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Variation as requested.

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edited Jul 19, 2018 at 19:53

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#include <Bounce2.h>

const int     BUTTON_COUNT = 4;
const int16_t DEBOUNCE_DELAY = 50;
const uint8_t buttonPins[BUTTON_COUNT] = {2, 4, 6, 8};
const uint8_t ledPins[BUTTON_COUNT] = {3, 5, 7, 9};

Bounce buttons[BUTTON_COUNT];
uint8_t ledStates[BUTTON_COUNT];

void setup() {
    for (int i = 0; i < BUTTON_COUNT; i++) {
        buttons[i].attach(buttonPins[i], INPUT);
        buttons[i].interval(DEBOUNCE_DELAY);
        pinMode(ledPins[i], OUTPUT);
        ledStates[i] = LOW;
        digitalWrite(ledPins[i], ledStates[i]);
    }
}

void loop() {

    // Update the debouncers.
    for (int i = 0; i < BUTTON_COUNT; i++)
        buttons[i].update();

    // When the first button is pressed:
    if (buttons[0].rose()) {

        // Light up the first LED.
        digitalWrite(ledPins[0], HIGH);

        // and turn off all the others.
        for (int i = 1; i < BUTTON_COUNT; i++) {
            ledStates[i] = LOW;
            digitalWrite(ledPins[i], ledStates[i]);
        }
    }

    // When the first button is released:
    if (buttons[0].fell()) {

        // turn off the first LED.
        digitalWrite(ledPins[0], LOW);
    }

    // When any other button is pressed:
    for (int i = 1; i < BUTTON_COUNT; i++) if (buttons[i].rose()) {

        // Toggle its state.
        ledStates[i] = !ledStates[i];
        digitalWrite(ledPins[i], ledStates[i]);
    }
}

Edit: In order for the first button to only turn off LEDs 1 and 2, the lines

// and turn off all the others.
for (int i = 1; i < BUTTON_COUNT; i++) {
    ledStates[i] = LOW;
    digitalWrite(ledPins[i], ledStates[i]);
}

should be replaced by:

// and turn off LEDs 1 and 2.
for (int i = 1; i <= 2; i++) {
    ledStates[i] = LOW;
    digitalWrite(ledPins[i], ledStates[i]);
}

#include <Bounce2.h>

const int     BUTTON_COUNT = 4;
const int16_t DEBOUNCE_DELAY = 50;
const uint8_t buttonPins[BUTTON_COUNT] = {2, 4, 6, 8};
const uint8_t ledPins[BUTTON_COUNT] = {3, 5, 7, 9};

Bounce buttons[BUTTON_COUNT];
uint8_t ledStates[BUTTON_COUNT];

void setup() {
    for (int i = 0; i < BUTTON_COUNT; i++) {
        buttons[i].attach(buttonPins[i], INPUT);
        buttons[i].interval(DEBOUNCE_DELAY);
        pinMode(ledPins[i], OUTPUT);
        ledStates[i] = LOW;
        digitalWrite(ledPins[i], ledStates[i]);
    }
}

void loop() {

    // Update the debouncers.
    for (int i = 0; i < BUTTON_COUNT; i++)
        buttons[i].update();

    // When the first button is pressed:
    if (buttons[0].rose()) {

        // Light up the first LED.
        digitalWrite(ledPins[0], HIGH);

        // and turn off all the others.
        for (int i = 1; i < BUTTON_COUNT; i++) {
            ledStates[i] = LOW;
            digitalWrite(ledPins[i], ledStates[i]);
        }
    }

    // When the first button is released:
    if (buttons[0].fell()) {

        // turn off the first LED.
        digitalWrite(ledPins[0], LOW);
    }

    // When any other button is pressed:
    for (int i = 1; i < BUTTON_COUNT; i++) if (buttons[i].rose()) {

        // Toggle its state.
        ledStates[i] = !ledStates[i];
        digitalWrite(ledPins[i], ledStates[i]);
    }
}

#include <Bounce2.h>

const int     BUTTON_COUNT = 4;
const int16_t DEBOUNCE_DELAY = 50;
const uint8_t buttonPins[BUTTON_COUNT] = {2, 4, 6, 8};
const uint8_t ledPins[BUTTON_COUNT] = {3, 5, 7, 9};

