SWINGLAB

YOUR MOTION, UNDER THE MICROSCOPE

Find the shape
of your swing.

Feel it in your hand. See it in the data.

A POCKET-SIZED INSTRUMENT

Acceleration. Rotation. Rhythm.
Every sample has a story.

01 / CAPTUREiPhone motion sensors

A little room. A few good swings.

Hold securely. Stay clear of people and objects. Start with gentle swings.

Hold still to calibrate → swing → pause between swings
02 / UNDERSTANDSAMPLE DATA

A study in six swings

Repeatability—Variation in acceleration peaks ↓

The acceleration signature

Six gestures. One continuous recording.

Resultant
m/s²
0.000 s · 0.0 m/s²
Drag across the trace to inspect every sample.

Swing by swing

Select a row to look closer. Overlay to compare shapes.

SwingShapePeak m/s²Speed m/sActive s
Under the surface Sample values, units & measurement limits

Charts retain every received sample. Acceleration is in the phone’s coordinate frame; the resultant combines all three axes. The browser may filter or limit sensor values before delivering them.

Estimated speed is the phone’s translational speed, not racket-head, shuttle, or ball speed. It uses orientation-aware integration between stationary endpoints. There is no universal accuracy guarantee. Missing orientation, long gaps, or excessive drift suppress the estimate.

03 / YOUR NOTEBOOK

Practice, kept.

Saved on this device. Yours to revisit and export.

Browser storage can be cleared by iOS or by you. Export recordings you want to keep.

FIELD GUIDE

Your phone.
A motion instrument.

  1. Make a little space.

    Use a secure grip or wrist strap, with nobody in your swing path. Begin slowly. Don’t attach the phone to a racket.

  2. Hold still, then move.

    Allow motion access in Safari. Hold still for calibration. Make a few controlled swings, resting for about a second between each. A session lasts up to 20 seconds.

  3. Look for a repeatable signature.

    Inspect the trace, select individual swings, then overlay them. Compare the same grip, sport, and stroke across sessions.

The sport and stroke labels organize your notebook. They don’t change the measurements or imply a technique score.
MEASUREMENT NOTES

Precision in the data.
Honesty in the claims.

Acceleration · m/s²
The magnitude of the browser’s gravity-removed x, y, z acceleration after a stationary bias calibration. 1 g = 9.80665 m/s². Peaks use all received samples.
Rotation · °/s
The magnitude of the three gyroscope rates. This describes how quickly the phone rotates, regardless of axis.
Estimated phone speed · m/s
Acceleration is rotated into a shared reference frame using device orientation and integrated with actual time intervals. We impose zero speed at stationary endpoints and remove linear velocity drift. Estimates are withheld for missing/stale orientation, gaps over 100 ms, missing rest, or large endpoint drift. This is experimental, not a radar measurement.
Repeatability · % CV
Standard deviation divided by mean of the swing acceleration peaks. Lower means more similar peaks in this session. It isn’t a measure of sporting skill or a complete comparison of swing shapes.
Swing detection & duration
A swing starts above 3 m/s² or 100°/s and ends after a quiet interval. Active duration runs from first to last threshold crossing. Events shorter than 120 ms stay in the trace but are not counted as swings. Slow gestures may not register; an uninterrupted sequence may be one swing.
What this cannot measure
Ball speed, racket-head speed, impact force, spin, precise spatial trajectory, and technique quality cannot be inferred reliably from a handheld phone. Browser sampling may miss a very brief peak.

Raw exports include all captured samples and timestamps. JSON also includes calibration and session metadata. No recordings are uploaded.
TAKE YOUR DATA

Every sample.
No lock-in.

Export the selected session at its original browser resolution.
YOUR POCKET LAB

Ready when you are.

On iPhone, open this page in Safari. Tap Share, then Add to Home Screen and Add.

Open the installed app once while online so its files can be saved. Your recordings stay in this browser or installed app; Safari and the installed app may use separate storage.

Offline availability is shown in the footer.
YOUR NOTEBOOK

Delete this recording?

This removes the session from this device. Export it first if you want a copy.