int brightness = 0;    // уставливаем начально значение яркости

int fadeAmount = 5;

int sensorPIR1 = 13;


void setup()  {
  // устанваливаем пин 9 в режим выхода
  pinMode(9, OUTPUT);
}


void loop()  {

analogWrite(9, brightness);
    if (brightness > 255 || brightness == 255) {
    brightness = 255;
    }

    else if (digitalRead(sensorPIR1) == HIGH) {
    brightness = brightness + fadeAmount;
    }


    if (brightness < 0 || brightness == 0) {
    brightness = 0;
    }

    else if (digitalRead(sensorPIR1) == LOW) {
    brightness = brightness - fadeAmount;
    }

delay(30);

}