2 ms·An 80db piezo buzzer is $.13 and can operate on logic levels. No need to get fancyby dghlsakjg 4y agoAn 80db piezo buzzer is $.13 and can operate on logic levels. No need to get fancybecho 4y agoDeaf people exist.frankus 4y agoIt can also be hard to hear through e.g. a full-face helmet, or if you're (perhaps unwisely) wearing headphones.