diff --git a/ampel-firmware/ampel-firmware.ino b/ampel-firmware/ampel-firmware.ino
index e8dccfbb3933bdb62579c8cec9edab24e306a22e..39e6362e1efa4b31550d402b4a5ac73448d0f3dc 100644
--- a/ampel-firmware/ampel-firmware.ino
+++ b/ampel-firmware/ampel-firmware.ino
@@ -71,9 +71,11 @@ void loop() {
   // Check if air is good enough
   if (co2 <= 1000) {
     // Light the LED green if CO2 ppm is low
+    //                   position, red, green, blue
     led_ring.setPixelColor(which_led, 0, 255, 0);
   } else {
     // Red otherwise.
+    //                   position, red, green, blue
     led_ring.setPixelColor(which_led, 255, 0, 0);
   }
   led_ring.show();