Trajectory (trajectory.meckman.org) · Effective October 11, 2026
Trajectory is a public web app for robotics students and mentors. It measures a ball launcher's exit speed and launch angle from a video the user loads, and builds a distance to setpoint table for robot code. It runs entirely in the web browser.
| Data | Why | How it is obtained |
|---|---|---|
| Video files the user chooses | To find the ball in each frame | Picked or dropped in by the user; decoded in the browser and never uploaded |
| Shot measurements and the labels the user types (setpoint, hood, notes) | To build consistency stats and the shot table | Entered by the user |
| CSV files from other tools | To compare results on the Compare page | Picked by the user; read in the browser |
| Preferences (mentor mode, ball color, current session) | To remember settings between visits | Saved by the app in the browser |
On the user's own device only. Shot data is kept in the browser's IndexedDB and preferences in localStorage. Video frames are held in memory while the page is open and discarded when it closes. Nothing is sent to a server operated by the developer.
None. The site's files are served by Cloudflare, which, like any web host, receives standard request information (such as IP address and browser type) when the page loads. The app sends no videos, measurements or personal information to Cloudflare or anyone else. There are no accounts, analytics, advertising or cookies. A session is shared only if the user exports a session file and sends it themselves.
Data stays in the browser until the user deletes shots or sessions in the app, or clears the site's data in browser settings.
Trajectory is used by students on robotics teams. It collects nothing personally identifying from them; the only text it stores is what the user types into shot notes, and that stays on the device.
If this policy changes, the updated version will be posted here with a new effective date.
Andrew Meckley · andrew.meckley1981@gmail.com