usb to 3.5 mm jack adapter wiring diagram

Discussion in 'The Projects Forum' started by RodneyB, Oct 22, 2013.

  1. RodneyB

    Thread Starter Well-Known Member

    Apr 28, 2012
    I have a waterproof MP3 player and the adapter which is a USB to 3.5mm Stereo jack plug, has been stolen. In the real world I could go out and buy one or get it on eBay BUT in Zimbabwe we are not afforded such luxuries. Therefore I need to try and make one. The adapter used to charge the MP3 player and was used to transfer the music to the MP3 player. I would appreciate it if someone could give me a wiring diagram of how to make this adapter.
  2. diyfreaks

    New Member

    Oct 18, 2013
    unless wiring details are available, cannot make own cable
    if you have few USB cables to spare, then cut one end of cable, take out wires, strip tip of wire, connect USB, then measure voltages in cable, then check by connecting it to some audio input circuit, by this method only you will be able to "trace" back the wiring.

    or may be its better to order or borrow a cable, then with help of multimeter check continuity, draw diagram, keep it handy to make additional cable.s

  3. wayneh


    Sep 9, 2010
    Standard USB wiring puts the power on the outer pins and (digital) data on the inner two pins. Your device very likely retains the power pins on the outside, but perhaps puts analog audio on the inner two pins?

    Once you can identify the power pins, then you can probe the other conductors with your headphones, to identify the signals.

    Oh, power ground and audio ground are likely shared, so that the two inner conductors are the left and right audio.