Buttons pressed

Projects Programming
1

Hi all,

I wrote a simple script to check if there are buttons pressed. I added a pull down resistor between output of my tactile button and ground. The output of the buttons go to A0, A1, A2, ..., A6. At the input pin of the buttons I put 5V. My script does something very weird. When I press the button it keeps spamming the message "Button pressed". But when I uncomment the third line in this piece of code it suddenly works (which means it only prints "Button pressed" once for every time I press the button).

void checkButtons()
{
  Serial.println(buttonsPressed[0]);
  for(int i = 0; i < AMOUNT_BUTTONS; i++)
  {
    if(digitalRead(A0 + i) == HIGH)
    {
      if(buttonsHeld[i] == false)
      {
        buttonsHeld[i] = true;
        buttonsPressed[i] = true;
        Serial.println("Button pressed");
      }
      else
      {
        buttonsPressed[i] = false;
      }
    }
    else
    {
      buttonsHeld[i] = false;
      buttonsPressed[i] = false;
    }
  }
}

Nowhere other than in this piece of the code are buttonsPressed[] and buttonsHeld[] changed, printed or whatever. Except for the setup which sets all the values to false.

What the hell is happening here?

2

You need to post the complete program.

...R

3

Alright here it is. But it doesn't really add anything.

#define AMOUNT_BUTTONS 6

bool buttonsHeld[AMOUNT_BUTTONS], buttonsPressed[AMOUNT_BUTTONS];

void setup()
{
  Serial.begin(9600);

  delay(100);

  for(int i = 0; i < AMOUNT_BUTTONS; i++)
  {
    pinMode(A0 + i, INPUT);
    buttonsPressed[i] = false;
    buttonsHeld[i] = false;
  }
}

void loop()
{
  checkButtons();
}

void checkButtons()
{
  //  Serial.println(buttonsPressed[0]);
  for(int i = 0; i < AMOUNT_BUTTONS; i++)
  {
    if(digitalRead(A0 + i) == HIGH)
    {
      if(buttonsHeld[i] == false)
      {
        buttonsHeld[i] = true;
        buttonsPressed[i] = true;
        Serial.println("Button pressed");
      }
      else
      {
        buttonsPressed[i] = false;
      }
    }
    else
    {
      buttonsHeld[i] = false;
      buttonsPressed[i] = false;
    }
  }
}
4

Anteino:
Alright here it is. But it doesn't really add anything.

It adds a very important extra - now I know there is nothing else important. You would be surprised what gets left out.

I added a pull down resistor between output of my tactile button and ground.

That does not sound correct. I suspect the input is floating.

Either put a pull-up resistor on the pin (or better still use pinMode(pin, INPUT_PULLUP) ) and use the switch to pull it to GND. Or use a pull-down resistor on the pin and use the switch to pull it to 5v. The former is better as it is less likely to give rise to a short circuit is something comes adrift.

...R

5

Wait what, the arduino has onboard pullups? After all these years and I never knew. I feel like such an idiot right now :cry: