Danny Chait
All work

Blue Tees Golf · Product Manager · 2025–2026

Launch App

Rainmaker's companion app, defined from a blank page. Owned the first-version requirements including the Bluetooth data protocol between device and app, then shipped simulator integrations, session history and notifications, and now the subscription and AI roadmap.

  • Mobile
  • iOS & Android
  • Protocol Design
  • Monetization
0 → 1
Scoped the first version from scratch
2
Simulator platforms integrated
iOS + Android
Phone and tablet

The problem

Competing devices at this price shipped with minimal companion software or none. Golfers got a number on a screen and no way to see whether they were improving.

What I did

  • Defined the first version from a blank page. Scope, iOS and Android across phone and tablet, and the practice, swing speed and target distance structure that shaped the rest of the app.
  • Wrote the Bluetooth data contract between device and app. Shot metrics, club data, battery and firmware state travel one way; player profile, selected club, session mode and firmware trigger travel the other.
  • Specified both directions before either side was built, so the hardware and app teams could work in parallel against something fixed instead of negotiating the interface as they went.
  • Kept shipping after launch: GSPro and E6 simulator integration, session history with calendar and shot-by-shot review, and push notifications for achievements, summaries and firmware.

Results

  • Zero to a shipped first version, then three further feature cycles delivered.
  • Simulator integration extends the same hardware from the driving range into indoor play, with no hardware change.
  • The release, with Rainmaker, drove the highest revenue month in company history.

Now

Leading subscription monetization, AI post-session reports, an AI consistency score, and French-Canadian localisation to unblock a specific sales deal.

Artifacts

Four-part diagram. The device: Rainmaker, a Doppler radar unit that works standalone with its own screen, running practice, swing speed and target distance modes with no app connected. The data contract over Bluetooth Low Energy, specified in both directions: device to app sends ball speed, launch angle and direction, apex, carry, total distance, hang time, descent angle, back spin, side spin, spin axis, club speed, club path, attack angle and smash factor, plus battery, firmware version and connection state; app to device sends the player profile and preferences, the selected club so a shot arrives already attributed, the session mode, and the firmware update trigger. The app on iOS and Android, phone and tablet: session history with calendar review, dispersion maps, My Bag club data synced to the device, and push notifications. Out again: the GSPro and E6 simulator platforms, fed from the same app connection.
The data contract. Both directions were specified before either side was built, which is what let hardware and app teams work in parallel.