DIY Golf Launch Monitor using the OPS243-A Doppler Radar.

OpenFlight is an open-source golf launch monitor that uses Doppler radar to measure ball speed, club speed, launch angle, spin rate, and carry distance.

• Ball Speed: 30-220 mph range with ±0.5% accuracy (OPS243-A)
• Club Speed: Detected from pre-impact readings (OPS243-A)
• Smash Factor: Ball speed / club speed ratio
• Launch Angle: Vertical launch measured by K-LD7 angle radar
• Club Path: Horizontal aim direction measured by second K-LD7
• Spin Rate: Via rolling buffer I/Q analysis (~50-60% detection rate)
• Carry Distance: Computed from ball speed, launch angle, and spin

The K-LD7 angle radars are optional. Without them you still get ball speed, club speed, smash factor, spin rate, and estimated carry. See the full parts list for details and links.

See the Parts List for everything you need with purchase links.

Follow the Sound Trigger Wiring Guide to connect the SEN-14262 to the OPS243-A. The K-LD7 modules connect via USB — no wiring needed.

Follow the Raspberry Pi Setup Guide for OS installation, software setup, radar configuration, and auto-start.

# Default: rolling buffer mode with sound trigger
scripts/start-kiosk.sh

# With K-LD7 angle radar
scripts/start-kiosk.sh --kld7 --kld7-angle-offset 13

# Development mode (no hardware)
scripts/start-kiosk.sh --mock

Then open http://localhost:8080 or use the touchscreen.

┌─────────────┐  USB/Serial  ┌─────────────┐  Callback   ┌─────────────┐  WebSocket  ┌─────────────┐
│  OPS243-A   │ ───────────▶ │   Launch    │ ──────────▶ │   Flask     │ ──────────▶ │   React     │
│   Radar     │  Speed data  │   Monitor   │  on_shot()  │   Server    │   "shot"    │     UI      │
└─────────────┘              └─────────────┘             └─────────────┘             └─────────────┘
                                                               ▲
┌─────────────┐  USB/Serial                                    │
│ K-LD7 (×2)  │ ──────────────────── angle data ──────────────┘
│ Angle Radar │
└─────────────┘

1. Sound trigger fires — SEN-14262 detects club impact, triggers OPS243-A HOST_INT
2. OPS243-A dumps buffer — Rolling buffer I/Q data is captured and analyzed for ball speed, club speed, and spin
3. K-LD7 correlates — The server uses the OPS243-A impact timestamp to find the matching ball burst in the K-LD7 ring buffer, extracting launch angle and club path
4. Carry computed — Ball speed + spin + launch angle → carry distance
5. UI updates — Shot data emitted via WebSocket to the React frontend

The OPS243-A transmits a 24 GHz signal. When it bounces off a moving object (the golf ball), the frequency shifts proportionally to the object's speed — this is the Doppler effect. At 24.125 GHz, each 1 mph of speed creates a ~71.7 Hz Doppler shift.

Place the radar 3-5 feet behind the tee, pointing at the hitting area:

                Ball Flight Direction
                ======================>

[Tee]  ←--- 3-5 ft ---→  [OPS243-A]  [K-LD7 vertical]  [K-LD7 horizontal]

The K-LD7 modules are positioned near the OPS243-A, one mounted vertically (launch angle) and one horizontally (club path / aim direction).

from openflight import LaunchMonitor

with LaunchMonitor() as monitor:
    print("Swing when ready...")
    shot = monitor.wait_for_shot(timeout=60)

    if shot:
        print(f"Ball Speed: {shot.ball_speed_mph:.1f} mph")
        print(f"Est. Carry: {shot.estimated_carry_yards:.0f} yards")

• Cosine error: If ball doesn't travel directly toward/away from radar, measured speed will be slightly lower than actual
• Spin detection: ~50-60% reliable — depends on signal quality and trigger timing
• K-LD7 speed aliasing: The K-LD7 max speed is 62 mph, so it's used only for angle/distance, not speed

Reflective markings (aluminum stickers, painted dots) noticeably improve K-LD7 launch-angle extraction — the stronger return gives multi-frame tracking, higher SNR, and more confident angles. However, a specular patch produces a pulsed, non-sinusoidal amplitude modulation that the spin detector can't interpret as seam modulation, so measured spin degrades (typically locks to the top of the valid frequency band with low confidence). Low-confidence spin automatically falls back to club-typical values in the ballistics model, so the net effect of marking a ball is better angles with no worse carry estimates. A thin painted stripe (rather than a patch) is a reasonable middle ground if you want both — it rotates through the beam more like a seam.

openflight/
├── src/openflight/
│   ├── ops243.py              # OPS243-A radar driver
│   ├── launch_monitor.py      # Shot detection & club/ball separation
│   ├── server.py              # Flask server, K-LD7 correlation, carry
│   ├── session_logger.py      # JSONL session logging
│   ├── kld7/                  # K-LD7 angle radar
│   │   ├── tracker.py         # Ring buffer, ball/club detection
│   │   └── types.py           # Data types
│   └── rolling_buffer/        # Spin rate detection
│       ├── monitor.py         # Rolling buffer monitor
│       ├── processor.py       # I/Q processing for spin
│       ├── trigger.py         # Trigger strategies
│       └── types.py           # Data types
├── ui/                        # React frontend
├── scripts/                   # Utility & setup scripts
├── docs/                      # Documentation
└── pyproject.toml

Contributions welcome! See CONTRIBUTING.md for guidelines.

Areas of interest:

• Better spin detection: Increase reliability beyond 50-60%
• K-LD7 signal processing: Improve ball detection from sparse radar frames
• Mobile app: Bluetooth connection to phone

uv run pytest tests/ -v

• Parts List — What to buy
• Sound Trigger Wiring — How to wire the sound trigger
• Raspberry Pi Setup — Full setup guide
• Rolling Buffer & Spin Detection — Spin measurement details
• K-LD7 Ball Detection Theory — How angle detection works
• K-LD7 Session Review — Offline review workflow for session JSONL files
• Observability & Log Shipping — Ship logs to Grafana Cloud
• Contributing Guide — How to contribute
• Changelog — Version history

GNU Affero General Public License v3.0 or later (AGPL-3.0-or-later) - see LICENSE file.

• OmniPreSense for the OPS243-A radar and documentation
• The golf hacker community for inspiration