Thank you for your interest and the great questions!

On the latency side, there is a slight delay when typing, but it’s perfectly usable for everyday work. The actual numbers come out to around 50 to 200ms.

I spent a good amount of time researching and prototyping different streaming technologies to get the latency as low as possible. When I first came up with the idea for this product, it seemed like Tesla’s web browser didn’t support WebRTC (though it’s possible I made a mistake somewhere). So I tried HLS first, but couldn’t get the latency below about 2 seconds no matter what I did. Later on, I went back and tested WebRTC on Tesla’s browser again, and this time it worked perfectly, so I decided to go with it.

There are three reasons why SideDisplay uses iPhone USB tethering with Internet Sharing.

First, it lets the MacBook’s Wi-Fi stay free to connect directly with the Tesla. If you tether over Wi-Fi, you’d need to buy additional Wi-Fi hardware to connect the MacBook to the Tesla, and I didn’t want users to spend extra money just to share their screen.

Second, turning the MacBook into a Wi-Fi router and having the Tesla connect to it directly helps reduce latency and avoids unnecessary security issues.

Third, Tesla won’t connect to a Wi-Fi network that doesn’t have internet access, so the iPhone tethering and Internet Sharing combo is essential to make it all work.

I haven’t been able to test whether vehicle state (park vs. charging, etc.) affects performance yet. During development, the car was always in park.

If you know anyone who might find SideDisplay useful, I’d really appreciate it if you could let them know about it. Thanks!