Reading and writing to a single digital pin

Using Arduino Programming Questions
40

@OOO

I think your approach is interesting and am looking forward to seeing it work.

You need to avoid reading the button/led that you have already turned on.

Maybe something like this (compiled but not tested)

/*
    "Radio Buttons"
    When a button is pressed, latch its own LED on, and turn all the others off
*/
const int nButtons=3;
int buttons[]= { 7, 12, 14 };  // each "button" is a button/led pair
int currentOn = 0;

void latch( int onPin)
{
    // turn onPin on, 
    digitalWrite( onPin, LOW);
    pinMode( onPin, OUTPUT);

    // if there is an other pin on, turn it off
    if (currentOn > 0) 
    {
       pinMode( currentOn, INPUT);
       digitalWrite( currentOn, HIGH);  // pullup
    }
}

void loop()
{
  for (int i=0; i< nButtons; i++)
  {   
      // read all but the currenly-on button
      if ( buttons[i] != currentOn && digitalRead( buttons[i])== LOW)  // active LOW
      {
          latch( buttons[i]);
          currentOn = buttons[i];
          break;
      }
  }
}

Cheers,
John