[Android Head-Units] doitright:
That would be a *terrible* feature, since it means that the radio is far too isolated from the brainboard.

Properly designed unit will *NOT* reboot every time you start up. That is the feature you should be wishing for -- instant on without all the pointless rebooting.

That would be cute... for anyone outside of north/south america, africa, or middle east.

---------- Post added at 02:31 PM ---------- Previous post was at 01:43 PM ----------

Scratch resistant? Seriously? What are you doing to your dashboard that would justify this as anything besides pointless?

Light sensor is actually a really easy one, since it just amounts to a resistor.

No challenge there.... since bluetooth and usb gps dongles are easy to get and cheap. Even if your board doesn't have GPS, it is incredibly simple to add on.

We call that "unlocked bootloader".

I found a really nice little i2c board that can handle that stuff really easy.

Generally speaking, the lower the resolution, the better the performance. So I would caution against going overboard on the resolution.

One of the WORST things going for overall performance, are these super duper mega high resolution phone panels, the 2560x1440 AMOLED displays like the Nexus 6 has. While visually, it is gorgeous, the performance suffers in a manner you can see and feel. Nexus 5, for example, has much better graphical performance, since it is only pushing 1920x1080. I mean, think about it.... the Nexus 6 is pushing 3.7 million pixels, compared to the Nexus 5 pushing only 2.1 million. Its a double hit with the N6 though, since with an RGBG matrix, its effective resolution is actually much lower. Personally, I would have preferred a 1920x1080 *genuine* resolution, even at the 6". 1080p on a 5" phone panel is plenty of resolution. While you *might* be able to detect a hint of grain at 6 inches, it wouldn't be distracting, and WOULD be worth it for the performance boost.

But of course, those are at typically PHONE viewing distances, which are much closer than a car radio.

You hold your phone at what... about 16 inches? Car radio will be something like 24-30, maybe more?

Going by 5 inch screen held at 16 inch as a reference, based on the angle that the screen diagonal points make against your retina, that would match up to a 7.5 inch screen at 24 inches, a 9.4 inch screen at 30 inches.

So lets scale that 9.4 back to a 7 inch, starting with 1920x1080.

You would be looking at 1430x804.

But how about if you hold your phone at 12 inches?

Now your dashboard "equivalent" grows to 10 and 12.5 inch.

Scaling that 12.5 incher back to 7 inch yields an equivalent of 1075x604.

Even at 24 inch, you're looking at 1344x756.

So that really starts to make 720p 7" panel look like its in the same ballpark as a 5 inch phone with a 1080p display. The question then is this; do you really notice the resolution of a 5 inch 1080p display? Even if you look really close and try to focus on individual pixels?

"THEY" (being aftermarket hu makers) say that a DDIN panel over 480p doesn't make much sense visually for car HU distances. I would be inclined to argue this point, since I have a couple of cars with 480p DDIN panels, and they are a bit grainy.... but I have been working with a 220 dpi display, and at those distances, it is way more than enough. That's a 7 inch panel at 1280x800, which is pretty much the physical limit for fitting into an approximately DDIN space. If you have room for a larger screen, then of course you will want a greater resolution, keeping with a sensible DPI. Realistically, for automotive application, make your target 160 DPI. Exceed that by the smallest amount possible in order to maximize performance without degrading visual quality.

FWIW: The panel I'm working with accepts a wide range of input resolutions, including "hdtv" 720p and 1080p. Of course, native resolution will always be the best visually, especially when you are looking at a different aspect ratio, but focusing specifically on *performance*, when I'm feeding it 1080p (2 million pixels), the display output grows slightly annoying in terms of choppyness. Output is beautiful at 1280x800 (1 million pixels), and the resolution is high enough that I wouldn't be able to tell if the pixel density was higher.