# Sound Alerts: See the Sounds You Cannot Hear > Sound Alerts is a free web app for Deaf and hard-of-hearing people: it listens for your doorbell, knocking, a baby crying, or a dog barking and flashes a big visual alert. Teach it your own doorbell. On-device only, no account, not a safety device. *Interactive tool: enter your values at https://toollantern.win/sound-alerts-deaf-hard-of-hearing/ and results update instantly in your browser.* ## Frequently asked questions ### What is Sound Alerts? A free web app for Deaf and hard-of-hearing people that listens for four everyday sounds, doorbell, knocking, a baby crying, and a dog barking, and flashes a big full-screen visual alert naming the sound when it hears one. It is a home convenience tool, not a safety device. ### Which sounds does it detect? Four: doorbell (two clear chimes, ding-dong), knocking (two or more sharp thumps), a baby crying (a sustained wail with a regular pitch wobble), and a dog barking (short rough bursts). Each has a published rule, and near misses get a named hint instead of an alert. ### Can it learn my own doorbell? Yes. The Teach screen records three seconds while someone rings your doorbell, extracts the chime pattern (pitches, lengths, gaps), and stores only those numbers on your device. The audio is discarded. A Test button reports the match score any time. ### Is this a safety device? No, emphatically not. Sound Alerts is a home convenience tool. Never rely on it for smoke alarms, carbon monoxide alarms, or any emergency. It can miss sounds and misidentify them, and it only works while the app is open and listening. Use certified visual or vibrating alarms for safety. ### Does it record or upload my audio? No. Microphone audio is analyzed on your device and immediately discarded. Nothing is recorded, uploaded, or shared. The page security policy blocks connections to every outside server, and the Offline proof panel shows the live request log to prove it. ### How does it tell the sounds apart? A small hand-written analyzer measures pitch, noisiness, and timing from the microphone signal. A doorbell is two clear chimes; knocking is two or more sharp thumps; crying is a sustained voiced wobble; barking is rough bursts. Talking, background noise, single thumps, and single chimes are all explicitly rejected. ### What happens when it hears something? A full-screen card names the sound in large type, your phone vibrates where supported, and the alert is logged to an on-device history list with the time. Dismiss it with one tap. ### When does the microphone run? Only while you are on the listening screen. Leaving the screen, hiding the tab, or closing the page turns the mic fully off. Your browser's mic indicator shows whenever it runs, and a page cannot hide that indicator. ### Does it work offline? Yes, after your first visit. The app and the detector are saved on your device, so it works with no network at all. The Offline proof panel even lets you simulate a fully offline session. ### What is the test mode? Eight rounds where the app plays synthesized sounds through the real detector, mic bypassed, and you pick what was played from labeled options. Four rounds are tricky wrong versions (talking, noise, a single clap, a single chime) where the right answer is none of these. Wrong picks always show the named hint. ### Can I delete my data? Yes. Open Offline proof on the home page and press Delete all my data, or clear history and progress separately from the home and dashboard screens. Everything is stored only in your browser, on your device. ### Who is it for? Deaf and hard-of-hearing people who want a free, private convenience for everyday sounds at home: hearing the door, the baby, or the dog without wearing a hearing device every moment. For real support and community, the app links to the National Association of the Deaf and the Hearing Loss Association of America. --- Interactive version: https://toollantern.win/sound-alerts-deaf-hard-of-hearing/