← Hunter Whyte
00 Overview WIP

Wearable jump tracking device for athletes

The goal: Detect jump height and frequency for progression tracking and stress monitoring in athletes.

Theory of operation: Continuously monitor for flight time and ground contact time events using a wearable 3-axis accelerometer, and upload the results to a mobile app over BLE.

Jump height, and other metrics such as RSI (reactive strength index) can be derived from flight time using basic projectile motion equations (with an added calibration factor).

Video overlay generated automatically using outputs from on-device processing.

Height, flight time and ground contact are burned into the clip by the mobile app after the session is synced.

01 Hardware Design

3D render of the jump tracker PCB
Board render — SoC module, accelerometer, NOR flash and PMIC on a single thin PCB.

Form Factor: The jump tracking device needs to be discreet and unobstructive for in-game use by ball sport athletes (basketball, volleyball etc.). The form factor of the device is a thin clip to be worn on the athlete's waistband (prototype dimensions: ~38mm x 13mm x 7.5mm).

Printed enclosure, battery and PCB, and the assembled clip held between two fingers
Left — printed enclosure, LiPo cell and populated board. Right — assembled form factor prototype.

02 Processing & Validation WIP

[WIP] — tooling built so far:

JumpValidator tool showing a video frame beside the accelerometer trace with event markers
JumpValidator — high frame rate video is scrubbed to the frame of takeoff and landing and marked by hand, then lined up against the accelerometer trace to produce labelled ground truth for each jump.
JumpInspector tool comparing baseline and candidate detection algorithms over a recorded session
JumpInspector — replays a recorded session through several candidate detection algorithms at once and diffs their event markers and jump counts against the labelled baseline.

03 Mobile App WIP

[WIP] — the app scans for nearby clips over BLE, records a live session, and can burn the resulting jump data into a video of the session.

Nearby devices screen listing two clips found over BLE
01 · Scan
Connecting screen with BLE progress ring
02 · Connect
App home screen with connected device, start session and make a clip
03 · Home
Live session screen with session stats, acceleration profile and jump log
04 · Live session
Sync screen scrubbing video to the takeoff frame
05 · Sync to takeoff
Rendering progress screen compositing the overlay
06 · Render

Session view shows best and average height and flight time, a per-jump takeoff / flight / landing acceleration profile, and the running jump log.