Open Headunit Lets Old Android Tablets Serve as Android Auto Head Units

Android Auto connects a phone with a car and displays a driving-friendly version of Android on the car's touchscreen infotainment system. Many vehicles, especially older ones, do not support it. According to Engadget, relying on a regular Bluetooth connection to a phone for navigation and entertainment means putting a tablet in the car as an Android Auto interface could be a significant upgrade.

Getting Open Headunit running requires some fiddling. The app allows multiple connection types, including USB, Wi-Fi, Bluetooth and running Android Auto directly on-device if the tablet supports it. Users need to experiment to find which combination works with their hardware. The tablet also must be connected to the car's audio system to play music or other media. Open Headunit has a built-in configuration tool that walks users through the most important settings, and Gemini in Android Auto is supported.

In Engadget's testing, wireless Android Auto issues made USB the easiest solution. After enabling the various permissions for Open Headunit and making it the default for USB connections, plugging a phone into a Samsung Galaxy Tab S10 Ultra reliably opened Android Auto and resumed playback on Spotify through the tablet's speakers. Connecting the tablet to the car's Bluetooth allowed audio to pipe through the car stereo, but that created too much latency. The reviewer reduced the delay by using a small USB-C hub with a 3.5mm headphone jack, then wiring an auxiliary cable from that into the car's own 3.5mm jack.

Performance was great on the tablet, but Engadget noted it is a high-end unit only a couple of years old. The publication was not able to test Open Headunit on older hardware. A 2013 Nexus 7 got stuck in a boot loop, and a 2019 Galaxy Tab S6 Lite experienced a display malfunction. Neither recovered by filing time. The article said all processing for the test was done on the phone, with the Open Headunit app simply fooling the phone into thinking the tablet is a car.

Engadget also noted that users might not want to leave a tablet visibly mounted in a car, since even an older tablet may be a target for thieves. The reviewer uses the tablet as a primary computing device, so if sticking with Open Headunit long term, the plan is to install multiple MagSafe car mounts in a row on the dash and stick multiple magnet rings on the backside of the tablet, or use one of the many car tablet mounts available on Amazon. For now, the tablet sits propped in the tray area below the car's actual head unit when Open Headunit is running.

The solution is not perfect, according to Engadget, but it is much cheaper than buying a new head unit for Android Auto, especially for those who already have a tablet. If a car's stock head unit has quirks that make it particularly aggravating to replace, Open Headunit is a decent way to avoid that experience. The reviewer's 2015 Subaru head unit failed a couple of years ago, and replacing it through an official dealer would cost over $2,000. He could buy his own Android Auto head unit and install it himself, but after looking up guides, he said it is not something he will have time for in the near future.