New Project. Raspberry Pi Stereo

[HankScorpio]

After shopping around for a decent car stereo, I've bitten the bullet and decided to build one with a raspberry pi and the official 7 inch touchscreen. Going to use Openauto which is essentially an android auto emulator.

Mechanical engineer by trade and fuggin hate anything computery, so could be a steep learning curve. The plan is to get it working on the desk and then stick it in the Death Star. Will be stereo to begin with and then I'll be looking to make it 5.1 surround.

Hope to bring the whole lot in for around £200 - £250. Spent the last few evenings researching it and it looks possible. Glad I work with a load of computer, electronic and manufacturing engineers as I think I might be keeping them busy.

Anyone else given this a go?

[ThomasG]

Maybe not exactly giving it a go, but definitely giving it some thought.

Frankly, not something I was to properly look into until winter at least, and initially I was thinking about employing Linux - I can't find any half decent app for android, paid or not.

I'll keep an eye on your thread.

[ThomasG]

Got few minutes, so few things that make me think about it the way i do.
I hope you`ll find some of it useful. Or someone looking for such information.

Android:
By now, the best App i`ve found would be Agama car launcher..
That is to say- best, but nowhere near sufficient.
Why:

Its an app that is capable of launching other apps. It has very little of ability to interact with launched apps, though.
What it means in practice, is that one can use it to launch, for example, internet radio streaming app, OR music playback (SD card with mp3 for example)
But only to launch it.
to start playback, one needs to choose playlist or stream or even a mp3 file separately, from within the given app (lets say music player) that has its own graphic interface, not necesarily car-friendly.
so instead of loking at the road- one fiddles with whats on screen.

then there wil be time when one wants to change, for example, from mp3 playback to internet radio stream.
on "old" car stereos, of any make, when one wants to change from for example CD to RADIO, it is a matter of pressing ONE button.
Not so in Android.

One needs to stop playback on first app, then switch to "home screen"(agama for example), then start another app, and then tell it what to play.
otherwise one will end up with 2 apps playing at once.
have you ever heard 2 songs played at once from one set of speakers?
here`s your chance.

so again- instead of keeping eyes on the road, one fiddles with touchscreen..


in the meantime.....

linux..

there is lots and lots of audio and even audio/video multifunctional apps.
that is- ONE app that can do it all.
for example an app called QMMP.
would you remember something called "WinAmp">

QMMP looks and acts pretty much the same.

one can create playists with esy access, for example.
one can make first playlist with few radio stations
second playlist with.. lets say R.E.M. album sitting on SD card
third playlist with Chopin album on SD card
fourth playlist with few kids movies on SD card (longer journeys)

and so on and such like.

and with each change between "source", that is - playlist: playback of previous one will stop automatically.
as close to "one button" as possible.

then there is the look of it.
in its original state, QMMP isn`t too much of a "car friendly thing"

but then- it supports SKINS

so one can change the looks of it by downloading skins from internet, and if there is nothing that suits- creating a skin will be hell lot easier than creating a full android APP that would dot the same job.

and thats how far i got by now with regards to audio section.

other benefits:

Linux by itself supports several desktops, that can be displayed on one screen.
kind of like it is on a smartphone.

so one can set, for example, first screen with audio control (that QMMP or any other, its a big big world of apps available), second screen with for example Linux version of Torque app (and OBD ELM reader connected by USB), third screen with satnav and so on and such like...

and there`s no reason why linux cant be run on raspberry.
as it happens- the very android is based (quite literally) on linux.
to avoid, or maybe create, some confusion- android IS NOT linux. it only sits "on top of it", whilst linux underneath does all the job for it.

but thats a completely different story, for different post.

[ThomasG]

Oh, one more thought:

with Android, be rady to spend some time IN the car, every now and then, setting it up.
Literally sitting in passenger or driver seat, whilst parked, and tapping the screen to set this or that.

with linux you can do that too, and you have option of connecting a keyboard and a mouse..
but even better- you can park your car close to home, get it to connect to your WiFi, and go home.
do it all from your laptop/desktop, via remote login, sitting by your desk.

[Max HEADVROOM]

deffo following this.. i hope your going to include gps?

