PCB hacking v.power

Discussion in 'OT Technology' started by J, Jun 11, 2009.

  1. J

    J Active Member

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    PCB1 draws power from an AC adapter
    PCB2 draws power from a AAA battery

    Would it be possible to snap off the AAA battery ends and wire both boards together so that PCB2 draws power from the AC adapter via PCB1? How much do you think I'd need to fuck with the resistors and capacitors and what not?
     
  2. OniMinion

    OniMinion ...recalls when this forum was actually about cars OT Supporter

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    AAA = DC
     
  3. J

    J Active Member

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    Is that a "yes" or a "no, definitely not" or a "you need to make this a lot more complicated by converting it"?

    I know next to nothing about this stuff :hs:
     
  4. OniMinion

    OniMinion ...recalls when this forum was actually about cars OT Supporter

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    I guess my post meant "not worth it".
     
  5. Sailor Jerry

    Sailor Jerry OT Supporter

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    Assuming you're talking about a wall wart when you say AC Adapter, the power has already been converted to DC. You just need some sort of regulator to drop it from whatever it is at now to the 1.5V an AAA puts out.

    All in all, probably more trouble than it's worth.
     
  6. mobbarley

    mobbarley Active Member

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    Yes it is very possible, they both have to be very similar voltages and the adapter should have enough current to run both.

    how about the details of each pcb and the power adapter. check the labels for voltage ac/dc (yes some boards take ac in) and power consumption mA/W.
     
  7. J

    J Active Member

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    Ultimately, what I'm trying to do is this:

    I've got a cheap knock off of Apple's Universal iPod Dock (PCB1). It uses iPod's 30 pin connection --> ac adaptor/usb. I need to figure out the easiest or best way to attach a speaker amp (PCB2) to it so that power from PCB1 runs through PCB2.

    The dock already has a headphone amp installed (LM4811). I'm trying to decide if I should rip the chips and everything relevant out and convert it into a high-power system, or just make/buy a small portable speaker amp and wire it to draw power from the dock without using a battery.

    My dillemas:
    - Making an amp (PCB2) wont be a problem -- instructables has some tutorials for decent amps. It's where the heck I'd attach it on the iPod dock to draw power that's got me stumped.
    - Alternatively, I'm afraid I'll fry the dock's entire circuitry if I attempt to frankenstein a new amp out of the already installed headphone amp on the dock. I'm also unsure if any other chip would actually fit on the board.

    I'm a total newb, so I'm learning as I go while trying to figure out what each chip and circuit does on the dock. Although, from what I hear, trying to map out a pcb is already a pain in the ass for even skilled techs.

    Bottom line, the whole thing needs to be powered from one source and be as compact as possible.



    Cliffs: Halp
     
  8. J

    J Active Member

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    I don't have the parts on me right now, but I can hopefully get some pictures up tomorrow of the dock's pcb. Fortunately everything on it is labeled except for one large chip.

    The amp is a lot more flexible. My original question was just wondering if it was possible/feasable.
     
  9. mobbarley

    mobbarley Active Member

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    yeah get some pics. the LM4811 will work great as a preamp section for an amp board if it has volume controls already.

    1: two power adapters will be easier, just use the headphone output as the input to any poweramp.

    2: one power adapter is harder but definitely doable. You'll need to run the dock from the amp's power supply and not the other way around, so if you can post details of what amp you want to use and what the dock requires (look at the transformer it came with) we can go from there.
     
  10. eideteker

    eideteker Who jarked off in my frakkin' coffee? OT Supporter

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    I really don't mean to thread-crap...think of it more as a wake-up-call.

    This won't be a problem, but you don't know the difference between AC and DC? I'm no wizard when it comes to reverse-engineering things or adding functionality in the manner you are attempting, but I'd at least know what all is involved before starting.

    That being said, I hope you get it figured out and get it working, it sounds like a cool project.
     
  11. mobbarley

    mobbarley Active Member

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    yeah i'd get some computer speakers and steal the amp board out of that, it will save you a lot of headache.
     
  12. avctechsupp

    avctechsupp New Member

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    First things first: I often have 'exciting ideas' similar to the one you're describing. However, I often eventually realize that instead of trying to "reinvent the wheel", the smarter thing to do with that creative energy is to build upon the ideas of others.
    Spending countless amounts of time and energy leaning how to engineer a new gizmo for your one specific application....is certainly a noble goal. But, IMHO, the more clever man would devise a way to solve the original problem with much less work!


    NOW, about your application...

    -Do you want the audio from your iPod/iPhone to travel through the dock to a SPEAKER _OR_ SPEAKER AMP? (i.e. do you just want a 'loud' speaker for your iPod, and you don't want to worry about an extra power adapter or batteries for that speaker? _OR_ do you require a speaker amplifier, like the one built into a surround sound system, so that you can connect external speakers to it using speaker wire?)

    Why don't you just do this: Buy a powered speaker (I have the Altec Lansing "orbit MP3". It's truly amazing, given it's size. Runs on 3x AAA (each AAA is 1.5V; total = 4.5VDC) and connect it to the dock's LINE-out. If you can't live with batteries, and assuming your speaker/amp requires only ~5VDC, just buy one a universal AC-to-USB adapter that has 2 USB ports. Use one for the dock, and the other for the speaker/amp. So, in the case of that Altec Lansing speaker I mentioned, you could probably power it via the 2nd USB port. EH?
     
  13. Doc Brown

    Doc Brown Don't make me make you my hobby

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    Yeah, but it outputs DC.


    edit* I see that was already addressed.
     

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