pro_mini_piano.ino

#include "LowPower.h"

#define TONE_C 262
#define TONE_D 294
#define TONE_E 330
#define TONE_F 349
#define TONE_G 392
#define TONE_A 440
#define TONE_B 493

#define PIN_C 8
#define PIN_D 7
#define PIN_E 6
#define PIN_F 5
#define PIN_G 4
#define PIN_A 3
#define PIN_B 2

#define PIN_BUZZ 11

#define IDLE_SLEEP 5000

volatile unsigned long idleMs = 0, lastIdle = 0;

void wakeUp() {
    lastIdle = millis();
}

void setup() {
  pinMode(LED_BUILTIN, OUTPUT);
  pinMode(PIN_C, INPUT);
  digitalWrite(PIN_C,HIGH);
  pinMode(PIN_D, INPUT);
  digitalWrite(PIN_D,HIGH);
  pinMode(PIN_E, INPUT);
  digitalWrite(PIN_E,HIGH);
  pinMode(PIN_F, INPUT);
  digitalWrite(PIN_F,HIGH);
  pinMode(PIN_G, INPUT);
  digitalWrite(PIN_G,HIGH);
  pinMode(PIN_A, INPUT);
  digitalWrite(PIN_A,HIGH);
  pinMode(PIN_B, INPUT);
  digitalWrite(PIN_B,HIGH);
  digitalWrite(LED_BUILTIN,LOW);
}

void loop() {

  if (idleMs > IDLE_SLEEP) {
    attachInterrupt(0, wakeUp, LOW);
    LowPower.powerDown(SLEEP_FOREVER, ADC_OFF, BOD_OFF);
  } else {
    LowPower.idle(SLEEP_FOREVER, ADC_OFF, TIMER2_OFF, TIMER1_OFF, TIMER0_ON, 
                SPI_OFF, USART0_OFF, TWI_OFF);
  }

  detachInterrupt(0);
  
  while(digitalRead(PIN_C) == LOW) {
    tone(PIN_BUZZ,TONE_C);
    digitalWrite(LED_BUILTIN,HIGH);
    lastIdle = millis();
  }
  while(digitalRead(PIN_D) == LOW) {
    tone(PIN_BUZZ,TONE_D);
    digitalWrite(LED_BUILTIN,HIGH);
    lastIdle = millis();
  }
  while(digitalRead(PIN_E) == LOW) {
    tone(PIN_BUZZ,TONE_E);
    digitalWrite(LED_BUILTIN,HIGH);
    lastIdle = millis();
  }
  while(digitalRead(PIN_F) == LOW) {
    tone(PIN_BUZZ,TONE_F);
    digitalWrite(LED_BUILTIN,HIGH);
    lastIdle = millis();
  }
  while(digitalRead(PIN_G) == LOW) {
    tone(PIN_BUZZ,TONE_G);
    digitalWrite(LED_BUILTIN,HIGH);
    lastIdle = millis();
  }
  while(digitalRead(PIN_A) == LOW) {
    tone(PIN_BUZZ,TONE_A);
    digitalWrite(LED_BUILTIN,HIGH);
    lastIdle = millis();
  }
  while(digitalRead(PIN_B) == LOW) {
    tone(PIN_BUZZ,TONE_B);
    digitalWrite(LED_BUILTIN,HIGH);
    lastIdle = millis();
  }

  noTone(PIN_BUZZ);
  
  digitalWrite(LED_BUILTIN,LOW);

  idleMs = millis() - lastIdle;

}