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Does anyone know how to simultaneously power a Nexus 7 tablet while simultaneously reading serial data from an arduino over USB? I have had quite some trouble with this and have attempted multiple combinations of usb splitters but no luck. I have also tried to use the nexus's inductive charging while using the arduino usb power. While this does work I need to use the Nexus NFC chip at the same time. What I really need is a solution that allows me USB Data, NFC, and power all at the same time.

  • You could make a custom cable with three plugs. Connect all red and black wires, but only the other two between the arduino and the nexus. When you plugin the third plug into an DC-Source, both devices get powered. The serial connection should work. Did this with an openmoko freerunner once. – ansi_lumen Apr 13 '16 at 4:15
  • Do you have any tutorials or articles you could point me to for how to get started with this? – Peace Apr 13 '16 at 4:49
  • I have been at this for 3 days with no luck. Ive cut up and spliced every combination of usb cable i can think of. Does anyone else have any other thoughts? – Peace Apr 15 '16 at 23:34
  • Oh, I remember that I had to solder a resistor somewhere to make the phone charger think, he can deliver more mA. The charger tend to limit the power to 500mA, which may not be enough though. Try to trick the charger into thinking, that he could provide more mA, because the client can "load" faster. Also try a completely different power supply, preferably not a phone charger. – ansi_lumen Apr 16 '16 at 0:30
  • I can speak only to the USB power, and this is a good article (you can ignore the parts about USB-C): androidauthority.com/usb-type-c-and-3-1-explained-656552 To be clear, it's POSSIBLE you wired the cable correctly (did communication work??) but without the resistor then the Nexus will deliberately limit it's power draw to 500ma, or not try to charge at all. a USB OTG cable might also do the trick.. – Scott Prive Nov 13 '17 at 15:28

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