How it works: The alarm uses a 16,000 Hz (16 kHz) sawtooth wave. Most adults over 25 gradually lose the ability to hear frequencies this high (a natural process called presbycusis), while children and teens can hear it clearly. This means the alarm signals students without disturbing the teacher.

Is it safe? At the low volume output by a phone or laptop speaker, this tone is well below harmful levels. There is no evidence linking tones at this frequency and volume to hearing damage or seizures. For reference, the sound pressure level from a device speaker at this gain is far lower than normal classroom conversation (~60 dB).

⚠️ Auditory sensitivity: Students with autism spectrum disorder, sensory processing differences, or auditory hypersensitivity may experience this tone as distressing or painful, even at low volumes. If you have students with these conditions, consider using the visual-only alerts (mascot/meter) and keeping the audio alarm disabled.

The alarm is never harmful at these output levels, but it can be unpleasant by design — that’s how it works as a deterrent. Use your professional judgment for your classroom.