// SPDX-License-Identifier: MIT

RadAlert

A standalone Apple Watch app that connects directly to a Garmin Varia radar and delivers haptic alerts when vehicles approach from behind — no iPhone app required.

Features

• Connects to Garmin Varia radar via Bluetooth directly from the watch
• Haptic alerts (4-pulse pattern) when new vehicles are detected
• Elapsed time and cumulative vehicle count displayed during rides
• Saves cycling workouts to Apple Health (optional — choose at end of ride)
• First-launch onboarding flow with safety acknowledgement and permission setup
• Fully standalone — works without a companion iPhone app running

Requirements

• Apple Watch (watchOS 10.5+)
• Garmin Varia radar device
• iPhone paired to the watch (required for initial Xcode installation; not required at runtime)
• Xcode 15.4+ for building

Getting Started

1. Open VariAlert/RadAlert.xcodeproj in Xcode
2. Select the RadAlert Watch App target
3. Under Signing & Capabilities, set your Development Team
4. Connect your iPhone via USB and select your Apple Watch as the run destination
5. Hit ⌘R to build and install

Usage

1. Open the app on your Apple Watch and acknowledge the safety notice
2. Tap Start Ride — this begins a HealthKit workout session and starts scanning for your Garmin Varia
3. Once the radar connects, the status shows Radar Connected
4. Ride — the watch will vibrate when vehicles approach from behind
5. Long-press Stop to end the session; choose End and Save to record the ride to Apple Health, or End and Discard to discard it

Notes

• Apps signed with a free (personal) Apple Developer account expire after 7 days. A paid Apple Developer Program membership ($99/yr) is required for longer-lived installs.
• The app requires Bluetooth and HealthKit permissions on first launch.
• Privacy policy: https://carlineng.github.io/RadAlert/privacy.html

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Safety Disclaimer

RadAlert is a supplemental awareness tool and is not a certified safety device. It cannot guarantee detection of all vehicles. Always follow traffic laws, remain alert, and rely on your own judgement while riding. Use at your own risk.

Disclaimer

This software is provided "AS IS", without warranty of any kind, express or implied, including but not limited to the warranties of merchantability, fitness for a particular purpose, and noninfringement. In no event shall the authors or copyright holders be liable for any claim, damages, or other liability, whether in an action of contract, tort, or otherwise, arising from, out of, or in connection with the software or the use or other dealings in the software.

Maintenance & Support

No SLA. Issues and PRs may be ignored or closed without response. There is no guarantee of updates or compatibility.

Security

If you find a vulnerability, you may report it via Issues or email (optional). We do not commit to remediation timelines or fixes. Use at your own risk.

Contribution

By submitting a contribution, you agree it is your own work and you grant the project a perpetual, worldwide, non-exclusive, royalty-free license to use it. Contributions are provided "AS IS", without warranties or guarantees of inclusion.