Simon: Random Sequence

Part of the Projects section of Coddy's Arduino journey. Lesson 14 of 24.

Now the board takes its turn. The first time a button is let go, the game starts: the board picks four random colours, keeps them in an array, and plays them.

random(4) gives 0, 1, 2 or 3: one colour. A for loop fills the array. As in the reaction game, seed with micros() at the press, or every game plays the same colours:

randomSeed(micros());
for (int i = 0; i < 4; i++) {
  sequence[i] = random(4);
}

A second for loop plays the pattern: light a colour with its note, wait, turn it off, and wait again. The second wait matters when a colour comes twice: without it, red, red looks like one long red. The player only watches now, so delay() is fine.

for (int i = 0; i < 4; i++) {
  lightOn(sequence[i]);
  delay(400);
  lightOff(sequence[i]);
  delay(200);
}

A bool called playing remembers that the game has started, so only the first press starts it.

Challenge

Medium

Make the board play a pattern:

add int sequence[4]; and bool playing = false;
when a button is let go and playing is false: seed, fill the array with random(4), set playing to true, and play the pattern
the pattern: wait 500 ms, then each colour with its note for 400 ms, and 200 ms of quiet after it

Afterwards the buttons light and play as before. Press Run, press a button, then Check.

Try it yourself

// One entry per colour: red, green, blue, yellow
const int ledPins[4] = {9, 10, 11, 12};
const int buttonPins[4] = {2, 3, 4, 5};
const int notes[4] = {262, 330, 392, 523};  // C, E, G and high C
const int buzzerPin = 8;

int lastState[4] = {HIGH, HIGH, HIGH, HIGH};  // each button's last reading

// Light colour i and play its note.
void lightOn(int i) {
  digitalWrite(ledPins[i], HIGH);
  tone(buzzerPin, notes[i]);
}

// Turn colour i off and stop the sound.
void lightOff(int i) {
  digitalWrite(ledPins[i], LOW);
  noTone(buzzerPin);
}

void setup() {
  for (int i = 0; i < 4; i++) {
    pinMode(ledPins[i], OUTPUT);
    pinMode(buttonPins[i], INPUT_PULLUP);
  }
}

void loop() {
  for (int i = 0; i < 4; i++) {
    int state = digitalRead(buttonPins[i]);
    if (state == LOW && lastState[i] == HIGH) {  // pressed
      lightOn(i);
    }
    if (state == HIGH && lastState[i] == LOW) {  // let go
      lightOff(i);
    }
    lastState[i] = state;
  }
}

Test yourself

This lesson includes a short quiz. Start the lesson to answer it and track your progress.

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Practice on your own: Arduino playground