UP DOWN Counter mit Debounce

Hallo Forum
 Mein Promlem ist ein nicht funktionierender Counter, der unkontrolliert 
Rauf oder Runter zählt. Ein normaler code in dem selbstständig alle 
zahlen durchlaufen funktioniert.wenn ich aber mit den taster rauf oder 
runter switche springt er von eins auf drei oder vier, schaltet nicht 
runter oder reagiert überhaupt nicht!!
Fehler im Code oder Defektes board?
Hier mal mein Code:

#define BUTTON_DOWN 10
#define BUTTON_UP 12
#define BUTTON_RE 11

int ledPinA =  2;
int ledPinB =  3;
int ledPinC =  4;
int ledPinD =  5;
int ledPinE =  6;
int ledPinF =  7;
int ledPinG =  8;
int ledPinDP =  9;

int gear_down = 0;
int old_gear_down = 0;
int gear_up = 0;
int old_gear_up = 0;
int state = 0;
int gear = 1;
int RE = 1;
int old_RE = 0;

void setup()   {
  pinMode(BUTTON_DOWN, INPUT);
  pinMode(BUTTON_UP, INPUT);
  pinMode(BUTTON_RE,INPUT);

  pinMode(ledPinA, OUTPUT);
  pinMode(ledPinB, OUTPUT);
  pinMode(ledPinC, OUTPUT);
  pinMode(ledPinD, OUTPUT);
  pinMode(ledPinE, OUTPUT);
  pinMode(ledPinF, OUTPUT);
  pinMode(ledPinG, OUTPUT);
  pinMode(ledPinDP, OUTPUT);


  Serial.begin(9600);
}

void led0()
{
  digitalWrite(ledPinA, LOW);
  digitalWrite(ledPinB, LOW);
  digitalWrite(ledPinC, LOW);
  digitalWrite(ledPinD, LOW);
  digitalWrite(ledPinE, LOW);
  digitalWrite(ledPinF, LOW);
  digitalWrite(ledPinG, HIGH);
  digitalWrite(ledPinDP, HIGH);
}

void led1()
{
  digitalWrite(ledPinA, HIGH);
  digitalWrite(ledPinB, LOW);
  digitalWrite(ledPinC, LOW);
  digitalWrite(ledPinD, HIGH);
  digitalWrite(ledPinE, HIGH);
  digitalWrite(ledPinF, HIGH);
  digitalWrite(ledPinG, HIGH);
  digitalWrite(ledPinDP, LOW);
}

void led2()
{
  digitalWrite(ledPinA, LOW);
  digitalWrite(ledPinB, LOW);
  digitalWrite(ledPinC, HIGH);
  digitalWrite(ledPinD, LOW);
  digitalWrite(ledPinE, LOW);
  digitalWrite(ledPinF, HIGH);
  digitalWrite(ledPinG, LOW);
  digitalWrite(ledPinDP, HIGH);
}

void led3()
{
  digitalWrite(ledPinA, LOW);
  digitalWrite(ledPinB, LOW);
  digitalWrite(ledPinC, LOW);
  digitalWrite(ledPinD, LOW);
  digitalWrite(ledPinE, HIGH);
  digitalWrite(ledPinF, HIGH);
  digitalWrite(ledPinG, LOW);
  digitalWrite(ledPinDP, HIGH);
}

void led4()
{
  digitalWrite(ledPinA, HIGH);
  digitalWrite(ledPinB, LOW);
  digitalWrite(ledPinC, LOW);
  digitalWrite(ledPinD, HIGH);
  digitalWrite(ledPinE, HIGH);
  digitalWrite(ledPinF, LOW);
  digitalWrite(ledPinG, LOW);
  digitalWrite(ledPinDP, HIGH);
}

void led5()
{
  digitalWrite(ledPinA, LOW);
  digitalWrite(ledPinB, HIGH);
  digitalWrite(ledPinC, LOW);
  digitalWrite(ledPinD, LOW);
  digitalWrite(ledPinE, HIGH);
  digitalWrite(ledPinF, LOW);
  digitalWrite(ledPinG, LOW);
  digitalWrite(ledPinDP, HIGH);
}

