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Bike Radar

Overlay and audio alerts for BLE bike radars. Offline, no account, no cloud.
New in version 1.2.0
Home Assistant MQTT topics move from varia/ to bikeradar/, so anything you trigger on a raw topic needs repointing by hand. Your entity ids keep the naming they have, but every entity is registered afresh and some come back with a _2 on the end; anything pointing at an affected id stops working until you delete the stale entity and rename the _2 back. Check your battery sensors, the close-pass event, and, if you have the camera, the front light mode. The rebuilt entities start with no history. I
Bike Radar shows and sounds what your rear bike radar sees, on top of whatever app you are already running.

A thin strip down the edge of the screen shows each approaching vehicle's distance, closing speed and lateral position over your map or navigation app. Tiered beeps rise as the closest vehicle gets nearer, and a distinct urgent tone fires when an impact looks imminent - including while you are rolling slowly toward a junction with a fast vehicle behind. A clear chime sounds when the radar no longer sees vehicles behind.

Everything runs on your phone: no account, no cloud, no analytics. The optional Home Assistant integration publishes ride stats to your own server and nowhere else.

Features:

- Live overlay with per-vehicle distance, closing speed and lateral position
- Tiered proximity beeps, urgent imminent-impact tone, all-clear chime
- Post-ride summary notification: overtakes, close passes, distance, tightest pass
- Front camera/light auto mode by local sunset (one coarse location read per ride)
- Bosch Smart System eBike telemetry, strictly read-only
- Walk-away and forgot-to-lock reminders
- Optional Home Assistant publishing: batteries, close passes, ride summaries
- Optional on-device capture log for diagnostics, off by default and never uploaded
- English and Spanish

Requires a rear radar that speaks the V2 BLE protocol (pair it once in system Settings) and Android 12 or newer. The radar, camera and eBike integrations degrade gracefully: each works without the others.

Bike Radar is a riding aid, not a safety guarantee. It supplements your own attention and mirrors - it never replaces them.

This is an independent open-source project (GPL-3.0-or-later), not affiliated with or endorsed by any radar or eBike manufacturer.

Versions

Although APK downloads are available below to give you the choice, you should be aware that by installing that way you will not receive update notifications and it's a less secure way to download. We recommend that you install the F-Droid client and use that.

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  • Version 1.2.0 (23) suggested Added on Aug 21, 2026

    arm64-v8a armeabi-v7a x86 x86_64

    This version requires Android 12 or newer.

    It is built and signed by the original developer, and guaranteed to correspond to this source tarball.

    Permissions
    • access approximate location only in the foreground
      This app can get your approximate location from location services while the app is in use. Location services for your device must be turned on for the app to get location.
    • connect to paired Bluetooth devices
      Allows the app to connect to paired Bluetooth devices
    • discover and pair nearby Bluetooth devices
      Allows the app to discover and pair nearby Bluetooth devices
    • run foreground service
      Allows the app to make use of foreground services.
    • run foreground service with the type "connectedDevice"
      Allows the app to make use of foreground services with the type "connectedDevice"
    • run foreground service with the type "mediaProjection"
      Allows the app to make use of foreground services with the type "mediaProjection"
    • android.permission.FOREGROUND_SERVICE_SHORT_SERVICE
    • have full network access
      Allows the app to create network sockets and use custom network protocols. The browser and other applications provide means to send data to the internet, so this permission is not required to send data to the internet.
    • show notifications
      Allows the app to show notifications
    • run at startup
      Allows the app to have itself started as soon as the system has finished booting. This can make it take longer to start the phone and allow the app to slow down the overall phone by always running.
    • This app can appear on top of other apps
      This app can appear on top of other apps or other parts of the screen. This may interfere with normal app usage and change the way that other apps appear.
    • control vibration
      Allows the app to control the vibrator.
    • prevent phone from sleeping
      Allows the app to prevent the phone from going to sleep.
    • es.jjrh.bikeradar.DYNAMIC_RECEIVER_NOT_EXPORTED_PERMISSION

    Download APK 7.6 MiB PGP Signature | Build Log