Science Project, MagSafe 1

Discussion in 'MacBook Pro' started by Azathoth123, Jan 15, 2019.

  1. Azathoth123 macrumors 6502

    Joined:
    Sep 13, 2018
    Location:
    Fountain City
    #1
    Hello gents,

    I’m wanting to make a USB-C to Magsafe1 cable and have questions. I have the parts.

    1. Is this possible? Lol.

    2. Any advice, cautions, etc WRT wiring?

    Cheers, Azy
     
  2. leman macrumors G3

    Joined:
    Oct 14, 2008
    #2
    Magsafe uses a dedicated processing unit and a signalling scheme to establish a connection between the charger and the laptop. You'd need to write low-level code and use a custom logic board that will emulate this protocol correctly in order for it to work. This will probably involve reverse-engineering the protocol. The only detailed info (certainly not enough to do what you want) I know of is presented in this blog:

    http://www.righto.com/2013/06/teardown-and-exploration-of-magsafe.html

    P.S. It I understand it correctly, authenticity of the charger is cryptographically protected so you probably will have to hack that protection as well. Have fun :D
     
  3. Azathoth123 thread starter macrumors 6502

    Joined:
    Sep 13, 2018
    Location:
    Fountain City
    #3
    Interesting. The Magsafe 1 has 5 pins, the 2 outer are ground, the next two in are power, and a 5th center pin seems to be connected to a chip inside the magsafe connector. So if I have the correct voltage on the pins, how does it know what it’s connected to? There isn’t any data connection that I can tell - this is old tech.

    But I hear ya, if it was easy someone would have done it already.
     
  4. leman macrumors G3

    Joined:
    Oct 14, 2008
    #4
    It has a data connection (using 1 wire protocol) — read the blog post I linked for details.
     
  5. Azathoth123 thread starter macrumors 6502

    Joined:
    Sep 13, 2018
    Location:
    Fountain City
    #5
    Lol, I’m still trying to grok that, please don’t be annoyed, I appreciate your replies.

    What I don’t clearly understand is that what that 1-wire chip talks to, the Mac, the charger, or both, and how does it do that over what seems to be a simple +/- connection?

    I’m an idiot at these kinds of things but learning is fun, thanks!

    Cheers, Azy
     
  6. jerryk macrumors 601

    Joined:
    Nov 3, 2011
    Location:
    SF Bay Area
    #6
    Aren't there some cable/adapters for USB-C that already have the break-away magnetic connection.

    But, maybe I am not understand what you are trying to do. Where would the USB-C be used? 2016+ MacBook Pro?
     
  7. Azathoth123 thread starter macrumors 6502

    Joined:
    Sep 13, 2018
    Location:
    Fountain City
    #7
    Those adapters are for using a Magsafe charger on a USB-C MacBook, not a USB-C charger on a Magsafe MacBook. Yep, it’s kind of confusing trying to explain.

    Cheers, Azy
     

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