[Rhombuss]

I have a dead Samsung NEU64MB player here that I just recently opened up and removed all the non-essential casings and stripped it down to the bare PCB and chips. I'm thinking of building a slightly larger enclosure for it and using it as a car MP3 player.

Just have a few questions though - I'm not really a car fanatic I lack some technical knowledge that I'll probably need.

Would I use some type of transformer to be able to tap into the car battery? The mp3 player uses double AAAs, so that's what - 2x 1.5V = 3.0 V. Some clarification on how this would be done would be great. Here's a picture -

- of the positive and negative battery terminals on the PCB. There's s little junction between the two that says "100, 7p", could that be an indicator for the voltage regulator?

Also - what type of audio jacks to typical cars use? I'm assuming the large RCA jacks? That's no problem as I can easily get a converter.

Finally - what type of bays do car stereos use?

Thanks!

 

[stereth]

You might want to try diyaudio or audioasylum for this. I don't know what kind of connector they use. Your best bet would probably be to buy an old, broken car radio. Then you have your connector plug (which, I believe, handles power and audio out) and a case of the right size.

For power, check your player's PCB. See if it has a voltage marked on it, like "2.4V" or something. That is the voltage your player actually runs on. Most regulate whatever input voltage down to that. So it wouldn't be a problem to feed it 5 or 8V. Probe around that connector with your car on and see if you can find some voltages.

 

[rickcr42]

locate the fuse bloch for your car and tap in to the car battery 13,5 volts there using a 12 guage or so wire

at this point use a LM317 three pin voltage regulator and set the voltage to 3 volts or so . From the regulator output terminal to the regulator input terminal connect an IN4001 rectifier ,anode end to regulator input pin

on input side of the reg chip add an 0.1 uf/50 volt monlithic ceramic capacitor

on the output side use a 47 uf solid tantalum cap

follow this with an L/C "Pi" filter to suppress noise from the alternator/ignition system and an IN4001 rectifier from the + rail (anode end of rectifier) to ground (cathode end) and finally a 1/4 A fuse

conecct to the mp3 player with 24 guage or so wire

rickmeister

 

[Rhombuss]

Woah rickmeister - that's pretty detailed. Could you explain what the parts are for? I'm pretty inept about electronic parts - I know the basics about circuitry but you lost me at the rectifiers, monolithic capacitor, and the solid tantalum cap .

 

[rickcr42]

hehe,yeah , Can do

the rectifiers are just rectifiing doides , a generic part found at radio shack for like a buck for two

rat shack also carries the regulator chips and the tantalum caps though I am not sure about the monolithic ceramics

the reason i stated that particular type of ceramic cap is if I had just said ceramic you would have just grabbed a ceramic disc cap of dubious origin and those babies can be leaky as hell and more often than not not marked correctly in value

the same with the tantalum-if i just said tantalum .............


same thing

the diodes are for reverse polarity protection which is essential in autosoud systems due to all kinds of weird crap happening on startup/lights/windshield wipers/etc

the Pi filter is for all the garbage ,noise,etc. on the voltage line and this will give you a clean signal : garbage in-garbage out !

the fuse is a backup safety mechanism to prevent a damn fire

(Been there ,done that

)

I came up with these values from memory but i will check and see if i can post a schematic that will carify things

rickasaurus-rex

 

[Rhombuss]

Ahh, that clears things up a bit - a schematic of where things would go and how they would be oriented would be GREAT! I'll most likely mount the MP3 player permanently in the casing, and just use a smartmedia card (which is supports) as my means of swapping media in and out. I'll definitely rewire all the buttons and LEDs on the actual player PCB and re-route them to the casing front, so technically the player will just be sitting inside.

 

[Rhombuss]

Actually, I was poking around on Ebay and found a bunch of auctions for broken or non-functional car audio equipment, like in-dash CD players and the like. I was thinking I could purchase one of these dead units, and hoping that the power circuitry still works (which supplies 12V I believe), I could just strip all the insides and rewire the access panels to what I needed. If I mounted it correctly, I might even be able to use the CD slot as a loading location for my Smartmedia card.

Anyone think this doable/not doable?

 

[stereth]

Go for it. Let us know how it goes.

The LM317 is a positive voltage regulator. Radio Shack sells them. On the back of the package, and in the data sheet if you look online, it shows you how to hook up a circuit to get the output voltage you want.