Dark rugs confuse the retractable mop sensor

The retractable mop feature on newer robot vacuums is clever in theory: lift the mop pad when it hits carpet so you don’t drag a wet pad across your rug, lower it back down on hard floors. In practice, it mostly works — except on dark-colored rugs.

The cliff sensors that detect drop-offs use infrared light, and dark surfaces absorb more of that light instead of reflecting it back. The robot sometimes misreads a dark rug as a drop-off and refuses to drive onto it. It’s a minor quirk — the vacuum will just skip that rug altogether — but it’s worth knowing about if your home has dark, low-pile rugs that you’d otherwise expect the robot to handle.

Not a dealbreaker, but a reminder that optical sensors have blind spots, literally.