Android Auto tablet setup turns spare Android into car display

You need three things: a spare tablet or retired phone to act as the screen, a USB cable that carries data rather than just power, and a main Android phone on Android 11 or later. Android Auto is already part of compatible phones, so the only thing you install is a receiver app on the tablet. That app pretends to be a car’s screen.

The best-known option is Open Headunit, which used to be called Headunit Revived. It costs $3.99 on Google Play and works on receiving devices running Android 5.0 or newer. Some guides written under the old name list an even lower floor of Android 4.1. The project is open source, so you can also install it free from its GitHub page if you are comfortable sideloading an app file. There’s also a version in the Amazon Appstore for Fire tablets at $4.70.

A second paid choice, Headunit Reloaded, costs $4.99. Both apps do the same basic job.

One catch with older tablets: not every one handles a phone-to-tablet USB connection well. You may need an OTG adapter (a small plug that lets a tablet act as the host for another USB device), and some very old hardware simply won’t cooperate.

Wired is the simplest route and usually the most dependable. When you first open the receiver app, it asks for location and microphone permissions, shows a safety notice and runs a short setup wizard where you choose the screen size and orientation. Pick the sideways orientation that matches a car display; the developer warns that upright portrait mode can cause trouble with Google Maps.

Then:

1. Plug the phone into the tablet with your data cable, adding the OTG adapter if the tablet needs one.
2. On the phone, open the USB notification, let this phone control the connection, and choose the Android Auto or file transfer option if asked.
3. On the tablet, open the receiver app, tap USB, allow it to use the connected phone and pick your phone from the list.
4. Accept the remaining prompts on the phone, and Android Auto should load on the tablet.

If the tablet doesn’t see your phone, try a different cable first. Many cables that came with cheap chargers only carry power.

Inside the app’s settings you can adjust the interface scale, switch on right-hand drive, set when dark mode kicks in, change the resolution, or have the app launch and connect automatically.

A wireless link is possible but takes more fiddling. The developer of the app recommends Wi-Fi Direct, which links the two devices straight to each other without a router or hotspot. You switch the tablet app to its wireless helper mode with Wi-Fi Direct selected, note the device name it shows, then install a companion app called Wi-Fi Helper on your phone and enter that name. If the two still don’t find each other, pairing them by hand in each device’s Wi-Fi settings usually sorts it out.

The trade-off with a cable is simple: USB fills the tablet’s charging port. On a tablet whose battery is already worn out, that matters, and wireless keeps the port free.

There’s also a Self-Mode in both apps. It runs Android Auto on the tablet itself so your phone doesn’t need to stay linked. It only works if the tablet has a working copy of Android Auto installed, which older tablets often don’t. Open Headunit’s developer also says that with Android Auto 17.4 and later you may need to start the head unit server from Android Auto’s developer settings before Self-Mode will run.

The real benefit is focus. Android Auto only supports a limited set of apps, so you can pause Spotify, skip a podcast or check a song title without being pulled into Instagram for half an hour. Messages can be read aloud and answered by voice, and on compatible setups Gemini can answer questions and even control smart home gadgets through Google Home, though that part isn’t always reliable.

In a car, the payoff is bigger. If your car lacks Android Auto, an old tablet or phone running the receiver app gives you directions on a larger screen without buying an aftermarket head unit, which can be costly or even affect a warranty. When navigation and music run together, the screen splits so the controls and the route both stay in view.

This is a hobby project, not a Google feature. Google’s official setup help doesn’t mention running Android Auto on a tablet at home, and the receiver apps come from independent developers. Expect the odd quirk.

• Your phone has to stay connected the whole time, by cable or wirelessly, unless Self-Mode works on your tablet.
• When it’s connected, the tablet won’t run its normal apps, and the screen can be dominated by a map even when you aren’t going anywhere.
• Anyone nearby may see your message notifications.
• Paid services still need their own subscriptions, such as Spotify Premium.

If all you want is Spotify or Google Home on a spare tablet, installing those apps directly on it is simpler. Android Auto earns its place when you want one calm screen that does a few things well.