if (mm_per_s) //is the board moving?
    {
        //moving the dot
        nextLED = LED_ABSTAND / mm_per_s;
        if ((micros() - nextLEDTimeOld) > nextLED)
        {
            leds_right[LED_position] += CHSV(255+turning, 255, 255);     //left LED
            leds_left[LED_position] += CHSV(255-turning, 255, 255);      //right LED
            LED_position++;

            nextLEDTimeOld = micros();
            FastLED.show();
            if (LED_position >= NUM_LEDS)       //wrap around
                LED_position = 0;
        }
    }

    //fading all LEDs
    if ((millis() - fadingTimeOld) > FADING_TIME)           //tail for the light, longe fading time = longer tail
    {
        for (int x = 0; x < NUM_LEDS; x++) {                  //decrease brightness of all LEDs
            leds_right[x].nscale8(180);
            leds_left[x].nscale8(180);
        }
        fadingTimeOld = millis();
        FastLED.show();
    }