Modern Car infotainment systems. How do they work? - Page 1
Forum section: electronics / general

author: Ed.Kloonk
author_rank: Super Contributor
timestamp: October 20, 2020, 02:12:35 am
content: Watching this video today,This car has 36(yes, 36) speakers. Monitors and touch screens everywhere. Even an intercom system. Baffling.I'd like to know what the system looks like, you know, behind the dash. Is it one big box somewhere with many looms or several sub systems?What comms protocols are used in between the interfaces?Care to speculate or illuminate?

author: brabus
author_rank: Frequent Contributor
timestamp: October 20, 2020, 02:25:03 pm
content: The key here is: bus architecture. A number of different protocols and buses are implemented in order to transport the different signals to the different units.For video signals, for example, GVIF (Gigabit Video Interface) is a very typical copper based bus; for audio we are talking MOST (Media Oriented System Transport), a plastic optic fiber bus in a ring fashion.Usually a single CAN (or FlexRay) connection is used between the infotainment and the powertrain, in order to gather information about the vehicle or send some commands (4x4 mode selection for example).There are mainly four units in such a setup:- Dash screen, usually pretty dumb and only dedicated to HMI;- Basis infotainment unit, usually the same along the whole vehicle portfolio. Navigation, connectivity and vehicle interface run here;- Rear seats entertainment unit, usually offered as an attachment to the main unit, in order to extend the functionality to the rear seats and let them work independently;- Audio amplifier. Usually separated from the rest and driven through a digital interface, such as MOST or even SPDIF.Many accessory units can be attached to the system, such as DVD players and even a Playstation. Vintage analogue signals, sich as CINCH stereo and composite are not rare here.In my experience, 36 speakers only lead to an increase of the fault probability. I had enough issues with my 12 speakers setup, when only 4 would abundantly suffice.

author: boz
author_rank: Regular Contributor
timestamp: October 20, 2020, 06:56:41 pm
content: More than 6 Speakers is just stupid unless you are doing active noise suppression.Car electronics are a big bug-bear of mine, replaced 4 computers converting my 5 series to electric. Just about all new cars are going to be unfixable after 20 years.

author: SiliconWizard
author_rank: Super Contributor
timestamp: October 21, 2020, 04:46:00 pm
content: Quote from: boz on October 20, 2020, 06:56:41 pmWell, you're being optimistic. If the fix involves any software patch - then that would be a lot less than this if the manufacturer ever disappears, or just decides to stop maintaining software.Now if the fix involves reprogramming flash chips, for instance (for failed chips), even with old, existing software, if this software is unavailable for any reason - you're also out of luck.If the fix involves electronic components (I guess that's mainly what you had in mind?) that are obsolete, then you're out of luck as well.I doubt even the 20 years, unless the whole electronics and software design was made open-source or something like that. Just my current thought though.

author: SilverSolder
author_rank: Super Contributor
timestamp: October 21, 2020, 07:27:09 pm
content: Quote from: SiliconWizard on October 21, 2020, 04:46:00 pmCars go obsolete a lot quicker than that. The industry specification / requirement is "10 years or 100K Miles". Even though most cars manage to beat that, try getting parts at the dealership if a model (or family) is > 10 years old... obviously parts that were used on later models will still be available, but if there was something specific to that vehicle, you are depending on luck.

author: tom66
author_rank: Super Contributor
timestamp: October 21, 2020, 08:33:02 pm
content: I have a fairly regular Golf and the infotainment system sits in the glovebox - in a roughly DIN-car-stereo sized format but with LVDS video to the main display and Ethernet/CAN bus interfaces to the rest of the car. The infotainment unit is made by Panasonic, and runs software by VW (based on a Linux/QT setup of some kind.)