Is someone snooping on your phone?
Find out who touched your phone when you weren’t looking. Curious friends, partners, family members or anyone else — you deserve to know when someone handles your phone without permission. Arm ScreenSentry with a decoy screenshot. If someone touches that screen, ScreenSentry takes a front-camera photo and locks your phone.
Signed release APK, tested by the developer. No account, subscription or payment required. Installation and setup guide · SHA-256 checksum
A simple way to spot unwanted phone snooping
When you leave your phone nearby, ScreenSentry can help you see who touched the decoy while it was armed. It does not read private messages or watch other apps.
Once armed, a touch on the decoy triggers one front-camera photo. Check the picture later to see who was in front of the camera.
After the photo is captured, ScreenSentry locks your phone. Simply pressing the power button does not trigger a photo.
Images go into Pictures/ScreenSentry. No ScreenSentry cloud service, accounts, or in-app advertising.
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Could someone be peeking at your private information?
You might be concerned about a friend opening your phone, a partner looking through your messages, or a family member browsing your photos without asking. ScreenSentry provides a clue about who touched the activated decoy screen — without making accusations or trying to guess anyone's intentions.
How ScreenSentry works
Pick a screenshot from your own phone to display as a decoy.
Leave the decoy visible. Only a touch inside this armed screen triggers the camera.
When touched, it captures a photo, saves it on your phone, then locks the device.
Download and install in three steps
On your Android phone, download the signed ScreenSentry-Android-v1.2.1.apk from this page.
Open the downloaded APK using Files or your browser. If Android asks, allow this trusted source to install the app, then turn that permission off afterward.
Choose a decoy screenshot, approve camera and device-lock permissions, and tap Arm. If someone touches the decoy, one front-camera photo is saved and the screen locks.
This is a direct Android APK download, not a Google Play Store app. Only install apps you trust; Android may show its usual security prompts. For details, see the full installation guide. The physical power button and simply picking up the phone do not trigger a photo.
Important to know
A photo can show who was in front of the camera when the armed decoy was touched; it cannot prove someone was snooping or tell you whether any private information was accessed. ScreenSentry does not monitor Android's real home or lock screen, run a background camera, or identify people by name. Android displays the normal camera privacy indicator. Use ScreenSentry only on a device you own or are authorized to protect and follow local privacy rules.