A small drone can now move through darkness by gently touching its surroundings with two long artificial whiskers.
The idea comes directly from rats and moles. In the dark, their whiskers allow them to sense nearby objects and follow a wall. Researchers adapted this principle to a drone weighing just 44.1 g. Two flexible rods positioned at the front touch obstacles to prevent the body of the device from colliding with them.
The 44.1 g Crazyflie drone equipped with two artificial whiskers, showing the tactile sensor and its biological inspiration.
Credit: Ye et al., Nature Communications (2026), CC BY 4.0.
Each whisker is 20 cm long and only 0.4 mm in diameter. When it bends against an object, tiny sensors at its base measure the pressure variations caused by the contact. The drone can then estimate how far away the obstacle is. The entire detection system weighs 3.2 g.
Contact therefore does more than simply signal that a wall is there. The drone obtains an estimate of the obstacle’s position with an accuracy of a few millimeters. It then adjusts its trajectory in real time. The researchers also carefully selected the whiskers’ orientation, because friction against a surface can destabilize such a lightweight device.
The tests show what this approach makes possible in practice. In complete darkness, the drone can move forward until it encounters a wall, then follow it. It also navigated a course containing several transparent panels. These surfaces can be difficult to detect with some systems that rely on light.
Tests of different artificial-whisker orientations while the drone followed a wall.
Credit: Ye et al., Nature Communications (2026), CC BY 4.0.
More surprisingly, the device can gradually build a representation of an enclosed space by exploring its walls through contact. It does not need to send its measurements to an external computer. Information processing, decision-making, and control are carried out directly on board, using a microcontroller with just 192 KB of RAM.
This method does not necessarily replace cameras or distance sensors. It mainly provides another way to perceive the environment when vision becomes unreliable. A small drone could therefore continue detecting obstacles in darkness, smoke, or certain confined spaces. Its low mass also allows it to reach places where a heavier device would be less suitable.
The technique nevertheless has limitations. Tests on flexible surfaces caused oscillations, particularly because of folds and friction.
The researchers envision this tactile perception for search and rescue, inspection, and the exploration of difficult-to-access locations. It remains to be determined how it will perform in real-world environments.