How to make a button stay on?

Projects Programming
5

Should be simple just to make an array that defines in which order the buttons should be pressed.

const byte PINCODE_LENGTH = 4;
const byte PINCODE[PINCODE_LEGTH] = {A0, A2, A1, A3};
const unsigned int PINCODE_TIMEOUT = 1000;
usigned long lastPincodePress = 0;
byte pincodeIndex = 0;

void loop()
{
  //Check if the pincode entering has timed out..
  unsigned long currentMilis = millis();
  if (currentMillis - lastPincodePress > PINCODE_TIMEOUT) pincodeIndex = 0;

  //Read next pincode button
  if (readButton(PINCODE[pincodeInbex])) {
    lastPinodePress = currentMillis;
    pincodeIndex++;
    if (pincodeIndex == PINCODE_LENGTH) {
      pincodeIndx = 0;
      //Successfully received the pincode!
    }
  }
}

bool readButton(byte btnPin) {
  byte hit=255, count=0;
  for (byte i = 0; i < PINODE_LENGTH; i++) if (digitalRead(PINCODE[i]) == HIGH) {
    hit = i;
    count++;
  }
  retrun (hit = btnPin) && (count == 1);
}

This will read the buttons in the sequence defined by "PINCODE". If no button is pressed for 1 second (1000 milliseconds), the pincode typing is reset to first button. Pseudocode and deliberate typos included for free - hope OP will think, not just copy! :wink: