Fine-tuned acoustic waves can knock drones out of the sky

AS CHILDREN everywhere are delighted to learn in science class, sound can shatter glass. Might it also be possible, then, to use acoustic waves to disrupt the electromechanical sensors that drones require to fly? To find out, four engineering students at the University of Toronto repurposed small car speakers to cobble together a contraption “for blasting a drone with sound”, as one of them, Michael Acquaviva, puts it. It worked in early tests, though only at close range. Drones 50cm away wobbled. At 25cm, they crashed.

Come the spring of 2024, after the kit’s power supply was beefed up and the speakers were replaced with transducers capable of producing ultrasonic waves, the system was entered in a counter-drone competition held by Canada’s defence department. The team’s design tied for second prize, winning C$375,000 ($262,000). Its members founded a small startup, Prandtl Dynamics, that now plans to have a prototype the size of a carry-on suitcase suitable for battlefield use by June. The desired initial attack range is 100 metres.