Backyard Lap Timer
Choose who is driving, which car, and where you are racing.
Pilots
Tap a pilot to use them in your next session.
Add pilot
Cars
Choose a car or review its setup.
Add car
Tracks
Choose the track for your next session.
Add track
Results
Completed sessions saved on this device.
Race
Open the camera, draw the finish line, and calibrate before starting.
1 Camera & finish line
Camera options & zoom details
Open the camera to see which zoom controls your browser supports.
Draw a line, then calibrate with the track empty.
2 Detection
Open the camera and draw a finish line to begin.
3 Practice session
Target: 10 laps ·
Choose a track to set the session condition.
Ghost reference
References show best lap and valid laps total. Same track, layout, surface, condition and direction. Invalid laps make a session ineligible as a Ghost reference. Gap and voice update at each completed lap; negative means ahead.
Session: Idle
Live timing
Projection uses completed-lap average after 2 laps, excluding pauses. Ghost gap updates at the line.
Waiting for detection to start.
Lap history
| Lap | Time | Delta to best |
|---|
Session summary
Detection diagnostics
The orange line marks the finish. A and B show the detector zones. Directions refer to movement on the camera image. Increase zone size under Settings for fast passes.
Zone motion: A — · center — · B —
Camera setting: — FPS · requested: 60 FPS
Screen Wake Lock is inactive.
Last candidate: —
Experimental camera timing: A/center/B activity estimates a crossing direction but does not identify a specific car. People, shadows, camera shake, or other movement can still trigger a crossing. Lap times use the detector's center-line timestamp. Ending a session discards the unfinished final lap, and camera processing stays on this device.
Community
Community is a feature planned for future development. Stay tuned for updates.
Sign in or create an account
Keep using the timer without an account. Signing in creates your Backyard Lap Timer account; your Garage and lap history remain on this device for now and are not synced to the cloud.
Checking sign-in availability…
Settings
Saved automatically on this device. Open a group when you need to change it. Draw the line and calibrate on Race after positioning the phone.
Two-device setup (optional)
This device only is the default. For remote operation, open this app on two devices connected to the same Wi-Fi. Pair with two animated QR sequences; keep each camera pointed at the other screen until scanning completes. No account or signaling server is needed. Timing and saved results stay on the Sensor. Pair before mounting the Sensor phone.
1. Create an offer and have the Viewer scan it.
2. Scan the answer displayed on the Viewer.
1. Scan the Sensor offer QR, then show the answer QR to the Sensor.
2. Keep this answer QR visible until the Sensor scans it.
Single-device mode.
Finish line settings
Zone size controls the area watched around the line. Direction refers to movement in the camera image, regardless of how the line was drawn.
Detection sensitivity
Calibration sets the threshold for the current lighting. Change this manually only if detection needs tuning.
Lap timing
Crossings sooner than the minimum lap time are detected but ignored by the lap timer. This protects against duplicate triggers.
Sound alerts
Install the app
Add Backyard Lap Timer to your home screen for quick access. Open this page in the browser listed below first.
iPhone / iPad · Safari
- Open this page in Safari.
- Tap Share (the square with an up arrow).
- Tap Add to Home Screen (you may need to scroll).
- Tap Add to confirm.
Android · Chrome
- Open this page in Chrome.
- Tap the three-dot menu ⋮.
- Tap Install app or Add to Home screen.
- Confirm Install or Add.
Computer · Chrome / Edge
- Click the install icon in the address bar, if shown.
- Choose Install.
- Alternatively, open the browser menu and select Install Backyard Lap Timer.
If an install option does not appear, use the latest version of a supported browser and check its menu. Installing adds an app shortcut; your sessions remain stored on this device.
Camera choice, zoom, zone size, direction, sensitivity, minimum lap, alerts, and session length are remembered here. A different phone keeps its own settings. Clearing browser site data removes them.
Viewer / Controller
Waiting for Sensor…
Drag on the camera preview to set the finish line. The Sensor applies the line and all controls.
Consistency: —