What it is
Sound Alerts is a home convenience tool for Deaf and hard-of-hearing people. It listens through your device's microphone for four sounds, doorbell, knocking, a baby crying, and a dog barking, and flashes a big visual alert on your screen (plus your phone's vibration) when it hears one. You can teach it your own doorbell's exact chime, and a built-in test mode checks the listener against synthesized sounds. Everything runs on your device: no audio is recorded, uploaded, or sent anywhere.
Honest limits
- This is a home practice and convenience tool, not a safety device. Never rely on it for smoke alarms, carbon monoxide alarms, or any emergency.
- It can miss sounds and misidentify them. Background noise, distance from the sound, and unusual chimes all make it less reliable. It only works while this app is open and listening.
- It is not a substitute for certified visual or vibrating smoke and carbon monoxide alarms. Those exist because they are tested and regulated; this app is neither.
- Feedback is automatic and can be wrong. The "test the listener" mode shows you exactly what it hears and what it misses, so you can judge it honestly.
Resources
- National Association of the Deaf (NAD): the US civil rights organization for Deaf and hard-of-hearing people, with resources on rights, technology, and community.
- Hearing Loss Association of America (HLAA): the leading US consumer organization for people with hearing loss, with support, advocacy, and information on assistive technology including alerting devices.
How the sounds are checked
- Doorbell: two clear chimes, the second the same pitch or lower than the first (ding-dong). A single chime does not count.
- Knocking: two or more short, sharp thumps close together. A single thump does not count.
- Baby crying: a sustained voiced sound whose pitch wobbles up and down in a regular rhythm. Steady talking does not count.
- Dog barking: two or more short, rough bursts with gaps between. One long rough sound does not count.
- My doorbell: your own recording, matched against its chime pattern (pitches, lengths, gaps). A different chime does not count.
The detector is a small hand-written spectral analyzer, not a neural network: it measures pitch, noisiness, and timing directly from the microphone signal. That keeps it tiny (the whole app is under a megabyte) and fully explainable, and it means every rule can be tested with synthesized sounds, including the wrong versions that must be rejected.