Bounce buttons[BUTTON_COUNT];
uint8_t ledStates[BUTTON_COUNT];

void setup() {
    for (int i = 0; i < BUTTON_COUNT; i++) {
        buttons[i].attach(buttonPins[i], INPUT);
        buttons[i].interval(DEBOUNCE_DELAY);
        pinMode(ledPins[i], OUTPUT);
        ledStates[i] = LOW;
        digitalWrite(ledPins[i], ledStates[i]);
    }
}

void loop() {

    // Update the debouncers.
    for (int i = 0; i < BUTTON_COUNT; i++)
        buttons[i].update();

    // When the first button is pressed:
    if (buttons[0].rose()) {

        // Light up the first LED.
        digitalWrite(ledPins[0], HIGH);

        // and turn off all the others.
        for (int i = 1; i < BUTTON_COUNT; i++) {
            ledStates[i] = LOW;
            digitalWrite(ledPins[i], ledStates[i]);
        }
    }

    // When the first button is released:
    if (buttons[0].fell()) {

        // turn off the first LED.
        digitalWrite(ledPins[0], LOW);
    }

    // When any other button is pressed:
    for (int i = 1; i < BUTTON_COUNT; i++) if (buttons[i].rose()) {

        // Toggle its state.
        ledStates[i] = !ledStates[i];
        digitalWrite(ledPins[i], ledStates[i]);
    }
}

Edit: In order for the first button to only turn off LEDs 1 and 2, the lines

// and turn off all the others.
for (int i = 1; i < BUTTON_COUNT; i++) {
    ledStates[i] = LOW;
    digitalWrite(ledPins[i], ledStates[i]);
}

should be replaced by:

// and turn off LEDs 1 and 2.
for (int i = 1; i <= 2; i++) {
    ledStates[i] = LOW;
    digitalWrite(ledPins[i], ledStates[i]);
}

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answered Jul 19, 2018 at 8:42

Edgar Bonet

45.2k
4
42
81

First thing, you need to debounce your buttons. The fact that you declared the (unused) variable debounceDelay suggests you have though about debouncing, but you did not implement it.

Next thing, you should look for button press and release events. That's when the button pin changes state from LOW to HIGH or vice versa. It is not enough to check whether the pin is HIGH or LOW, you have to check for the changes in state. This is usually called edge detection.

With enough effort, you could probably do that yourself. However, to make your life easier, you can use a debouncing library that does edge detection, such as the quite popular Bounce2. This library provides, for each button it debounces, a rose() method that tells you when the input signal rose (i.e. transitioned from LOW to HIGH) and a fell() method that tells you when it fell (transitioned HIGH → LOW). Using these methods, your problem can be coded in a fair natural way. For example (not tested):

#include <Bounce2.h>

const int     BUTTON_COUNT = 4;
const int16_t DEBOUNCE_DELAY = 50;
const uint8_t buttonPins[BUTTON_COUNT] = {2, 4, 6, 8};
const uint8_t ledPins[BUTTON_COUNT] = {3, 5, 7, 9};

Bounce buttons[BUTTON_COUNT];
uint8_t ledStates[BUTTON_COUNT];

void setup() {
    for (int i = 0; i < BUTTON_COUNT; i++) {
        buttons[i].attach(buttonPins[i], INPUT);
        buttons[i].interval(DEBOUNCE_DELAY);
        pinMode(ledPins[i], OUTPUT);
        ledStates[i] = LOW;
        digitalWrite(ledPins[i], ledStates[i]);
    }
}

void loop() {

    // Update the debouncers.
    for (int i = 0; i < BUTTON_COUNT; i++)
        buttons[i].update();

    // When the first button is pressed:
    if (buttons[0].rose()) {

        // Light up the first LED.
        digitalWrite(ledPins[0], HIGH);

        // and turn off all the others.
        for (int i = 1; i < BUTTON_COUNT; i++) {
            ledStates[i] = LOW;
            digitalWrite(ledPins[i], ledStates[i]);
        }
    }

    // When the first button is released:
    if (buttons[0].fell()) {

        // turn off the first LED.
        digitalWrite(ledPins[0], LOW);
    }

    // When any other button is pressed:
    for (int i = 1; i < BUTTON_COUNT; i++) if (buttons[i].rose()) {

        // Toggle its state.
        ledStates[i] = !ledStates[i];
        digitalWrite(ledPins[i], ledStates[i]);
    }
}