In Car Speech Enabled MP3 for... £20?
 

Right then fans of being on a budget, here's a wee project I've just started tonight which I think might be of interest!

I decided I'm fed up with hooking my mobile phone to the car for music; the media player on Symbian Belle is just such a stinking pile of crap... What I really need is a fancy MP3 playing head unit! Eh, except Volvo didn't make any that'll fit in my 850 and I don't fancy hacking the dash up to fit an after-market OR paying for a new head-unit.

Now, of course, I could just buy a cheap MP3 player and hook it all up with cables coming out the side of the unit and a power adapter from the ciggy lighter. A couple of reasons why I won't; it'll just look like crap and also unless I remove ALL this stuff from the car, someone'll think that I've got an expensive sat nav in the glovebox and break in.

There's also the added problem that a lot of the power adapters for the ciggy lighter pass on ignition whine to audio devices. (both my phones suffer this to a degree)

So, I want something permanent, functional and powered by a good clean power source?

This could be a job for... Banging something together really quick like!

---------------------------

After extensive research (10 mins on google) I decided on a Sandisk CLIP+ MP3 player. It's teeny tiny, comes with 8G of storage on a removable SD card and it can run ROCKBOX, the freeware operating system for MP3 players that has a whole bunch of awesome features: the top one being it can SPEAK the menus and options to you. That's a good idea for a car environment, eyes on the road and all that.

http://www.rockbox.org/

I installed it on the CLIP, as per the instructions:

http://www.volvoforums.org.uk/attach...1&d=1333151732

And then spent about 30 minutes trying to remove the two parts of the case that holds the device together! It argued with the stanley knife for quite a while, but eventually the knife won; one CLIP, unclipped!

I removed the switch blank down beside the gearbox selector (that's where I intend to put this device) and glued the outer housing onto it:

http://www.volvoforums.org.uk/attach...1&d=1333151732

Right, that's the simple bit done... The next part was a total buttock.

It's my intention to hook this up permanently to the car, so I decided to utilise the existing AUX IN mod on the head unit, but with a twist: I'll also draw the +5 USB power for the MP3 player from there too.

Right, so I need to HARD WIRE this device, remember.

http://www.volvoforums.org.uk/attach...1&d=1333151732

Now before you ask, yes I am a level-2 certified SMT rework specialist, but if you have a steady hand and are good with the soldering iron, anyone could do this.

As you can see, I've de-soldered and removed the original 3.5mm output jack: there'll be no need for it in the new circuit.

I hooked up the three connections for audio (L,R,G) and two additional ones for Power Ground and +5v. +5v was the hardest as there's next to no clearance to get the iron in, but eventually perseverance paid off and it soldered on OK.

I'm using twisted pair wiring here, which isn't wonderful for audio, but as it's solid core it's much easier to solder to tiny components. With the distance of the cable run we are dealing with, I don't think audio quality will suffer enough that I could hear the difference. Notice I've wired TWO ground wires together for the audio, to maintain the individual twisted pairs.

http://www.volvoforums.org.uk/attach...1&d=1333151732

Hurray!

Ok, so that's as far as I've got this evening. Tomorrow I'll be looking at installing it into the car and the associated wiring and if I survive, I'll post about it and let you know how it goes! :)

Chris...

Lookin' good. Keep us posted.

Hello

This is fascinating!

Some really stupid questions:
How will you add new music to the player? Will you be able to pop the memory card and take it away for reloading?

Yep, two options there;

1. Bring laptop into car, hook up and dump data.
2. Remove 8gb SD card, take in house and dump data on. (Think I'll use that option) :thumbs_up:.

The card is a really nice 'press in and clicks to lock, press and clicks to eject' type of mechanism so no danger of it falling out or breaking with use.

Chris...

Ok, so I got a lot done yesterday and last night!

I tested out the PSU on the head unit and found that the +5v line I was looking at outputs +5.04v with almost perfectly stability and regulation. Looks like a very nice clean waveform on an oscilloscope so I figure it's perfect!

First, I finished up the cabling on the MP3 player:

http://www.volvoforums.org.uk/attach...1&d=1333291595

Here I've got a standard male USB connection to carry the 5v and a standard headphones type shielded twin core to carry the audio.

http://www.volvoforums.org.uk/attach...1&d=1333291595

Here I have added the USB power cable to the head unit. You'll find a +5v and 'P-GND' towards the top of the riser connector. Solder the black cable to GND and red to +5v pins. Easy!

I've added some hot melt glue over the connections for strength. You could use potting compound or even a good section of electrical tape.

http://www.volvoforums.org.uk/attach...1&d=1333291595

Here's the female connector for the USB power. The power output from the head unit looks to be good for about 600ma, so this more than meets the 500ma specified in the USB specs and certainly exceeds the 150ma the MP3 player uses.

Ok, so then I put it all into the car and hooked up the audio cable. Sucess!! That part works.

Then I put on the USB cable and ran straight into a brick wall. The USB power was clearly bad and the MP3 player's audio cut straight out. :(

After much scratching of heads, muttering and dicking around with checking connections, I eventually figured out I seemed to have some sort of a ground loop fault which was making the MP3 player's amp oscillate.

What I need is a fully isolated PSU with filtering caps, inductors, etc etc etc

Well, that sounds like work and expensive, so on a hunch I removed the power ground connection from the MP3 player... And it all worked perfectly! MP3 charging, music playing, great audio quality.

I guess the MP3 player just couldn't handle having two ground (audio and power) grounding connected at once for whatever reason, so cutting it down to one did the trick.

http://www.volvoforums.org.uk/attach...1&d=1333291595

Here's where I decided to put it in the end up. I figured this is best, because I thought if I put it somewhere in the driver's line of sight the temptation would be to READ it while it's operating... Which would be pretty dangerous while driving.

Where it is all the controls can be operated very nicely and the menus are all read out, so no need to physically look at the device while it's in operation.

http://www.volvoforums.org.uk/attach...1&d=1333291595

Hurray for LolvoToonz!!

Chris...

Here's some video of it in action:

http://youtu.be/12Eob0B5NBs

:thumbs_up:

Chris...

Hello

I won't be trying this - way beyond my expertise!

I'll have to make do with the bluetooth connection between my phone (16gb of memory, so plenty of space) and my iO Play.

That's a really elegant solution. Hats off to you for your ingenuity!

Nicely done fella. I do admire adaption of standard equipment to suit personal needs..:thumbs_up:

Wow, that is all so clever, way beyond me.
As I understand it you have set out to play MP3 through your standard Volvo fitted radio.
I did this in my car by buying a Belkin Tunebase, plugging into my cigar lighter socket and tuning in the car stereo to pick it up. Works beautifully and so much easier for the unskilled solderer. Link below.

http://tinyurl.com/c7jnhq2

That is a neat looking finished project, nice to see what can be done instead of putting up with what just the manufacturers have to offer. You have now me interested in doing things to the V70 head unit. One has to have an inventive mind just like my colleague used to fit small transistor radio parts into these old 1930`s wireless sets, the valves lit and everything and it also had VHF!!
I myself repair old reel to reel tape recorders which is also an interesting pastime.