Somnia: Teeth Grinding Bruxism

Somnia is a teeth grinding (bruxism) and snoring tracker. Leave the phone face down on the mattress by your pillow and it detects teeth grinding, snoring, sleep talking and coughing while you sleep, then estimates four sleep stages. It never saves audio, so nothing can be played back, and sound is analysed on the device only.

What it detects
Teeth grinding (bruxism), snoring, sleep talk and coughing are listed separately for each night, with the time and length of each event shown (see Free and Pro below for how many), and each night gets a snore score next to the sleep score. Loudness alone does not decide anything: a fan or an air conditioner running all night is not snoring. The cues are the balance of low and high frequencies, how noise-like the sound is, how fast it rises and how long it lasts, and for snores, whether the spacing between sounds matches a breathing cycle. Grinding teeth, sleep talking and coughing are separated the same way. A sensitivity slider sets how quiet a sound can be and still count. Detection is an estimate from sound, so a noisy room can confuse it.

A night with Somnia
23:40 - Face down on the mattress by your pillow. Pick one of 14 sleep sounds to fall asleep to: white noise, pink noise, brown noise, light and heavy rain, ocean waves, wind, a fan, an air conditioner, a night train, a stream, a waterfall, a low drone, a singing bowl. None of them are audio files. They are synthesised as they play, which keeps the app small and means there is no seam where a loop repeats. A 30-minute sleep timer fades the sound in over two seconds and out over 45.

00:12 - Asleep. The microphone stays on and the analysis runs as a foreground service, so the screen going dark does not stop it. Some phones stop recording apps to save power; if yours does, use "Allow background recording" in Settings. Keep the phone plugged in: a full night uses a lot of battery.

03:05 - Turning over. Body movement from the accelerometer, and the sound level at that moment, are the entire basis for estimating sleep depth. There is no heart rate or SpO2 reading, because Somnia is a sleep tracker for people who do not wear a watch to bed. Every 60 seconds it places one of four sleep stages (awake, light, deep or REM), smoothed over the surrounding two minutes.

06:45 - Wake alarm. It is set as a system alarm clock. On Android 14 and later you may need to allow "Alarms & reminders" for it to ring on time; without that permission it rings through a notification and can be late.

07:00 - Up. The sleep score runs from 0 to 100 and breaks down as duration 35, efficiency 25, continuity 20, depth 12 and quiet 8, measured against a 7.5-hour target.

No audio is kept
Somnia never writes sound to disk. What remains is numbers (the sound level trace, the spectrogram image, and the time and type of each event) and they are stored on the phone. No code in the app sends them anywhere (the Internet permission it lists comes from a Google Play library; if Android's own device backup is on, it may copy app data). The trade is that you cannot play your snores or sleep talk back. If playback is the point, this is the wrong app. All nights can be deleted at once from Settings; there is no export.

Free
A full night of detection, all four sound types, four-stage sleep, the sleep score and its breakdown, the wake alarm, eight of the 14 sleep sounds, and the sensitivity slider. History covers the last 3 days, and each night lists 3 events per sound type.

Pro adds
The full history, up to 40 events per sound type, the spectrogram (the whole night's sound as one image) and all 14 sleep sounds. Monthly, yearly, and a one-time purchase.

Please note
Somnia is not a medical device. Sleep stages are estimated from movement and sound, not measured, and the app cannot diagnose bruxism or any other condition. It does not detect sleep apnea. If you are concerned about your sleep or breathing, talk to a doctor. Interface in English and Japanese.

Recent changes:
The Back button now closes the morning summary, Pro and licenses screens instead of leaving the app.