I've always liked the light indications of modern cnc machines (red: error , green: working , orange/yellow: paused, manual operation etc.) and wanted to implement this feature in my toolchanger design. I'm using adressable LED's so it possible not just to show the overall status with red, green and yellow. The 16bit LED-bar allows to show the printing procress in 6.25% time increments. Therefore the LED's switch incrementally from white to green (based on the estimated print time).

As you can see the actual status bar at the front is significantly longer than the actual 16bit-LED (2x 8Bit WS2812). Therefore I had to test the homogeneity with the brightness.

For proof of concept I've used paper and tape to see if the light ''channels'' even work.

This picture shows the mentioned problem with the homogeinity. The LED's in the middle have the shortest way and therefore shine the brightest. The outer LED's have a quite long and curved channel to pass before hitting the diffusor.

To improve the homogeinity I've adressed the LED's individually and set the brighness for better appearance.

for (int i = 0; i < NUMPIXELS; i++)
  {
    if (i <= 2 || i > 12)
    {
      pixels.setPixelColor(i, pixels.Color(255, 255, 255)); 
      pixels.show();                                        // This sends the updated pixel color to the hardware.
      delay(delayval);                                      // Delay for a period of time (in milliseconds).
    }
    else
    {
      if (i == 3 || i == 12)
      {
        pixels.setPixelColor(i, pixels.Color(130, 130, 130)); 
        pixels.show();                                        // This sends the updated pixel color to the hardware.
        delay(delayval);                                      // Delay for a period of time (in milliseconds).
      }
      else
      {
        if (i == 4 || i == 11)
        {
          pixels.setPixelColor(i, pixels.Color(100, 100, 100)); 
          pixels.show();                                        // This sends the updated pixel color to the hardware.
          delay(delayval);                                      // Delay for a period of time (in milliseconds).
        }
        else
        {
          if (i == 5 || i == 10)
          {
            pixels.setPixelColor(i, pixels.Color(50, 50, 50)); 
            pixels.show();                                     // This sends the updated pixel color to the hardware.
            delay(delayval);                                   // Delay for a period of time (in milliseconds).
          }
          else
          {
            if (i == 6 || i == 9)
            {
              pixels.setPixelColor(i, pixels.Color(40, 40, 40)); 
              pixels.show();                                     // This sends the updated pixel color to the hardware.
              delay(delayval);                                   // Delay for a period of time (in milliseconds).
            }
            else
            {
              if (i == 7 || i == 8)
              {
                pixels.setPixelColor(i, pixels.Color(30, 30, 30)); 
                pixels.show();                                     // This sends the updated pixel color to the hardware.
                delay(delayval);                                   // Delay for a period of time (in milliseconds).
              }
            }
          }
        }
      }
    }
  }
}

For the implementation in the Duet-Firmware I will write a class ''LED_Color'' and use the arduino Nano as a slave which just receives the task ''Green'' , ''Orange'', ''Red'' and ''Status''. The actual code isn't done yet.