Hello,

I was wondering if any one's built an ARM powered MP3 player (preferably
running RO) for in car use? I would like to do this to replace or supliment
the radio/cassette in my van. I'm not sure I've got the knowledge to design
such a beast but I have the practicle skills (soldering, PCB etching etc) to
build one from a circuit diagram. If any one can offer any help/thoughts
please get in touch.

Cheers, Mike....

--
Michael Hambley - mike@armpowered.co.uk
http://www.armpowered.co.uk - My little corner of the web.

On 6 Oct 2006 Michael Hambley <mike@armpowered.co.uk> wrote:

Just about every MP3 player in existance is ARM powered. None run RISC OS as
far as I know. Your only option with RISC OS at the moment would be something
based around the A9Home, but it would be massive overkill compared to just
getting an iPod or similar.

---druck

--
The ARM Club Free Software - http://www.armclub.org.uk/free/
The 32bit Conversions Page - http://www.quantumsoft.co.uk/druck/

In message <7dcb9c714e.Michael@armpowered.co.uk>
Michael Hambley <mike@armpowered.co.uk> wrote:


I have also had the exact same thoughts recently, mainly because my CD
player in my Transit skips way too easily. It's got a line input on
2xphono leads on the back, so interfacing the audio output of a risc pc
is a doddle.

For control of the mp3's on the dash, I thought about a 2x16 module LCD
and a few push buttons mounted onto a silver coloured plastic panel
(I've got a panel under my radio where it's a double DIN hole).

See http://static.flickr.com/90/245409837_7ef05f7ad1.jpg

Perhaps a PIC micro to control the display (I've already developed some
PIC code to get some text onto a 4bit parallel LCD) and buttons and a
serial link from that to the risc pc?? Then you need some kind of mp3
database that displays what track is playing on the LCD display and
responds to the buttons on the panel... thts where I would struggle, not
having much luck with RISC OS programming.

The RiscPC would need to have a new PSU, a regulated 5v supply, 12V -12v
(I suspect -12v will be needed for the audio output- definately for the
RS232 port) and 0v lines. For testing purposes, an invertor could be
used, but it wouldn't be the most efficient use of battery power. In a
van a RiscPC case would fit in anywhere, under the passenger seats at a
push. In a car, it might be best to hide the gubbins in the boot.

This idea has already been done in the amiga world, although their
machines seem to need an mp3 decoding parallel port dongle.

http://www.hackaday.com/2005/02/18/...car-mp3-player/
http://amimpc.world3.net/

And specifically a display..
http://homepage.ntlworld.com/s.qure.../newhead01.jpeg

If I do get around to trying this, I'll probably do a little writeup,
like I did with the homebrew laptop.

--
Wes K (Moo-Juice) email: wakoneuk NOSPAM4ME<at> yahoo dot co dot uk
*** Remove the NOSPAM4ME bit and all will work fine ***
"Give me a big enough lever and I could move the world!"

In message <a75ca8714e.druck@druck.freeuk.net>
druck <news@druck.freeuk.com> wrote:


All the commercial in car units I can find on eBay just play MP3's off CD, I
want something that'll store them on an HD or some form of flash disc etc.

Agreed the A9 would be overkill (but loads of pose value ;-) and way out of
my budget (besides I'd want one on my desk to replace this SA RPC first!).
I'd prefer a proper incar unit rather than an iPod, besides I really don't
like Apple at all. I have a (relatively) cheap iPod Nano look-a-like MP3
player but it's buttons are rubbish and my radio/cassette doesn't have an
input to connect it to. I have treid one of those cassette to jack adapter
thingumys but the sound quality is apalling, loads of hiss and buzz, very
quiet too. The RF transmitter one's, I beleive, are illegal in the EU. The
current unit is unlikely to have aux. inputs on the back although I've not
had it out to check which I think would be my only other option for getting
auido in from my MP3 player. Any thoughts?


Cheers, Mike.....

--
Michael Hambley - mike@armpowered.co.uk
http://www.armpowered.co.uk - My little corner of the web.

In message <e993ad714e.wes@talk21.com>
Wes K <wakoneukNOSPAM4ME@yahoo.co.uk> wrote:


I don't have the luxury of a double DIN hole in my Astravan but I do have
quite a large storage hole a little further down:

http://www.armpowered.co.uk/a/apics/astra11.jpeg

I would then have to find somewhere else to put my shades ;-)

I will have to find out how to extract the factory fit unit and see if it
has any inputs on the back but as I said in another reply I think this is
unlikely.

[snip]


I have a nice area of space behind the seats, where the rear seat
passenger's footwell would be in the estate car, below the van loadspace
steel floor.

[snip]


Sounds good. If you do please can you keep me posted and I'd be willing to
help in any way I could. Please feel free to email me.

Cheers, Mike.....

--
Michael Hambley - mike@armpowered.co.uk
http://www.armpowered.co.uk - My little corner of the web.

Michael Hambley <mike@armpowered.co.uk> wrote:

Not RISC OS, but the commercial version of one of the first in-car MP3
players was ARM powered, by our very own Hugo Fiennes:
http://www.chaos.org.uk/~altman/mp3mobile/
(the original wasn't ARM, because Hugo couldn't find a suitable board in
1998)

Theo

In article <1737b1714e.Michael@armpowered.co.uk>, mike@armpowered.co.uk
says...

[snip]


It looks like a factory fitted unit, probably a CAR300.
No inputs I'm afraid and if you do remove it make sure you have the
security code (if you lose it, mail me and I may be able to help).

--
Greg Harris (Norwich)

On 6 Oct 2006, Wes K wrote:

[...]


You might find an MP3 CD player doesn't suffer from that problem
due to buffering, and they can be had reasonably cheaply.

I had one in my previous car (until the car was stolen) and I
never once had a problem with it skipping, including when I was
off-roading in the car - and if it was going to skip, that would
definitely be when it would have done so.

--
VinceH - http://www.softrock.co.uk/info/vinceh.html

Please sponsor me to abseil forwards down the Avon Gorge:
http://www.justgiving.com/vinceh/

On Fri, 06 Oct 2006 19:01:40 +0100, Wes K wrote:

I've been pondering the idea of an in-car player for a good 7 years, on
and off - I've never figured out a good way of doing the user interface
though such that it can manage a massive collection of songs but still be
usable by the driver without taking silly amounts of concentration.

I got as far as laying suitable cables for communication, power and audio
between the front and rear of the car when I replaced all the carpets
once, but that was it.

I suspect that any user interface has to be very well integrated with the
car to be really good - either steering wheel controls, head-up display,
voice control etc.

Either that or it's kept so simple that tracks are selected by simple
category rather than individually when on the move - but if that's the
case I may as well just stick the radio on tuned to a suitable station


I was intending to go the PC route for this, just because I had a
low-power board lying around; probably 4 bit parallel for the display like
you, and parallel input back the other way for switch input. I did toy
with the idea of using the guts from a keyboard for the switch input for a
while; I can't remember my reasoning for rejecting that now.


Not vastly efficient, but perhaps easier than trying to get regulated
+12V at useful current out of a supply that can duck below +12V
periodically under heavy load.

I always thought that inverters were expensive beasts, but I noticed the
other day that Wal-Mart here in the US sell 75W car inverters for a little
over a tenner, which really surprised me.

cheers

Jules

On Fri, 06 Oct 2006 20:05:34 +0100, Theo Markettos wrote:

Nice chap, too (I seem to remember picking up some odds and ends from
Hugo a couple of years ago - in particular, a Be Box, which is/was a
rather fantastic bit of kit!)