Swiss scientists built tiny flying robots without motors or batteries, using sound waves to generate thrust and steer them through the air |
Engineers in Switzerland have worked out how to make miniature robots fly and steer without a single motor, magnet or battery on board. Researchers at the École Polytechnique Fédérale de Lausanne have built hollow structures that turn sound waves directly into thrust, drawing on Helmholtz resonance, the same physics behind the low hum produced by…