Bring your own everything.

Your tablet, or your phone

What you need

Any tablet or phone running Android 7.0 or newer, with GPS and a 64-bit processor. Around 200 MB free covers the app and its offline road data.

Good to know

• Check for GPS before you buy. Plenty of Wi-Fi-only tablets don't have it.
• Google Play Services aren't needed. On a tablet without Google apps, install the APK instead.
• 8 inches or bigger makes split-screen comfortable, but the layout fits itself to whatever it gets.

If it has an OBD-II port, it's in

What you need

An OBD-II port, which every petrol car sold in the UK and EU since 2001 and every diesel since 2004 has. It is usually under the dashboard, near the steering wheel.

Good to know

• Cars don't all report the same readings. BTYSHU checks what yours supports and only shows what's really there.
• No adapter at all? Speed, limits, cameras and journeys all work on GPS.

No locked-in dongle

What you need

An ELM327-compatible adapter that uses Bluetooth LE. Plenty of brands make them, and BTYSHU talks to it directly, so it doesn't need an app or account of its own.

Good to know

• Bluetooth LE is the part that matters. Classic Bluetooth and Wi-Fi adapters won't connect.
• Some adapters stay powered with the ignition off. If the car will sit unused for weeks, unplug it.

Fit it however suits your car

What you need

Anything that holds the screen steady, within easy reach, and clear of your view of the road.

Good to know

• Keep it well away from airbag panels. Anything fixed there gets thrown if the airbag goes off.
• A factory sat nav cradle, a vent clip or a suction mount all work. It's worth a little more for one that doesn't rattle.

Keep it topped up

What you need

A USB supply with enough power to charge while the screen, GPS and Bluetooth are all running.

Good to know

• Weak built-in USB ports can let the battery drain slowly on a long drive. A decent 12V adapter fixes that.
• Route the cable so it can't catch on the gear lever or the steering wheel.

Keep the sat nav you like

What you need

Any nav app that runs in Android split-screen, including Waze, Google Maps and Sygic.

Good to know

• Open BTYSHU, open your nav app, then use the recent apps screen to put them side by side or top and bottom.
• BTYSHU doesn't draw a map of its own, so the two never compete for the same job.