Find That Bleeping Alarm

Every smoke and carbon monoxide alarm chirps when its battery runs low: one short beep every 30 to 60 seconds, usually at night, and almost impossible to place by ear because 3 kHz bounces off every wall. Find That Bleeping Alarm listens with your phone's microphone, catches each chirp, and scores how loud it was. Move between chirps and the app tells you whether you are getting warmer or colder. Most people find the alarm within four or five beeps. HUNT TOGETHER Open the app on every phone, iPad or Mac in the house, tell each one which room it is in, and tap Listen. When the next chirp comes, every device scores it, and the room that heard it loudest is shown first. No accounts, no setup: devices find each other over your own Wi-Fi and Bluetooth. BUILT FOR THE JOB • Hears the 2.6–4.4 kHz chirp of smoke and CO alarms, and ignores typing, cutlery and dripping taps • Learns the chirp…