3)
This example code is in the public domain.
*/
// include the library code:
#include <LiquidCrystal.h>
// initialize the library with the numbers of the interface pins
LiquidCrystal lcd(12, 11, 5, 4, 3, 2);
volatile int FlowPulse; //measuring the rising edges of the signal
int Calc;
int flowsensor = 6; //The pin location of the sensor
void setup() {
pinMode(flowsensor, INPUT); //initializes digital pin 2 as an input
Serial.begin(9600); //This is the setup function where the serial port is initialised,
attachInterrupt(0, rpm, RISING); //and the interrupt is attached
// set up the LCD's number of columns and rows:
lcd.begin(16, 2);
// Print a message to the LCD.
lcd.setCursor(0, 1);
lcd.print("Flow Meter");
}
void loop() {
FlowPulse = 0; //Set NbTops to 0 ready for calculations
sei(); //Enables interrupts
delay (1000); //Wait 1 second
cli(); //Disable interrupts
Calc = (FlowPulse * 60 / 7.5); //(Pulse frequency x 60) / 7.5Q, = flow rate in L/hour
Serial.print (Calc, DEC); //Prints the number calculated above
Serial.print (" L/hour\r\n"); //Prints "L/hour" and returns a new line
// set the cursor to column 0, line 1
// (note: line 1 is the second row, since counting begins with 0):
lcd.setCursor(0, 2);
lcd.print(Calc,DEC); // print the Flow Rate
lcd.print(" L/hour");
}
void rpm () //This is the function that the interupt calls
{
FlowPulse++; //This function measures the rising and falling edge of the hall effect sensors signal
}
It says that the PIN read out is pin 6 but I cant a read out from pin 6 at all - I can only get a read out from pin 2.
The LCD also uses Pin 2 can I put two connections to pin 2 of the Arduino?
I can get a read out on the serial monitor of the flow rate but on the LCD it just gets stuck on "Flow Meter"
It should change to L/Hour
#include <LiquidCrystal.h>
// initialize the library with the numbers of the interface pins
LiquidCrystal lcd(12, 11, 5, 4, 3, 6);
volatile int FlowPulse; //measuring the rising edges of the signal
int Calc;
int flowsensor = 2; //The pin location of the sensor
void setup() {
pinMode(flowsensor, INPUT); //initializes digital pin 2 as an input
Serial.begin(9600); //This is the setup function where the serial port is initialised,
attachInterrupt(0, rpm, RISING); //and the interrupt is attached
// set up the LCD's number of columns and rows:
lcd.begin(16, 6);
// Print a message to the LCD.
lcd.setCursor(0, 1);
lcd.print("Flow Meter");
}
void loop() {
FlowPulse = 0; //Set NbTops to 0 ready for calculations
sei(); //Enables interrupts
delay (1000); //Wait 1 second
cli(); //Disable interrupts
Calc = (FlowPulse * 60 / 7.5); //(Pulse frequency x 60) / 7.5Q, = flow rate in L/hour
Serial.print (Calc, DEC); //Prints the number calculated above
Serial.print (" L/hour\r\n"); //Prints "L/hour" and returns a new line
// set the cursor to column 0, line 1
// (note: line 1 is the second row, since counting begins with 0):
lcd.setCursor(0, 2);
lcd.print(Calc,DEC); // print the Flow Rate
lcd.print(" L/hour");
}
void rpm () //This is the function that the interupt calls
{
FlowPulse++; //This function measures the rising and falling edge of the hall effect sensors signal
} ]
Just need to work out how to calculate the flow rate, I want a minimum of 4L per second
Working code
#include <LiquidCrystal.h>
// initialize the library with the numbers of the interface pins
LiquidCrystal lcd(12, 11, 5, 4, 3, 6);
volatile int FlowPulse; //measuring the rising edges of the signal
int Calc;
int flowsensor = 2; //The pin location of the sensor
void setup() {
pinMode(flowsensor, INPUT); //initializes digital pin 2 as an input
Serial.begin(9600); //This is the setup function where the serial port is initialised,
attachInterrupt(0, rpm, RISING); //and the interrupt is attached
// set up the LCD's number of columns and rows:
lcd.begin(16, 6);
// Print a message to the LCD.
lcd.setCursor(1,0);
lcd.print("Flow Rate Meter");
delay(1000);// wait 500ms // Delay to read text
lcd.clear(); // clear LCD display
}
void loop() {
FlowPulse = 0; //Set NbTops to 0 ready for calculations
sei(); //Enables interrupts
delay (1000); //Wait 1 second
cli(); //Disable interrupts
Calc = (FlowPulse * 6/ 7.5); //(Pulse frequency x 60) / 7.5Q, = flow rate in L/hour
Serial.print (Calc, DEC); //Prints the number calculated above
Serial.print (" L/Minn"); //Prints "L/hour" and returns a new line
// set the cursor to column 0, line 1
// (note: line 1 is the second row, since counting begins with 0):
lcd.begin(16,6);
lcd.setCursor(1, 0);
lcd.print(Calc, DEC); // print the Flow Rate
lcd.print(" L/Min");
}
void rpm () //This is the function that the interupt calls
{
FlowPulse++; //This function measures the rising and falling edge of the hall effect sensors signal
}
That is the crappiest way possible to read interrupts. If you are going to do nothing except wait for some other code to count state changes, you might as well forget interrupts and just use a while loop here watching for state changes.
cli(); //Disable interrupts
Calc = (FlowPulse * 6/ 7.5); //(Pulse frequency x 60) / 7.5Q, = flow rate in L/hour
Serial.print (Calc, DEC); //Prints the number calculated above
Serial.print (" L/Minn"); //Prints "L/hour" and returns a new line
There is a word that describes people that do Serial ouput with interrupts disabled. 6 letters, starts with s, rhymes with stupid.
Since the Arduino is doing nothing during the delay(), except dealing with interrupts, using interrupts is pointless. During that one second, using a while statement and millis() to loop for one second, read the pin over and over. Count the number of times the pin is HIGH when it was LOW last time. Look at the state change detection example.
Then get rid of all the crap dealing with interrupts.
Here is how to read and printout interrupt counts every second without delays. The reading of volatile variables from within an ISR is protected and the Serial printing does not occur when interrupts are disabled.
volatile unsigned long count = 0;
unsigned long copyCount = 0;
unsigned long lastRead = 0;
unsigned long interval = 1000;
void setup()
{
Serial.begin(115200);
Serial.println("start...");
attachInterrupt(0, isrCount, RISING); //interrupt signal to pin2
}
void loop()
{
if (millis() - lastRead >= interval) //read interrupt count every second
{
lastRead += interval;
noInterrupts(); //cli()
copyCount = count;
count = 0;
interrupts(); //sei()
Serial.println(copyCount);
}
}
void isrCount()
{
count++;
}
Strip out what you don't need, rather than re-invent the wheel. An hour is usually a long time, and you might want to re-think how you present the data.
If you want the rate, you need to (digitally) low-pass filter the number of counts per second (although
second may not be the best granularity depending on the pulse rates involved).
