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MP3 Player — Parallax Forums

MP3 Player

GoogGoog Posts: 65
edited 2006-06-26 19:57 in Propeller 1
Anyone developing code for an MP3 player? That would be fun.· Just thought I'd throw it out there because I'm in no boat to start that project (I'll be buried in my Commodore emulator for some time), but I sure would like to see it happen!

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Doing my part to keep the Commodore 64 alive!

http://www.commodorestuff.com
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Comments

  • Kaos KiddKaos Kidd Posts: 614
    edited 2006-06-23 19:34
    Goog...
    I have almost the entire project layed out...
    screens, the player, and basic operations...
    here's a link to the actual player my son and I are building...
    ( http://www.pjrc.com/tech/mp3/sta013.html )
    Total cost of the player is real low...
    I'm working on the storage subsystem (hence all the pffft about USB, SD storage stuff)...
    Once I get the storage worked out, it's nearly a drop and go issue...

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    Just tossing my two bits worth into the bit bucket


    KK
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  • GoogGoog Posts: 65
    edited 2006-06-23 20:04
    Kaos (any relation to Get Smart's evil organization?)...

    That is great, but how about writing the code for the decoder? That would reduce the number of chips/hardware, right?

    Goog

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    Doing my part to keep the Commodore 64 alive!

    http://www.commodorestuff.com
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  • GadgetmanGadgetman Posts: 2,436
    edited 2006-06-23 20:44
    Decoding .MP3 files is not a trivial task...
    Decoding and D/Aing the results before pumping it into an amplifier is even trickier.

    Just because something may be possible to do in software doesn't mean you have to do it...

    And the chip-count would only be down by one, if that(you'd probably need a D/A chip at least), so there's not that much to save.

    I may get that chip myself, and dump a couple of .MP3 files onto EEPROM or SD for use in my car.
    (Warnings about open doors/windows, low fuel/empty window-cleaning fluid reservoirs/overheating, all that stuff. Music will still be my iPod or CD-changer)
    Saves me from switching on a 7" LCD, which can be a bother, particularly at night.

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    Don't visit my new website...
  • GoogGoog Posts: 65
    edited 2006-06-23 20:55
    That chip has a built-in D/A converter, too... so I guess it wouldn't be that bad.

    Gadgetman, are you saying that you'll use the prop. chip in your car to give you car status information?
    Gadgetman said...
    Just because something may be possible to do in software doesn't mean you have to do it...

    Sure it does smilewinkgrin.gif That's what keeps us software guys busy!turn.gif
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    Doing my part to keep the Commodore 64 alive!

    http://www.commodorestuff.com
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  • Paul BakerPaul Baker Posts: 6,351
    edited 2006-06-23 22:26
    According to this page the DAC is external for the STA013.

    Here is a chip that has an onboard DAC and headphone amp: http://www.sparkfun.com/commerce/product_info.php?products_id=305




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  • GadgetmanGadgetman Posts: 2,436
    edited 2006-06-23 22:33
    Goog said...
    Gadgetman, are you saying that you'll use the prop. chip in your car to give you car status information?

    That, controlling the central locking and whatever little management task I can think of...

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  • GoogGoog Posts: 65
    edited 2006-06-24 04:22
    Cool! Are you interfacing through OBD2? Or are you just replacing the car's on-board chip? Or just adding a whole new system?

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    Doing my part to keep the Commodore 64 alive!

    http://www.commodorestuff.com
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  • GadgetmanGadgetman Posts: 2,436
    edited 2006-06-24 10:51
    I'm NOT touching the ODB2 system at all. I will hook into those sensors I can but I won't touch anything that can endanger the running of the car.
    (I mounted an 'economy gauge' in one of my previous cars, and what that did to the fuel-economy... AARGH!)

