Mirroring Smartphone on Car Screen

IMPORTANT! We assume that you are aware that any distraction while driving greatly increases the risk of an accident! Mirroring the smartphone on the car screen and using it while driving is your responsibility! We do not assume any liability!

The goal of this project is to mirror the screen of the smartphone on the car screen. In this post I will show you, step by step, how to do that. Once this step is done, I will show you how to use TrackExplorer in your car details in the blog TrackExplorer in the car. At this point it should be mentioned that this is a solution that is not available “out of the box”. You have to assume that – if everything works as planned – you will have to spend at least one whole day.

Everything that follows will only work with a rooted Android smartphone!

Requirements and Goal of the Project

We want to achieve two results with this project. On the one hand, we want to use the car screen for applications that are not available by default in Android Auto. On the other hand, we want to use TrackExplorer on the car screen.

Overview User Experience

When it comes to user experience, there are of course very different approaches. I describe here what is the most meaningful user experience for us. Of course, this may differ from your requirements. In the schematic below, we show you how we solved it.

We have defined the user experience for us as follows:

• Device (rooted smartphone Samsung S7) remains in the car
• As soon as I open the car doors, the S7 smartphone is supposed to turn on. Device is shut down/switched off before opening the car doors. If power is supplied via the USB port, the S7 smartphone should turn on.
• After I leave the vehicle, the S7 smartphone shuts down and is turned off.
• Smartphone S7 is connected to the car via USB. No Bluetooth connection between smartphone and car
• The Internet connection is provided by a hotspot. In our case, it is a Samsung S10. The S10 is connected to the car via Bluetooth. This means that I can make phone calls with the S10 via the car head unit. The phone (S10) is controlled via steering wheel or car screen, as usual.
• No calls are made with the S7 (contacts are not required)
• No calendar entries are displayed with the S7
• All Android Auto functions should be available
• Mirroring of the S7 display on the car screen
• Display during mirroring must be via a dashboard designed for cars
• Wish: Use all apps that are available in the Google Play Store. It remains a wish! Meanwhile, there are apps that recognize that a smartphone is rooted. Thus, for example, Sky Go, Netflix, … do not work with a rooted smartphone. But these are the exceptions. Most apps (about 85%) that we need work smoothly. Sometimes there is also a simple workaround, e.g. by installing an earlier version of the needed app. In our case, for example, we installed an older version (November 2019) of Amazon Prime.

Requirements – Mirror Smartphone on Car Screen

• Vehicle with Android Auto
  • in our case a Skoda Octavia 05/2020
• A rooted Android smartphone, e.g.
  • Samsung Galaxy S7 (no Edge)
    • Android 8
    • We recommend a device with these HW specifications. We also tested it with a Galaxy S5. Everything works, but the performance is weak (e.g. delays on the car screen when you tap on it). Apart from that, more and more apps need RAM memory larger than 2GB these days. TrackExplorer is one of those apps.
  • Second hand around 90,- EUR
• Approx. 20,- EUR for apps
  • Root Explorer (Optional)
    • We only needed this for the configuration, so that the smartphone turns on as soon as it has power at the USB port
  • Car Launcher Pro
  • Tasker

Instruction – Step by Step

Step 1 – Android Smartphone – Root

This is the most important thing! If your smartphone is not rooted, it will not work !

I do NOT describe how to root an Android smartphone. You can find a lot of information on the Internet. Of course, it also depends on which device you use. As already mentioned, we use a Samsung Galaxy S7.

Tip for Samsung: In the Android developer settings, before rooting, be sure to enable OEM unlocking!!! If you do not do this, the smartphone will be locked when rooting and you have to reinstall the original firmware (stock ROM). Finding the original firmware alone is extremely tedious! Here you can find more details about this topic How to Fix FRP Lock issue on any Samsung Galaxy devices?

In a nutshell: Before rooting, enable the OEM unlock setting.

Step 2 – Create your own Google Account

We can recommend that to you. Especially if you want to install Vanced instead of YouTube.

Step 3 – Install SuperSU

We use SuperSU. But you can use Magisk. It doesn’t matter, the main thing is that you have the ability to grant permissions to apps on your rooted smartphone. These rights are needed for the apps we use:

• AA Mirror
• AA Tweaker Patcher
• App Quarantine
• Root Explorer
• Tasker
• Vanced Manager

Step 4 – Android Auto Developer Mode

Before you can display AA Mirror in Android Auto, you have to activate the developer mode in Android Auto. In the settings at the bottom you have to enable/allow “Unknown sources”. Description how to enable Android Auto developer settings. Further for our project suitable settings in the developer options:

• App-Modus = Developer
• Day/Night = Vehicle controlled
• Deactivate ANR monitoring = checkbox is activated
• Video resolution = let car and smartphone determine resolution
• Unknown sources = checkbox is activated

Step 5 – Install and configure AA Mirror

Thanks to AA Mirror, you can mirror your Android smartphone on the car head unit. Settings for Samsung S5 and S7

Step 6 – Install and configure AA phenotype patcher

You need AA Tweaker for Android Auto to allow third-party apps like AA Mirror on Android Auto. After that, press the “UNPATCH CUSTOM APPS” button. If everything goes well, your smartphone will restart.

Step 7 – Install and configure the Quarantine app

As described in the “User experience” section, we do not want the S7 to connect to the car via Bluetooth. There is a setting in Android Auto where Bluetooth can be disabled. However, that did not work for us. To make sure that it works, we use the app Quarantine – Review App Quarantine

With App Quarantine we disable the Android Bluetooth services and the S7 reliably does not connect to the car. In the image below you can see exactly which services are involved – these three services are in quarantine:

Step 8 – First Test

Now is the time to test if the mirroring works in your car. Plug your rooted device with USB to your car and follow the instructions on the screens (smartphone and car).

We have heard and read that some users have problems with the connection or with Android Auto. This can be due to the USB cable or the Android app permissions, among other things. We cannot offer you any support at this point, because this varies depending on the smartphone and we have also noticed that some users despair at this point. This is simply because there are very different technical backgrounds or many user errors are made. When everything has worked, it looks like this on the car screen:

This gives you the basis to install and use almost any app on your car screen. In the TrackExplorer in the Car post, I’ll show you what apps we’ve installed, with a focus on TrackExplorer.

With TrackExplorer you can visualize your GPS data and display it in a 3D landscape. Both in real time and recorded GPS data. Details are described in the article Visualization of your GPX data.

Author: OJ