Instead of using sophisticated sensors to detect their surroundings and navigate safely, drones and robots could listen for reflections of their own mechanical noises.

The whirring, squeaking or clicking created by robots’ wheels, joints and motors are usually undesirable, and engineers work hard to minimise them. But a research team has found that they can be useful as part of an echolocation system to aid navigation and avoid crashes.

Most robots, whether they walk, roll or fly create some sort of background noise. Flying drones, in particular, are extremely noisy. Jesper Rindom Jensen at Aalborg University in Denmark and his colleagues suggest robots …