    I can mess around with the central locking because the car doesn't have any, yet.(I'm putting in an 'el cheapo' system I bought, piece by piece as I get time)
    I will add a 1-Wire reader on the driver's side somewhere so that I can use an iButton as a key, too.
    (Anyone having experienced a frozen lock will understand why)

    All other functions will be 'conveniences'.
    Like having it open windows slightly and starting fans on hot summer days so that the car isn't too hot to sit in.
    Or warning of ice danger in the winter. (just stick a temp sensor under the front bumper, and if it detects air-temperatures of +/- 2 degrees C, assume icy roads)
    Switching off the rear-window de-icing after a set period also makes sense.

    I have a 7" LCD I'm planning to build into it, but as it can be a big distraction, particularly when driving at night, having the computer speak out if there's a problem will be nice. (and very, very cool)

    So...

    I intend to sit back and watch this topic until someone has finished the schematics and code, then steal it and integrate it into my own system...
    (At least I'm honest about it... )

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    Don't visit my new website...
  • Kaos KiddKaos Kidd Posts: 614
    edited 2006-06-26 14:36
    Goog...
    THe sta013 is a mp3 decoder. In full effect it igonres all ID3 tag info while completly decoding MP3 data. It's outputs will directly feed a highspeed dac, and the one indiecated is strong enough to create a 2V PP driver for an amplifer input. The hardest part of this parject is actually getting a fast enough sustained data feed. And, with the MMC/SD interface {Sorries, I forget if it's Javlin or someone else...}, I'm sure the I2C will provide the needed bit rate.

    Brief off topic:
    Kaos: From the infamus Kaos Agents, Agent 99 (what a hottie), and Max: Get Smart!
    Kidd: From the fact that at 42, ALL of the kids on the block still come over to the house every saturday and ask Mrs K if I can come out and play.
    Why the double d in Kidd you ask? In truth, the spelling was derived to be different from the regular spelling of the name. That was, no joke, in the latter part of '75.
    But now, Mrs K and my self have decided that it indeed referes to areas of Mrs K.
    Now, remember this is a "family" place, and thus a strict "G" rating must be maintained, so use your imagination... [noparse]:)[/noparse]

    Back on Topic:
    I have ordered nearly all of the stuff for this project, and the SD card reader. THe original reason for the porpeller was this and a high servo count driver.
    When the MP3 player is done, it will have the following:
    Monitor & Keyboard that folds into the encasement), Audio and Digitle line outs, Audio headphone outs
    Massive Mass storage, with full "managment" access, TCP Ethernet access, Play lists, with all the "fluff and nutter".
    Sync Output (THis is the whole reason for this project turned massive).
    For this project, Synced ouput is the timing of an address / value being outputted to a "bus" of connected devices for on/off and maybe level control, in direct and consistent to the music being played.

    The project's current status is "in progress". The case is designed and built, and for the most part working. The unit's power supply is one from an external Hard drive case, 5.0V@ 10A, 12 & -12V@ 15A. My son and I are both working on this project. I'm hopefull I'll have the majority done for Holloween.

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    Just tossing my two bits worth into the bit bucket


    KK
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  • RinksCustomsRinksCustoms Posts: 531
    edited 2006-06-26 19:57
    Nuttin 4 Nuttin here, but most OBDI & II as well as their predesessors can have the main "sensor" data stream accesed/monitored via the diagnostics port. Data streams in a laptop based application send out a "request" bit, reads and shifts the incoming "x-byte" length into a page in memory that will have the same page updated about every sec. The page itself is usually comprized of roughly 45-50 HEX bytes, each byte representing a different variable to the cars computer and not every byte being a sensor, some are calculated values from multiple sensors. Don't ask because this is an observation of how a GM system works on a OBD1 and pre-OBD1 works. OBDII i think uses a serial interface also, but the 30+ position plug on the diagnostic port suggests a parallel interface for realtime data acquisition of all sensors. Me personally, I think once the data streams are accesible and decipherable for the major manufacturers, we (the enthusiasts of the BS series and the PROpeller) would have a field day with interfacing a talking prop using the text to speech module into our cars. It may just be a pipe dream but it's more feasable than you might think when considering one or more props working tandem, something like the dual cores you see Apple and AMD selling now.

    20MIPS @ 80MHz x 3 cores? What would be the effective comuting power be using 2 cogs rigged for parallel in each PROP in a triangulated mini net?
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