findphone

Find your own iPhone in a room using your Mac's Bluetooth signal strength.

Live simulation. Browsers can't measure Bluetooth signal strength, so this demo simulates the signal from a hidden phone. Everything else (median smoothing, closer/farther trend, the direction sweep, the speedometer and arrow) uses the same rules as the real macOS app.

The room (top-down)

Click or tap anywhere in the room to walk there. Keys: W / ↑ step, A / ← and D / → turn. The blue wedge shows which way you face.

🎉 Found it!

findphone

Walk a few steps

findphone needs a few seconds of movement to see a trend.

Click faster as I get closer

How the real app works

Measure: CoreBluetooth connects to your confirmed device (link only, never pairs) and reads its RSSI every 0.3 s.
Clean: readings outside -126…-1 dBm are rejected; the speedometer shows the median of the 7 newest.
Trend: the last 3 s vs the 3 s before. A change of 3 dB or more means closer or farther.
Direction: turn on the spot in four quarter-turns. Your body blocks some signal from behind you, so the strongest direction is usually the phone's. A 3 dB lead is "likely", 6 dB "strong".
Limits: RSSI shows proximity, not exact distance. Macs have no Ultra-Wideband chip, so direction is estimated. For a truly lost phone, use Apple's Find My.