Less than a month after Elon Musk said Sentry Mode for Teslas would be "coming soon" the update has started to roll out, along with a couple of other tweaks. In a blog post detailing Sentry Mode, Tesla explained it uses the car's external cameras to watch for potential threats. If it's in standby, the cameras are watching, ready to go into an "Alert" state if someone does something like leaning against the car that pops up a message on its touchscreen saying that the cameras are recording.
If someone breaks a window or something then it goes directly into Alert, which activates the alarm, plays music at loud volume and turns up the brightness on the interior screen. It also sends an alert to the owner via their Tesla app and if they've plugged in a formatted USB drive prior to enabling Sentry Mode, then it will save a recording of everything starting ten minutes before the Alert was triggered. You'll have to turn on Sentry Mode each time you want to use it -- with its recordings that's probably for the best -- by going into the Safety & Security menu.
Sentry Mode continuously monitors your car's surroundings while it's locked and parked. When a potential threat is detected, the cameras on your car will begin recording, and the alarm system will activate. You will receive an alert from your Tesla app notifying you that an incident has occurred.
To enable Sentry Mode, go to Controls > Safety & Security > Sentry Mode. You must re-enable this feature with every use.
Sentry Mode is designed to add another layer of protection to your car, but it will not prevent against all possible threats.