3+5_2. 내부 풀업 + 부저

void setup() {

pinMode(2, INPUT_PULLUP);

pinMode(3, INPUT_PULLUP);

pinMode(4, INPUT_PULLUP);

}

void loop() {

if ( !(digitalRead(2)) == HIGH) {

 tone(8, 262, 100);

 }

if ( !(digitalRead(3)) == HIGH) {

 tone(8, 294, 100);

 }

if ( !(digitalRead(4)) == HIGH) {

 tone(8, 330, 100);

 }

}