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I am trying to figure out a way to give power to an android tablet and a DSLR camera at the same time (for a photo booth).

I was able to purchase an AC adaptor "battery" plugin for the camera, but the DSLR needs to be plugged in to the tablet via an OTG data cable (USB).

My question is; Can I open the USB cable and cut the two power cables (red and black), then wire them to a mobile device wall wart charger?

Basically, I want to open the USB cord and not cut the data cables so that the camera and tablet are still connected via data, but I want to remove the red and black wires going to the camera (so the camera does not get power). Instead, I want the power wires going from the tablet to go to AC power via a mobile device wall wart charger. will this ruin any data transfer? Does the data need to be transferred with the power for information to be sent?

I think I've over-explained enough, but please ask if I haven't made sense.

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  • \$\begingroup\$ This is probably doable, though you should not cut the ground wire, only splice it, so the link has a ground reference. \$\endgroup\$
    – alex.forencich
    Jan 6, 2016 at 2:48
  • \$\begingroup\$ @alex.forencich Great point! So only cut positive, so it doesn't go to the camera? \$\endgroup\$
    – ntgCleaner
    Jan 6, 2016 at 2:53
  • \$\begingroup\$ Actually, this may not be possible. Specifically which android tablet are you using? Some devices will not charge when acting as a USB host, others can be configured to accept a charge. A special adapter cable will probably be necessary in this case to indicate that a charger is connected, even though the device is acting as a USB host. \$\endgroup\$
    – alex.forencich
    Jan 6, 2016 at 2:58
  • \$\begingroup\$ Try searching for 'USB OTG host power' cables. Make sure your phone will work with one of these, though. \$\endgroup\$
    – alex.forencich
    Jan 6, 2016 at 3:02
  • \$\begingroup\$ Hmm. Is there a way to find out? I will be using a Samsung Galaxy tab 4 (8"). Or should I just test it? I know that when I plug in an OTG cable to my note 4, it asks if I want to use it as media or charge. The tab 4 doesn't ask that... I might just have to sacrifice a cable to test it. As long as you don't think it will damage either device. \$\endgroup\$
    – ntgCleaner
    Jan 6, 2016 at 3:03

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Yes the power and ground lines are needed. The ground line is needed because the OTG feature works by grounding the ID pin the the USB plug. If the ID pin is left floating then the object configures as a device. If the pin is grounded then the object configures as a host. The power line is needed because most if not all devices use the presence of power as a trigger to initiate USB enumeration. If no power is present then the object will not check the data lines to see if something is present.

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