Škoda DuoBell: a bike bell that beats noise-cancelling headphones — shared open source

The classic bicycle bell is roughly a hundred years old, and the world around it changed: pedestrians now cross streets wearing noise-cancelling headphones whose algorithms cancel the bell's ding before it reaches the ear. In London, where cyclists were expected to outnumber drivers for the first time in 2026, Transport for London recorded a 24% rise in bike–pedestrian collisions in 2024 — and Škoda, a brand with cycling roots dating to 1895, made that its brief.

Working with AMV BBDO, PHD Media's innovation team, Unit9 and acousticians from the University of Salford, Škoda ran one of the first studies of how ANC technology affects warning-bell audibility. The researchers identified a narrow frequency band between 750Hz and 780Hz that consistently penetrates ANC filters — a 'safety gap'. The mechanical DuoBell adds a second resonator tuned higher and a striking mechanism that produces rapid, irregular impacts, generating sound designed to fool the ANC algorithms.

In controlled testing, most participants heard the DuoBell up to five seconds earlier and up to 22 metres sooner than a standard bell through active noise cancellation. A two-week trial with a fleet of Deliveroo riders refined the final prototype, and Škoda published the findings in an open-source whitepaper, deliberately giving the technology away so city planners, manufacturers and cyclists can build or adopt it. At Cannes Lions 2026 the work took Silver in Health & Wellness and Bronze in Audio & Radio.