[JoeNinety]

Have you seen Crankshaft OS ?
https://getcrankshaft.com/

[revaido]

I ran a Pi in my XC90 with Kodi plugged into the rear screens so I could load it up with entertainment (films and music) for the kids.

It may sound counter productive but I had to step back to using an older Pi 2 for reliability - the 3 and 3B I had both rebooted occasionally I'm assuming due to power fluctuation issues.

I was playing with a 4 2GB yesterday and the heat these new ones produce at idle is bonkers but it's certainly fast. I tried using it for some SDR duty but the 4 needs time to fix some driver issues as some USB devices aren't playing well with the VIA USB chipset they're using now.

If you do get random issues try and make sure it's got the cleanest power possible.

[HankScorpio]

Thanks for all the responses guys, very useful to know (and equally useful to know who to ask questions to).

This just arrived. Waiting for screen..... And wondering where all my SD cards have gone.

[ThomasG]

Originally Posted by HankScorpio

Thanks for all the responses guys, very useful to know (and equally useful to know who to ask questions to).

This just arrived. Waiting for screen..... And wondering where all my SD cards have gone.

Good luck!

and keep us posted.

on another note, and NOT trying to hijack the thread (when time comes, I`ll open new one)
because of you i started thinking a bit more about what will I want from carputer..

graphics and control:
Easy, touch screen ONLY as fallback
prefferable control by dial and as few buttons as possible (similar to that dial as they fit in these ugly BMWs)
i think turn the tial- selecting option
pressing the dial- choosing that option
separate "back" button
and 2-4 buttons to change main function(audio/video/GPS/OBD)

as for GUI- the "home" GUI of KODI would be about right, but...
If anyone has seen kodi, he/she knows there is the main bar in the middle of the screen, and that would be easy to operate with dial+press+"back", but..
there are things in there like side menu, like these buttons at the bottom of the screen etc.
these may not be as easy to operate with just the dial

also KODI will not support anything resembling satnav or OBD.
it simply wasnt built for it

yet there may be a way around it
if each main function with its dedicated physical button has its own, dedicated desktop..
one desktop could be running KODi
second SatNav
third OBD (secondary thinking about this one, will elaborate later)
and so on ans such like

then to operte properly, such a device would need to know various states of the car
parked with engine off and key out/locked up
unlocked whilst waiting for someone (for example on airport pickup run- sometimes i just sit there watching a movie)
car actually running

etc

that could be established by reading some electrical values from the car itself:
state of "switched live" of original HUD unit
state of switched live for headlamps (allowing to change GUI to "noght mode")

but to read such, the carputer would have to have some king of I/O module capable of reading such states and forwarding these as data over USB.
could also fit a small relay or twoto accomodate some other things- like keeping carputer alive whilst car parked and locked up but wifi access needed

then by sending a command over the wifi, carputer would be able to switch that relay and essentially- send itself to sleep, dropping the WiFi connection (and making the possibility that someone would hack into it overnight less possible)

that OBD function..

could display it on the main screen, but if possible- maybe as a HUD?
it is possible to run 2 separate screens off one computer, why not to have one fitted in the centre console and another on top of dashboard, "projecting" onto windscreen?

so, what would be needed would be a low-power computer, either capable of running directly from cars 12V supply or with ability to build/obtain a power supply unit that can be fitted as intermediate,
unit with at least 4 USB ports (1-I/O module for power/relays, 2- GPS receiver, 3- unless built in- WiFi dongle, 4- flas drive with media, fitted to the front of unit, or behind armrest..

thats the main bit

then screen or two (if HUD option), one of these maybe even touch screen

a dial with panel of buttons

lots and lots of software tailoring

lots and lots of thinking and planning

lots and lots of preparation

mooonths away

i`ve got more immediate things to do before that

[HankScorpio]

I think I might have to review that one again after sobering up from the half litre of gin I've just got through .... Although I still might have to pass it on to work guys. Pi 4 does come with 2 mini hdmis though.

Got to take one of the small ones to a football tournament early tomorrow, I'll try to take it all on board then (can't wait for the rugby season to start again, I'm a coach and theres nothing to clear a hangover like shouting at a load of 9 year olds )