Developer Builds Privacy-First Android App to Auto-Silence Phones Without Cloud

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A developer created Muffle, an Android app that automatically adjusts phone sound profiles based on scheduled routines and location, after being inspired by a disruptive ringtone during a mosque sermon. The app was deliberately built with a zero-cloud architecture, meaning all data and logic remain entirely on the user's device. It uses Android's AlarmManager, ForegroundService, and GeofencingClient alongside a local Room database to manage sound rules without any server dependency. Prayer time calculations are handled on-device via the Adhan library, avoiding the need for cloud functions or external APIs. A key technical hurdle was Android's Doze mode, which delayed alarm triggers and required additional engineering to ensure timely sound profile transitions.

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