I seen a lot of old post on this but nothing recent. I was thinking about using a Liquid Flow Meter from adafruit for my kegerator to measure how much beer is left in the keg. I would be using an LCD, breadboard and also a Arduino Uno R3 to put this together.
I will modify the Adafruit liquid flow meters sample code.
/**********************************************************
This is example code for using the Adafruit liquid flow meters.
Tested and works great with the Adafruit plastic and brass meters
------> http://www.adafruit.com/products/828
------> http://www.adafruit.com/products/833
Connect the red wire to +5V,
the black wire to common ground
and the yellow sensor wire to pin #2
Adafruit invests time and resources providing this open source code,
please support Adafruit and open-source hardware by purchasing
products from Adafruit!
Written by Limor Fried/Ladyada for Adafruit Industries.
BSD license, check license.txt for more information
All text above must be included in any redistribution
**********************************************************/
#include "LiquidCrystal.h"
LiquidCrystal lcd(7, 8, 9, 10, 11, 12);
// which pin to use for reading the sensor? can use any pin!
#define FLOWSENSORPIN 2
// count how many pulses!
volatile uint16_t pulses = 0;
// track the state of the pulse pin
volatile uint8_t lastflowpinstate;
// you can try to keep time of how long it is between pulses
volatile uint32_t lastflowratetimer = 0;
// and use that to calculate a flow rate
volatile float flowrate;
// Interrupt is called once a millisecond, looks for any pulses from the sensor!
SIGNAL(TIMER0_COMPA_vect) {
uint8_t x = digitalRead(FLOWSENSORPIN);
if (x == lastflowpinstate) {
lastflowratetimer++;
return; // nothing changed!
}
if (x == HIGH) {
//low to high transition!
pulses++;
}
lastflowpinstate = x;
flowrate = 1000.0;
flowrate /= lastflowratetimer; // in hertz
lastflowratetimer = 0;
}
void useInterrupt(boolean v) {
if (v) {
// Timer0 is already used for millis() - we'll just interrupt somewhere
// in the middle and call the "Compare A" function above
OCR0A = 0xAF;
TIMSK0 |= _BV(OCIE0A);
} else {
// do not call the interrupt function COMPA anymore
TIMSK0 &= ~_BV(OCIE0A);
}
}
void setup() {
Serial.begin(9600);
Serial.print("Flow sensor test!");
lcd.begin(16, 2);
pinMode(FLOWSENSORPIN, INPUT);
digitalWrite(FLOWSENSORPIN, HIGH);
lastflowpinstate = digitalRead(FLOWSENSORPIN);
useInterrupt(true);
}
void loop() // run over and over again
{
lcd.setCursor(0, 0);
lcd.print("Pulses:"); lcd.print(pulses, DEC);
lcd.print(" Hz:");
lcd.print(flowrate);
//lcd.print(flowrate);
Serial.print("Freq: "); Serial.println(flowrate);
Serial.print("Pulses: "); Serial.println(pulses, DEC);
// if a plastic sensor use the following calculation
// Sensor Frequency (Hz) = 7.5 * Q (Liters/min)
// Liters = Q * time elapsed (seconds) / 60 (seconds/minute)
// Liters = (Frequency (Pulses/second) / 7.5) * time elapsed (seconds) / 60
// Liters = Pulses / (7.5 * 60)
float liters = pulses;
liters /= 7.5;
liters /= 60.0;
/*
// if a brass sensor use the following calculation
float liters = pulses;
liters /= 8.1;
liters -= 6;
liters /= 60.0;
*/
Serial.print(liters); Serial.println(" Liters");
lcd.setCursor(0, 1);
lcd.print(liters); lcd.print(" Liters ");
delay(100);
}
What do you guys think about this idea? Will this work?