Untitled

#include <Wire.h>
#include <SoftwareSerial.h>
#include "LowPower.h"

const byte rtcPin = 19; //interrupt from RTC
int rpm = 0;

void pin19Interrupt(void) {
    rpm++;
}



void setup() {
  Serial.begin(9600);

  pinMode(rPin, INPUT);
  pinMode(wPin, INPUT);
  pinMode(rtcPin, INPUT);
}

void loop() {

  
  Serial.println("Entering sleep mode");

  attachInterrupt(RTCINT, pin19Interrupt, FALLING); //rtc
  
  LowPower.powerDown(SLEEP_FOREVER, ADC_OFF, BOD_OFF);

  delay(1);

}