//ODBIERAJĄCY

int ledPin[] = {0,1,2,3,4,5,6,7};
int buttonState=0;

void setup()
 {
   Serial.begin(9600);
   pinMode(dA0, INPUT_PULLUP);
   for (int i =0;i<=7;i++)
   {
     pinMode(ledPin[i], OUTPUT);
   }
 }

void loop()
 {

   int counter=0;
   int suma;
   buttonState=digitalRead(dA0);
   if(buttonState==LOW){
      // Serial.println("ok");
   }else{
     suma=0;
     int k=1;
        delay(1500);
       for(int i=0; i<8;++i){
        counter=digitalRead(dA0);

        if(counter==LOW){

         suma=suma+k;
        }
        k*=2;

        Serial.println(suma);
        delay(1000);
      }
   displayBinary(suma);
  // Serial.println("ok");
   //delay(8000);
 }


 }

void displayBinary(byte numToShow)
 {
   for (int i =0;i<=7;i++)
   {
     if (bitRead(numToShow, i)==1)
     {
       digitalWrite(ledPin[i], LOW);
     }
     else
     {
       digitalWrite(ledPin[i], HIGH);
     }
   }

 }


Program wysyłający :

//////////////////////////////////////////////////////////////////////////////////////////////////

const int time = 1000;

int buttonState = 0;

void setup() {
  pinMode(dB0, OUTPUT);
  pinMode(dB1,OUTPUT);

  Serial.begin(9600);
  pinMode(dA0, INPUT_PULLUP);
}


int K = 85;
int L = 85;
void loop(){


  buttonState = digitalRead(dA0);

  if (buttonState == LOW) {
    L++;

    digitalWrite(dB0, HIGH);
    digitalWrite(dB1, HIGH);
    delay(time);
    K = L;
    for( int i = 0; i <8;i++){

         int bit = 0x01 & K;
         K = K >> 1;

         if( bit == 1) {
             digitalWrite(dB0, LOW);
             digitalWrite(dB1, LOW);
             delay(time);
         } else{
            digitalWrite(dB0, HIGH);
            digitalWrite(dB1, HIGH);
            delay(time);
         }
  }
  } else {

     digitalWrite(dB0, LOW);
     digitalWrite(dB1, LOW);
     delay(time);
  }
}