Ripple: WiFi Motion Alert

Ripple tells you when someone walks between your phone and your WiFi router. It needs no camera, no sensor and no extra hardware: a body in the path weakens the WiFi signal, and Ripple watches for that drop.

HOW IT WORKS
• Place the phone so the line to your router crosses the spot you want to watch, like a hallway or a doorway.
• Tap Start watching. Ripple learns the empty room in about 20 seconds.
• When someone crosses, Ripple vibrates, plays a sound and shows the alert, usually within a few seconds.
• Someone who stops in the path keeps the alert on.

ALERTS WHEREVER YOU ARE ON THE PHONE
• In Ripple: the screen shows "Someone's crossing".
• In another app: a card slides up over it.
• Phone locked: the alert lights the screen over the lock screen, like an alarm clock.
• On Android 16 and later, a status bar chip shows "Clear" or "Alert" at a glance.

WAYS TO USE IT
• Know when someone comes up behind you while you work.
• Watch a hallway, a doorway or a room while you're elsewhere in the house.
• Check whether anyone went past while you were out of the room: Ripple keeps a list of crossings with their times.

MADE TO BE TRUSTED
• Pauses on its own if the phone is picked up or moved, then learns the room again.
• Adjustable sensitivity, from big clear crossings only to very touchy.
• A test alert lets you try every alert before you rely on it.

PRIVATE BY DESIGN
• No account, no ads, no analytics.
• No location access, no camera, no microphone.
• Nothing leaves your phone. Ripple only talks to your own router.

GOOD TO KNOW
• Ripple watches one line, from the phone to the router, not the whole house.
• Keep the phone plugged in with the screen on (dimmed). Android refreshes the WiFi signal only while the screen is on, so Ripple catches far fewer crossings with the screen off.
• Works best in the same room as the router. Walls weaken the signal.
• Ripple is a helpful alert, not a certified security or alarm system.