void led6()
{
  digitalWrite(ledPinA, LOW);
  digitalWrite(ledPinB, HIGH);
  digitalWrite(ledPinC, LOW);
  digitalWrite(ledPinD, LOW);
  digitalWrite(ledPinE, LOW);
  digitalWrite(ledPinF, LOW);
  digitalWrite(ledPinG, LOW);
  digitalWrite(ledPinDP, HIGH);
}

void led7()
{
  digitalWrite(ledPinA, LOW);
  digitalWrite(ledPinB, LOW);
  digitalWrite(ledPinC, LOW);
  digitalWrite(ledPinD, HIGH);
  digitalWrite(ledPinE, HIGH);
  digitalWrite(ledPinF, HIGH);
  digitalWrite(ledPinG, HIGH);
  digitalWrite(ledPinDP, HIGH);
}

void led8()
{
  digitalWrite(ledPinA, LOW);
  digitalWrite(ledPinB, LOW);
  digitalWrite(ledPinC, LOW);
  digitalWrite(ledPinD, LOW);
  digitalWrite(ledPinE, LOW);
  digitalWrite(ledPinF, LOW);
  digitalWrite(ledPinG, LOW);
  digitalWrite(ledPinDP, HIGH);
}

void led9()
{
  digitalWrite(ledPinA, LOW);
  digitalWrite(ledPinB, LOW);
  digitalWrite(ledPinC, LOW);
  digitalWrite(ledPinD, LOW);
  digitalWrite(ledPinE, HIGH);
  digitalWrite(ledPinF, LOW);
  digitalWrite(ledPinG, LOW);
  digitalWrite(ledPinDP, HIGH);
}

void ledDP()
{
  digitalWrite(ledPinA, HIGH);
  digitalWrite(ledPinB, HIGH);
  digitalWrite(ledPinC, HIGH);
  digitalWrite(ledPinD, HIGH);
  digitalWrite(ledPinE, HIGH);
  digitalWrite(ledPinF, HIGH);
  digitalWrite(ledPinG, HIGH);
  digitalWrite(ledPinDP, LOW);
}

void ledRE()
{
  digitalWrite(ledPinA, HIGH);
  digitalWrite(ledPinB, HIGH);
  digitalWrite(ledPinC, HIGH);
  digitalWrite(ledPinD, HIGH);
  digitalWrite(ledPinE, LOW);
  digitalWrite(ledPinF, HIGH);
  digitalWrite(ledPinG, LOW);
  digitalWrite(ledPinDP, LOW);
}

void setLed(int number)
{
  switch (number) {
    case 0:
      ledDP();
      break;
    case 1:
      led1();
      break;
    case 2:
      led2();
      break;
    case 3:
      led3();
      break;
    case 4:
      led4();
      break;
    case 5:
      led5();
      break;
    case 6:
      led6();
      break;
    case 7:
      led7();
      break;
    case 8:
      led8();
      break;
    case 9:
      led9();
      break;
  }
}


void oldloop()
{
  ledDP();
  delay(1000);
  led0();
  delay(1000);
  led1();
  delay(1000);
  led2();
  delay(1000);
  led3();
  delay(1000);
  led4();
  delay(1000);
  led5();
  delay(1000);
  led6();
  delay(1000);
  led7();
  delay(1000);
  led8();
  delay(1000);
  led9();
  delay(1000);
}

void loop()
{
    gear_up = digitalRead(BUTTON_UP);
    if ((gear_up == HIGH) && (old_gear_up == LOW)) {
      gear += 1;
      Serial.print("gear number:  ");
      Serial.println(gear, DEC);
      delay(100);
    }
    old_gear_up = gear_up;

    gear_down = digitalRead(BUTTON_DOWN);
    if ((gear_down == HIGH) && (old_gear_down == LOW)) {
      gear -= 1;
      Serial.print("gear number:  ");
      Serial.println(gear, DEC);
      delay(100);
    }
    old_gear_down = gear_down;

    if (gear >= 6) {
      gear = 6;
    }
    if (gear <= 1) {
      gear = 1;
    }

   {
    RE = digitalRead(RE);
    if ((RE == HIGH) && (old_RE == LOW)) {
      gear = RE;
      Serial.print("gear number:  ");
      Serial.println(gear, DEC);
      delay(100);
    }
    }
    setLed(gear);
}



Bitte um Hilfe