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ars edited this page Aug 31, 2026 · 10 revisions

Wireless Android Auto

Open Headunit allows you to connect your phone wirelessly via WiFi. In addition to standard network connections, the app now supports Wi-Fi Direct (P2P) for a seamless experience without needing a shared hotspot.

Prerequisites

  • Phone: Android 10 or higher with Android Auto installed.
  • Head Unit (Tablet): Android 4.1+ device with WiFi.
  • Network Options:
    • Wi-Fi Direct (P2P): (v2.0.0+) Best for stability. No hotspot required.
    • Shared WiFi: Both devices connected to the same external router or mobile hotspot.

Important

Android Auto 17.4+ Compatibility Notice: Starting with Android Auto 17.4, Google has restricted background wireless startup triggers, breaking automated launch via Wireless Helper and third-party launchers, as well as classic Self-Mode. For Android Auto 17.4 and newer:

  • Self-Mode: The only remaining solution is starting the native Headunit Server from Android Auto Developer Settings.
  • Wireless Mode: Use a USB Wireless Dongle, Native Mode, or the Headunit Server.
  • Wireless Helper: Continues to work reliably on devices running Android Auto 17.3 or older.

Connection Modes

1. USB Wireless Dongle (Most Reliable)

A dedicated hardware USB Wireless Android Auto Dongle plugged into your headunit / tablet provides hardware-level plug-and-play without relying on Android Auto startup workarounds.

2. Native Mode (Wi-Fi Direct & Headunit Hotspot)

Open Headunit implements the native Android Auto wireless handshake protocol directly.

  • Supports Wi-Fi Direct (P2P) for direct peer-to-peer connection without an external network.
  • Supports Headunit Hotspot mode where the headunit acts as the AP.
  • Configure in Open Headunit Settings under Android Auto Mode -> Native Mode.

3. Headunit Server (Developer Mode - Required for Self-Mode on AA 17.4+)

Uses the built-in Android Auto developer server running on the phone (or on the headunit itself for Self-Mode).

How to setup:

  1. Enable Developer Mode: Open Android Auto Settings on your phone -> tap Version 10 times.
  2. Start Server: Tap the three-dot menu in the top right corner and select Start headunit server.
  3. Connect: In Open Headunit, tap the WiFi dashboard button (or select Self-Mode).

4. Wireless Helper (for Android Auto up to v17.3)

Our companion app triggers projection automatically when entering your vehicle.

  • Compatibility: Android Auto v17.3 and below.
  • Download: Wireless Helper on Google Play
  • Setup: Set Open Headunit to Helper Mode, connect both devices to the same network or Wi-Fi Direct group, and start the service in Wireless Helper.

Technical Details: Android Auto Developer Mode

To use the Headunit Server, enable the native developer server on your phone:

  1. Enable Developer Mode: Tap "Version" in Android Auto settings 10 times.
  2. Start Server: Tap the three-dot menu (top right) and select Start Headunit Server.

Wi-Fi Direct (P2P) Setup

  1. In OpenHU Settings, ensure Wireless Mode is set to Helper Mode.
  2. In Wireless Helper on your phone, set the mode to Wi-Fi Direct.
  3. (v1.5.0+) You can now enter multiple target names if you use different tablets. The default is OpenHU.
  4. (v3.1.1+) Static BSSID (Optional): If your phone fails to auto-detect the tablet due to Android 12+ MAC address restrictions, you can manually find your tablet's P2P BSSID (MAC Address) and enter it in Open Headunit Settings under Static BSSID:

How to Find the Tablet's P2P BSSID (MAC Address) Manually

  • Method 1: Using a Wi-Fi Scanner App (Easiest)

    1. Start the Wi-Fi Direct group on your tablet.
    2. Install a free Wi-Fi Analyzer/Scanner app (such as WiFi Analyzer by farproc) on your phone.
    3. Run a scan in the app.
    4. Locate the network starting with DIRECT- (e.g., DIRECT-xx-OpenHU). The app will display its BSSID (MAC address) right next to the SSID.

  • Method 2: From Phone Wi-Fi Connection Details

    1. Manually connect your phone to the tablet's Wi-Fi Direct group once.
    2. On your phone, go to Settings -> Network & Internet -> Wi-Fi.
    3. Tap the settings gear/info icon next to the connected DIRECT- network.
    4. Look for the BSSID or Access Point MAC address entry.

  • Method 3: Using ADB (For Developers / Power Users)

    1. Connect the tablet to a computer via USB and enable USB Debugging.
    2. Open a terminal/command prompt and run: 
      adb shell ip link
    3. Locate the interface named p2p0 or p2p-p2p0-0.
    4. The MAC address listed next to link/ether (e.g., ee:2b:eb:74:e1:ec) is your P2P BSSID.

Troubleshooting

  • H.265 Artifacts: Update to v2.1.0 for optimized 4MB buffers and NAL parsing.
  • Connection Drops: Ensure you are using 5GHz WiFi for high-bitrate streams.
  • Audio Issues: Ensure Audio Sink is enabled in Settings if you want sound on the tablet.

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