Universal Bike Radar

pablo_maly

In-app purchases

About this app

Universal Bike Radar turns your phone into a display for a rear-facing bicycle radar. Cars approaching from behind appear on a road strip with their distance and closing speed, and you hear a warning before you see them in the mirror.

REQUIRES A COMPATIBLE RADAR
This app is a display, not a radar. You need a rear-facing bicycle radar that talks Bluetooth LE — W100 and compatible clones, Garmin Varia, Bryton Gardia, Magene, iGPSPORT and others using the same protocols. The hardware is not included.

WHAT YOU GET
• A road strip you can read at a glance: each car keeps its own colour, distance and closing speed, plus the seconds until it reaches you
• Sound and vibration warnings, louder and faster the closer a car gets
• A separate red alert for anything approaching fast, with the threshold you choose
• A convoy warning — because after the first car passes, the decision is different
• Works in the background with the screen off and the phone in your pocket, and tells you if the radar goes silent
• Optional red alert on your watch
• Easy on the battery: a ride ends by itself after 10 minutes without the radar
• Standby mode: the screen goes black on an empty road and wakes itself when the radar sees a car
• Orientation lock, so a phone in a handlebar mount stops flipping

ONE KNOB THAT MATTERS
Alert sensitivity runs from 1 (only what is truly urgent) to 5 (every car announced), and you can change it with one tap on the ride screen without opening settings. The levels were measured on hours of real radar recordings, not guessed: on the same city ride level 1 plays 2.1 warnings per minute and level 5 plays 16.

QUIET WHEN IT SHOULD BE
Warnings that carry no information are removed on purpose. Cars that are moving away do not beep. A car that has already passed goes silent instead of trailing five more beeps. With the W100, cars coming towards you in the opposite lane stay silent too. In dense traffic, where something is behind you all the time, the routine ticking stops — the red alerts and convoy warnings keep playing, because those tell you something you do not already know.

FREE, AND A COFFEE IF YOU LIKE IT
Detection, warnings, background operation, muting, vibration, ride recording and the paired radar are free and stay free. The free version runs on one alert preset, "Standard", deliberately the middle of the scale.
A single optional purchase — buy me a coffee — unlocks the other sensitivity presets, manual alert tuning, alert tones, appearance options including standby mode, and ride history. One payment, no subscription, no ads, ever.

SEND A RECORDING — THAT IS HOW THIS APP GETS BETTER
The alerts are tuned on recordings from real roads, so every new recording genuinely improves the app. The app records each ride on your phone: radar readings and the alerts it played, no GPS location. If it beeps too often or too rarely, send the recording: Settings → Advanced and help → Diagnostics → "Send to the developer". A ready email to [e-mail] opens with the recording attached; add two sentences about what happened.
Your radar is not on the list or does not work? On the search screen turn on "Show all BLE devices", pick your radar and ride for a while so that a few cars pass you. Then send the recording the same way and name the radar model. From that recording I can check whether support can be added — that is how W100 support was built.

PRIVACY
No accounts, no ads, no analytics, no servers. Nothing leaves your phone unless you press "Send" on a recording yourself. The app never reads your position. A location permission is declared only for Android 11 and older, where the system required it to scan for Bluetooth devices — Google Play lists it regardless of your phone's version.

SAFETY
A radar is an aid, not a substitute for looking behind you and riding predictably. Set the app up before you ride, mount the phone properly, and keep your eyes on the road.

What’s new

Cars in the opposite lane no longer trigger alerts (W100 radar). Time to reach under the distance ("in 4 s"). The red screen matches the red alert and no longer flickers; vehicles that have passed are dimmed. A warning when the radar goes silent while connected. Lower battery use: a ride ends by itself after 10 min without the radar, plus an "End ride" button. Optional red alert on your watch. Labels next to cars are easier to read.