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Thread: Additional USB port for Teensy 3.2

  1. #1
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    Additional USB port for Teensy 3.2

    Hello everybody.
    I would be grateful if you could help me.

    I successfully built a Midi-Controller based on Teensy 3.2. Thank you for the great job dear Teensy team.

    I use my mobile phone as a sound modul, when I plug it in my controller.
    Unfortunally the controller draws current from my phone battery and the phone is losing charge. I would like to prevent this.

    My idea is to add an additional USB port to my controller to plug in my phone while a charger is connected to the built-in USB port of Teensy.

    I have two questions.

    1: Is it possible to solder an USB port in parallel to the built-in Teensy USB port ?

    2: Could I use the additional port for plugging in something else, f.e. my Laptop?

    Many greetings
    Loganjon

  2. #2
    There are USB Y-splitters for charging while also using data. For example, I have one to split my Amazon Fire Stick 4K's lone USB port, which is normally used for power only, so that it can also talk to a flash drive. You also find them on phones that use the lone USB port to, for example, drive earbuds. You need a splitter there to charge at the same time.

    I'm not exactly familiar with your application but I think thats what you need; it'll keep the phone powered while still allowing the data link between phone and Teensy.

  3. #3
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    Quote Originally Posted by dukeblue219 View Post
    There are USB Y-splitters for charging while also using data. For example, I have one to split my Amazon Fire Stick 4K's lone USB port, which is normally used for power only, so that it can also talk to a flash drive. You also find them on phones that use the lone USB port to, for example, drive earbuds. You need a splitter there to charge at the same time.

    I'm not exactly familiar with your application but I think thats what you need; it'll keep the phone powered while still allowing the data link between phone and Teensy.
    Thank you very much for reply:
    I do not like to use the splitters. I prefer an additional fix soldered USB port (maybe even a Type-A)

  4. #4
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    Quote Originally Posted by loganjon View Post
    Hello everybody.
    I would be grateful if you could help me.

    I successfully built a Midi-Controller based on Teensy 3.2. Thank you for the great job dear Teensy team.

    I use my mobile phone as a sound modul, when I plug it in my controller.
    Unfortunally the controller draws current from my phone battery and the phone is losing charge. I would like to prevent this.

    My idea is to add an additional USB port to my controller to plug in my phone while a charger is connected to the built-in USB port of Teensy.
    yes you could solder a USB wires to the bottom pads (GND D+ D+) (NO 5V !) and pluck that into your mobile phone, and power your teensy with a charge only cable,
    OR
    you could cut the VUSB-VIN line on your teensy (No power drawn from Host) and power Vin and GND from 5-6V power supply ( e.g. Battery or charge only cable).
    second solution is easier to solder

  5. #5
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    @WMXZ
    Thank you that help me.

    But just for my knowledge:

    1: In your first suggestion, why should I not solder the 5V?

    2: In your second suggestion, "Cut the VUSB-VIN"
    Do you mean the little gloden bridge between VUSB-VIN? as discribed in this post (https://www.pjrc.com/teensy/external_power.html)?
    Do I have to solder the diode too?

  6. #6
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    I have decided to use the 3-third option (with tow diode) on the Teensy side.
    https://www.pjrc.com/teensy/external_power.html.
    Click image for larger version. 

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    How can I modify to modify this solution to charge my mobile simultaneously, that mean while it is pluged as sound modul
    Last edited by loganjon; 08-26-2019 at 07:30 AM.

  7. #7
    Senior Member+ defragster's Avatar
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    I have OTG adapters for my phone that take power and provide USB device connect - it may charge your phone if it take spower when in Host mode.

  8. #8
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    Quote Originally Posted by defragster View Post
    I have OTG adapters for my phone that take power and provide USB device connect - it may charge your phone if it take spower when in Host mode.
    Thanky you for your advice
    I am more interested in modifiying my circuit than using an extra adapter.

  9. #9
    Member Rena's Avatar
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    Yes, if you cut that bridge, the Teensy won't draw any power from the USB port (you'll have to provide it to VIN some other way). Or if you solder a USB cable directly to it, you'd have to leave off the red wire, otherwise it would be drawing power from USB (no different than plugging a cable in). If you decide to solder the pads, be careful, they're easily damaged.

    If a Teensy alone (and not some additional hardware you've added) is noticeably draining your phone battery though, you might want to modify your code to use low-power and idle modes. It draws very little current if programmed correctly so if it's causing a problem, probably the software is never letting it idle (or something is shorted).

    An easy but less practical solution is to use an OTG cable to plug a USB hub into the phone, then you can plug as much as you want into it!

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