OneTaskBy Tim King · Updated
Motion Detection Camera
Webcam Motion Detector That Beeps and Saves a Timestamped Photo on Movement
OneTask is free, with no sign-up, and built by one person.
If this tool saved you time, a coffee helps keep new ones coming.
How the Motion Detection Camera works
This motion detection camera turns your webcam into a simple motion sensor. Press Start camera, point it at a door, desk or window and leave it running. Moving areas glow red, the page can beep, and each event takes a time-stamped photo you can save. Video stays on your device.
How the motion detection camera works
Each frame is shrunk to a small grid and compared with the frame before it. Any cell whose brightness changes by more than the sensitivity threshold counts as moving. When the share of moving cells passes the trigger level, the page records an event, outlines the picture in red and takes a photo with the date and time written in the corner.
Getting the settings right
Sensitivity decides how big a brightness change counts, while the trigger percentage decides how much of the picture must change. A small trigger catches a cat crossing the far side of a room; a larger one ignores flickering screens, leaves blowing outside a window or the noise a cheap webcam adds in dim light. The gap between events stops one person walking past from filling your downloads with dozens of near-identical photos.
Good uses
Check whether someone came to your desk while you were away, see when a pet jumps on the sofa, watch a delivery spot, count birds at a feeder or time when a door opens. Choose "Save each one" to download every event photo automatically, or keep only the latest and save it when you return.
Limits
The tab must stay open and the computer awake. Most browsers slow down hidden tabs, so leave the window visible. Sudden lighting changes, such as a light switching on or clouds passing, can set it off.
FAQ
Is the motion detection camera recording or uploading video?
No. Frames are compared in your browser and then thrown away. Nothing is uploaded and nothing is recorded except the single photo taken at each event, which stays on the page or goes straight to your downloads folder if you choose to save each one.
Why does it keep triggering with nothing moving?
Webcams add grainy noise in low light and adjust their exposure constantly, which looks like movement. Lower the sensitivity, raise the trigger percentage, add more light to the scene or point the camera away from windows, screens and anything that flickers.
Can I use my phone as a motion sensor?
Yes. Open the page in a phone browser, allow the camera and prop the phone against something. Keep it plugged in with the screen awake, because phones pause camera access as soon as the screen locks or you switch to another app.
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