rpm-count.ino

#include "LiquidCrystal.h"
#include "Timer.h"

Timer Count;
// rs, en, d4, d5, d6, d7
LiquidCrystal lcd(8, 9, 4, 5, 6, 7);

long rpmcount;
const int hallPin = 2;
int time_now = 0;


void setup()
{
  pinMode(hallPin,INPUT);
  lcd.begin(16, 2);
  lcd.print("RPM: ");
  lcd.setCursor(0,1);

  attachInterrupt(digitalPinToInterrupt(hallPin), rpmFunc, RISING);
  Count.every(5000, rpmCal);
}

void loop() {
  Count.update();
}

void rpmCal() {
  lcd.print(rpmcount*2*5);
  delay(1000);
  rpmcount = 0;
  clearLCDLine(1);
}

void rpmFunc()
{
  rpmcount++;
}

void clearLCDLine(int line){
 for(int n = 0; n < 12; n++) {
   lcd.setCursor(n,line);
   lcd.print(" ");
 }
 lcd.setCursor(0,line);
}