Calculate approximate speed from distance and time with your phone camera.
Motion Radar – Rough Speed Estimates From Distance and Time
Motion Radar is a simple helper that gives you a rough estimate of how fast someone walked, ran or cycled past you. It does not use radar, GPS or any special sensor. It only uses your phone camera and the distance that you enter yourself. Results are estimates, not measurements, and can differ from the real speed.
How it works
1. Stand still beside a path, about 2 to 5 metres from where people pass.
2. Enter that distance in Settings. You need to know or estimate this distance yourself.
3. Tap DETECT and hold the phone steady, pointed across the path.
4. When someone crosses the picture from one side to the other, the app notices the movement in the camera image and shows an estimated speed.
How the estimate is made
The app compares camera frames to see how far the moving shape shifts across the screen and how long that takes. Together with the distance you entered, it calculates an approximate speed (distance divided by time). If the distance you enter is wrong, the result will also be wrong. Light, background movement, camera shake and the angle of the person passing also change the result.
Distance suggestion
When movement starts, the app sends one camera snapshot to an online image service. The service guesses what is passing, for example a person or a bicycle, and the app suggests a distance based on its typical size. This is only a rough guess, and you can always change the distance in Settings.
What you get
- Estimated top, lowest and average speed for each pass
- A history of your passes with a simple chart
- Bookmarks for the passes you want to keep
- km/h or mph, sound and vibration options, front or back camera
Good for
- Getting a rough idea of your own walking or jogging pace
- Comparing passes with friends out of curiosity
Important
- All results are approximate estimates.
- Motion Radar is not a radar device, not a speed camera and not a certified measuring tool.
- Do not use it for traffic enforcement, legal evidence, sports results or any safety decision.