The Promise of Wireless CarPlay

I’ve been a huge fan of CarPlay for 5 years and can’t imagine a car without it. Lately I’ve been reading about adapters to make wired CarPlay into wireless CarPlay. This sounded perfect as I wouldn’t have to take my phone out of my pocket and still be able to use CarPlay.

There are a number of devices out there that are basically hacks that make a car think that a wired device is plugged in and then have the iPhone talk wirelessly to it. None of how to do this is public knowledge and I doubt the manufacturers got Apple to reveal the secret sauce, so I knew things might not be perfect.

I decided on this device as it was small and supposedly had the latest hardware version. Installation was a breeze and I was amazed that it worked just like wired CarPlay except that there was maybe an additional 15 second startup time. Given the convenience of not having to plug in the phone, I could accept the delay.

I happily used the device for a few weeks on short trips around town and was pretty pleased with it. When we went on a longer trip, the device restarted after about 90 minutes. The dongle was warm to the touch and I suspect a big heat sink would mitigate the problem. In addition to restarting after awhile, the music was sounding garbled. At first I thought it was the streaming connection, but plugged in the phone and the issue went away.

One of the interesting, lesser known features of CarPlay is that if you have a garage door opener connected to HomeKit (I now use OpenGarage connected via Home Assistant, a button will appear on CarPlay when you are close to your house that lets you open and close the door. Why not just use the opener in your car, you ask? My wife has had a lot of problems with the HomeLink connected mirror triggering the door and kept sending me messages to open or close the garage. This feature, however, wasn’t working reliably with wireless CarPlay and I couldn’t pinpoint the problem.

After a bit of thinking about HomeKit and wireless CarPlay, I have a theory. HomeKit, when away from home uses a hub such as an Apple TV or HomePod Mini to communicate. When you’re on your local network, your phone talks directly to whatever device. Wireless CarPlay uses Bluetooth to setup a connection from the phone to the car (or device) and then switches to WiFi for the extra bandwidth. The car (or device) creates a private WiFi network for communication. Normally when apps talk to the network, they’ll try to use the primary interface (WiFi usually) and then failover to cellular if needed. When using wireless CarPlay, the WiFi connection always will fail and have to failover to cellular. This causes some delay and may be a bit unreliable depending on how long it takes to failover. Apple has an option called Wi-Fi Assist that is supposed to handle this automatically.

So while wireless CarPlay is a great feature, the dongle I purchased had some issues, but what really caused me to return it was opening the garage door; I was just tired of pushing the door button and not having it work.